Xamarin

Open Visual Studio and follow these steps:

1. Go to File -> New -> Project.

2. Select Android App (Xamarin), set project name and from templates select Blank App

After creating a blank application, create all resources you will use (icons, images, styles, layouts, etc.). You can copy them from our sample.

Next right click on your project file, then click Properties and go to Android Manifest section.

Setup your Manifest file (app name, app icon, minimum and maximum android versions), make sure to enable Camera permission for this application.

We published our SDK as nuget package on https://www.nuget.org. Please install Cognex.cmbSDK.Xamarin nuget package inside this project.

Note: If you used local XamarinDataManLibrary.dll so far, and now you want to update the SDK, please first remove reference to XamarinDataManLibrary.dll and than install the nuget package.

To use cmbSDK for barcode scanning with a mobile device without an MX mobile terminal, you need to install a license key. If the license key is missing, asterisks will appear instead of scanned results.

Contact your Cognex Sales Representative for information on how to obtain a license key, including 30-day trial licenses.

After obtaining your license key there is two ways to add your license key in application.

The first one is to implement an activation directly from the code when you create your readerDevice:

...
if (param_deviceClass == DataManDeviceClass.PhoneCamera)
{
                //***************************************************************************************
                // Create a camera reader
                //
                // NOTE:  if we're scanning using the built-in camera
                //       of the mobile phone or tablet, then the SDK requires a license key. Refer to
                //       the SDK's documentation on obtaining a license key as well as the methods for
                //       passing the key to the SDK (in this example, we're relying on an entry in
                //       AndroidManifest--there are also getPhoneCameraDevice methods where it can be passed
                //       as a parameter).
                //***************************************************************************************
                readerDevice = ReaderDevice.GetPhoneCameraDevice(this, param_cameraMode, PreviewOption.Defaults, null, "SDK_KEY");
}

and second is to add the following line in the AndroidManifest.xml file of your application under the application tag:

<application>
        .....

     <meta-data android:name="MX_MOBILE_LICENSE" 
          android:value="YOUR_MX_MOBILE_LICENSE"/>
</application>

1. First build your UI according to your needs, but considering the following aspects:

• You have to decide if you you want to show partial or a full screen (that is the default) camera preview. You need a ViewGroup container to use partial preview, for example RelativeLayout.  No additional container is needed for full screen preview. 

Our sample app (that you can find in the cmbSDK bundle) is using full screen preview. To change the sample app to use partial view, add the following RelativeLayout at the end inside main RelativeLayout in activity_scanner.xml file. Use this layout as a ViewGroup parameter in reader device constructor (getPhoneCameraDevice) when reader device is initialized.

<RelativeLayout
        android:id="@+id/rlPreviewContainer"
        android:layout_width="match_parent"
        android:layout_height="200dp"
        android:layout_alignParentTop="true" />

• To display the last scanned image, an ImageView container is needed.
   
• To display the scanned result as a text, a TextView is needed.

2. Set up the following interfaces to monitor the connection state of the reader and receive information about the read code:

public class ScannerActivity : AppCompatActivity, IOnConnectionCompletedListener, IReaderDeviceListener, IOnSymbologyListener, DataManSystem.IOnResponseReceivedListener,
        ActivityCompat.IOnRequestPermissionsResultCallback {

...

#region ReaderDevice listener implementations

        // This is called when a MX-1xxx device has became available (USB cable was plugged, or MX device was turned on),
        // or when a MX-1xxx that was previously available has become unavailable (USB cable was unplugged, turned off due to inactivity or battery drained)
        public void OnAvailabilityChanged(ReaderDevice reader)
        {
            if (reader.GetAvailability() == Availability.Available)
            {
                ConnectToReaderDevice();
            }
            else if (reader.GetAvailability() == Availability.Unavailable)
            {
                AlertDialog.Builder alert = new AlertDialog.Builder(this);
                alert
                    .SetTitle("Device became unavailable")
                    .SetPositiveButton("OK", (sender, e) => { })
                    .Create()
                    .Show();
            }
        }

        // The connect method has completed, here you can see whether there was an error with establishing the connection or not
        public void OnConnectionCompleted(ReaderDevice readerDevice, Throwable error)
        {
            // If we have valid connection error param will be null,
            // otherwise here is error that inform us about issue that we have while connecting to reader device
            if (error != null)
            {

                // ask for Camera Permission if necessary
                if (error is CameraPermissionException)
                    ActivityCompat.RequestPermissions(((ScannerActivity)this), new string[] { Android.Manifest.Permission.Camera }, REQUEST_PERMISSION_CODE);

                UpdateUIByConnectionState();
            }
        }

        // This is called when a connection with the readerDevice has been changed.
        // The readerDevice is usable only in the "ConnectionState.Connected" state
        public void OnConnectionStateChanged(ReaderDevice reader)
        {
            ClearResult();
            if (reader.ConnectionState == ConnectionState.Connected)
            {
                // We just connected, so now configure the device how we want it
                ConfigureReaderDevice();
            }

            isScanning = false;
            UpdateUIByConnectionState();
        }

        // This is called after scanning has completed, either by detecting a barcode, canceling the scan by using the on-screen button or a hardware trigger button, or if the scanning timed-out
        public void OnReadResultReceived(ReaderDevice readerDevice, ReadResults results)
        {
            ClearResult();

            if (results.SubResults != null && results.SubResults.Count > 0)
            {
                foreach (ReadResult subResult in results.SubResults)
                {
                    CreateResultItem(subResult);
                }
            }
            else if (results.Count > 0)
            {
                CreateResultItem(results.GetResultAt(0));
            }

            isScanning = false;
            btnScan.Text = "START SCANNING";
            resultListAdapter.NotifyDataSetChanged();
        }

        #endregion

..

3. Instantiate a ReaderDevice object.

Initialize a Reader Device object for MX readers using the following factory method:

//***************************************************************************************
// Create an MX-1xxx reader  (note that no license key in needed)
//***************************************************************************************
readerDevice = ReaderDevice.GetMXDevice(this);

//Listen when a MX device has became available/unavailable
if (!availabilityListenerStarted)
{
     readerDevice.StartAvailabilityListening();
     availabilityListenerStarted = true;
}

The availability of the MX mobile terminal can change when the device turns on or off, or if the USB cable gets connected or disconnected. You can handle those changes using the following ReaderDeviceListener interface method:

public void OnAvailabilityChanged(ReaderDevice reader)

You are recommended to use an MX mobile terminal to scan barcodes. However, cmbSDK also supports using the built-in camera of a mobile device. This includes the support of optional external aimers or illumination, and the customization of the live-stream preview's appearance.

To scan barcodes using the built-in camera of a mobile device, initialize the ReaderDevice object using the getPhoneCameraDevice static method. The camera reader has several options when initialized. The following parameters are required:

• Context
• CameraMode
• PreviewOption
• ViewGroup
• RegistrationKey
• CustomData

The Context parameter provides a reference to the activity you are currently in.

The CameraMode parameter is of type CameraMode defined in CameraMode.java and it accepts one of the values listed in the following table.

These modes provide the following default settings for the reader:

• The zoom feature is available and a button to control it is visible on the live-stream preview (if displayed).
• The simulated hardware trigger (volume control buttons) is disabled.
• When StartScanning() is called, the decoding process is started.

Based on the selected mode, additional illumination options and behaviors are set, also listed in the table.

The PreviewOption parameter is of type PreviewOption defined in PreviewOption.java, and is used to change the reader’s default values or override defaults derived from the selected CameraMode. You can specify the following options:

The ViewGroup (optional) parameter specifies the container for the live-stream preview. If the parameter is left null, a full screen preview is used.

The RegistrationKey (optional) parameter is used to license your SDK with license key that you have

The CustomData (optional) parameter is used for custom tracking

Example

Create a reader with no aimer, no zoom button, and using a soft trigger:

readerDevice = ReaderDevice.GetPhoneCameraDevice(this, CameraMode.NoAimer, PreviewOption.NoZoomButton | PreviewOption.Paused);

This starts a preview with the scanner paused and a soft trigger button to toggle scanning. After pressing the soft trigger button, the expected preview look is this:

The viewfinder in the image has an active scanning surface as a result of having set active symbologies. For more details, see Enabling Symbologies.

From Android 6.0 and above you need to request permission from the user to access the built-in camera of the mobile device.

If the camera cannot be opened due to permission issues, the onConnectionCompleted(readerDevice, error) callback contains a CameraPermissionException in the error parameter. You can check for this exception type with the instanceof operator and request permission within the Activity.

if (error is CameraPermissionException)
      ActivityCompat.RequestPermissions(((ScannerActivity) this), new string[] { Android.Manifest.Permission.Camera }, REQUEST_PERMISSION_CODE);

You need to implement the ActivityCompat.IOnRequestPermissionResultCallback interface in your Activity to catch the user permission result.
To handle user response in onRequestPermissionsResult(…), you can use the following code to retry connecting to the phone camera:

       public override void OnRequestPermissionsResult(int requestCode, string[] permissions, [GeneratedEnum] Permission[] grantResults)
        {
            // Check result from permission request. If it is allowed by the user, connect to readerDevice
            if (requestCode == REQUEST_PERMISSION_CODE)
            {
                if (grantResults.Length > 0 && grantResults[0] == Permission.Granted)
                {
                    if (readerDevice != null && readerDevice.ConnectionState != ConnectionState.Connected)
                        readerDevice.Connect(this);
                }
                else
                {
                    if (ActivityCompat.ShouldShowRequestPermissionRationale(((ScannerActivity)this), Android.Manifest.Permission.Camera))
                    {
                        AlertDialog.Builder builder = new AlertDialog.Builder(this)
                                .SetMessage("You need to allow access to the Camera")
                                .SetPositiveButton("OK", (sender, e) =>
                                {
                                    ActivityCompat.RequestPermissions(this, new string[] { Android.Manifest.Permission.Camera }, REQUEST_PERMISSION_CODE);
                                })
                                .SetNegativeButton("Cancel", (sender, e) => { });
                        AlertDialog dialog = builder.Create();
                        dialog.Show();
                    }
                }
            }
        }

Before connecting, set the IReaderDeviceListener object to receive events:

readerDevice.SetReaderDeviceListener(this);

Additionally, you can enable sending the last triggered image and SVG from the reader:

readerDevice.EnableImage(true);
readerDevice.EnableImageGraphics(true);

Invoke the connect method after initializing the ReaderDevice and setting a listener method to handle responses from the reader. The connect method takes IOnConnectionCompletedListener as parameter:

 //Make sure the device is turned ON and ready
readerDevice.Connect(ScannerActivity.this);

The following listener methods are called with the new ReaderDevice status information:

public void onConnectionStateChanged(ReaderDevice reader);
public void onConnectionCompleted(ReaderDevice reader, Throwable err)

The onConnectionCompleted method passed as a parameter of connect is also invoked as the connection process completes. If there was a connection error, this method provides a Throwable object.

After connecting to the scanning device, you may need to change some of its settings. CmbSDK provides a set of high-level and device-independent APIs for setting and retrieving the current configuration of the device.

You can start scanning barcodes with a properly configured reader by calling the StartScanning method from your ReaderDevice class:

readerDevice.StartScanning();

• If using an MX mobile terminal, you can press a trigger button on the device to turn the scanner on and read a barcode.
• If using the camera reader, cmbSDK starts the camera, displays the configured live-stream preview, and begins analyzing the frames from the video stream, looking for a configured barcode symbology.

You can stop scanning with the following:

readerDevice.StopScanning();

Scanning stops under one of the following conditions:

• The reader found and decoded a barcode.
• You released the trigger or pressed the stop button on the live-stream preview screen.
• The camera reader timed out without finding a barcode.
• The application calls the StopScanning() method.

When a barcode is decoded successfully, you receive a ReadResults iterable result collection object in the ReaderDevice listener method. The onReadResultReceived listener method is invoked either because the reader decoded a barcode or the scanning process was complete.

Example

        // This is called after scanning has completed, either by detecting a barcode, canceling the scan by using the on-screen button or a hardware trigger button, or if the scanning timed-out
        public void OnReadResultReceived(ReaderDevice readerDevice, ReadResults results)
        {
            ClearResult();

            if (results.SubResults != null && results.SubResults.Count > 0)
            {
                foreach (ReadResult subResult in results.SubResults)
                {
                    CreateResultItem(subResult);
                }
            }
            else if (results.Count > 0)
            {
                CreateResultItem(results.GetResultAt(0));
            }

            isScanning = false;
            btnScan.Text = "START SCANNING";
            resultListAdapter.NotifyDataSetChanged();
        }

CmbSDK does not enable any symbologies by default for barcode reading with the built-in camera of the mobile device. You must enable all barcode symbologies your application needs to scan to achieve optimal scanning performance.

Individual symbologies can be enabled using the following method of the ReaderDevice class:

public void SetSymbologyEnabled(final Symbology symbology, final boolean enable, final IOnSymbologyListener listener)
readerDevice.SetSymbologyEnabled(Symbology.Datamatrix, true, null);
readerDevice.SetSymbologyEnabled(Symbology.UpcEan, true, null);

All symbologies used for the symbology parameter in this method can be found in ReaderDevice.java.

Examples

 /* Enable QR scanning */
readerDevice.SetSymbologyEnabled(Symbology.Qr, true, null);

You can also use the same method to disable symbologies:

/ * Disable Code 25 scanning */ readerDevice.SetSymbologyEnabled(Symbology.C25, false, null);

You can implement the method for IOnSymbologiesListener to check the result of the symbology change:

public void onSymbologyEnabled(ReaderDevice reader, Symbology symbology, Java.Lang.Boolean enabled, Throwable error) {
if (error != null) {
/* Unsuccessful
probably the symbology is unsupported by the current device, or there is a problem with the connection between the readerDevice and MX device */
} else {
// Success }
}

If your reader device is equipped with illumination lights, you can control them: when scanning starts, you can turn them on or off. Use the following method of your Reader Device object:

readerDevice.SetLightsOn(true, null);

You can implement the interface method for IOnLightsListener, which is the second parameter of the method.

public class ScannerActivity : AppCompatActivity, .... IOnLightsListener .... { ....

public void onLightsOnCompleted(ReaderDevice reader, Java.Lang.Boolean on, Throwable error) {
if (error != null) { // Unsuccessful
} else {
// Success
}}

If the built-in camera of a mobile device is used as the reader device, you can configure zoom levels and how they are used. There are three zoom levels:

• normal: not zoomed (100%)
• level 1 zoom (150% on Android by default)
• level 2 zoom (300% on Android by default)

The SET CAMERA.ZOOM-PERCENT [100-MAX] [100-MAX] command is for configuring how far the two levels zoom in percentage. 100 is not zoomed and MAX (goes up to 1000) zooms as far as the device is capable of. The first argument is used for setting level 1 zoom, and the second for level 2 zoom.

You can check the current zoom setting with the GET CAMERA.ZOOM-PERCENT command, which returns two values: level 1 and level 2 zoom.

Example

readerDevice.DataManSystem.SendCommand("SET CAMERA.ZOOM-PERCENT 250 500");

GET/SET CAMERA.ZOOM 0-2 is another command that sets the zoom level or returns the actual setting. Possible values for the SET command are:

• 0 - normal (not zoomed)
• 1 - level 1 zoom
• 2 - level 2 zoom

You can call this command before or even during scanning, and the zoom goes up to the configured level. If scanning is finished, the value is reset to normal behavior (0).

Example

readerDevice.DataManSystem.SendCommand("SET CAMERA.ZOOM 2");

When using the mobile device's camera, cmbSDK allows you to see the camera preview inside a preview container or in full screen. This preview also contains a customizable overlay. The cmbSDK camera overlay features buttons for zooming, flashing and closing the scanner, and a progress bar indicating the scan timeout.

To use the legacy camera overlay originally used in cmbSDK v2.0.x and ManateeWorks SDK, use this property from MWOverlay before initializing the readerDevice:

MWOverlay.OverlayMode = MWOverlay.OverlayModeEnum.OmLegacy;

When using the cmbSDK overlay:

1. Copy the layout files from the Resources/layout directory into your project and modify them. Use cmb_scanner_partial_view.xml if scanning is started inside a container (partial view), and use cmb_scanner_view.xml if scanning is started in full screen.
2. Modify the layout according to your needs. For example, you can change the sizes, positions or color of the views, remove views and add your own views, like an overlay image.

Both the cmbSDK and the legacy overlay allow you to change the images used on the zoom and flash buttons if your images have the same name as the names cmbSDK uses. You can find the images and names used in cmbSDK in the Resources/drawable-mdpi and drawable-hdpi directories. While the other resolutions are optional, these two directories must contain your images with the correct names so that cmbSDK displays the proper images.

Both the cmbSDK and the legacy overlay allow you to change the color and width of the rectangle that is displayed when a barcode is detected.

Example:

MWOverlay.LocationLineColor = Color.Yellow;
MWOverlay.LocationLineWidth = 6;

Cognex scanning devices implement DataMan Control Commands (DMCC) for configuring and controlling the device. Every feature of the device can be controlled using this text-based language. The API provides a method for sending DMC commands to the device. Commands exist both for setting and querying configuration properties. DMC commands are same for all platforms and frameworks.

The Appendix includes the complete DMCC reference for the camera reader.

The following examples show different DMCC sent to the device for more advanced configuration.

Examples

//Change the scan direction to omnidirectional 
readerDevice.DataManSystem.SendCommand("SET DECODER.1D-SYMBOLORIENTATION 0", ScannerActivity.this);
//Change live-stream preview's scanning timeout to 10 seconds 
readerDevice.DataManSystem.SendCommand("SET DECODER.MAX-SCAN-TIMEOUT 10", ScannerActivity.this);

You can also invoke DMCC query commands and receive their response in the IOnResponseReceivedListener.onResponseReceived() method.

//Get the type of device connected readerDevice.DataManSystem.SendCommand("GET DEVICE.NAME", this);

public void onResponseReceived(DataManSystem dataManSystem, DmccResponse dmccResponse) {
if (dmccResponse.Error != null) {
// Unsuccessful
Log.e("DMCC_ERR", “GET DEVICE.NAME failed”, dmccResponse.Error.Message);
} else {
// Success - Use the following result fields:
//int mResponseId = dmccResponse.ResponseId;
//String mPayLoad = dmccResponse.PayLoad;
//byte[] mBinaryData = dmccResponse.GetBinaryData(); 
} }

CmbSDK includes a method for resetting the device to its default settings. In case of an MX mobile terminal, the default setting are the saved configurations. In case of a built-in camera, the default settings are the defaults identified in the Appendix, where no symbologies are enabled.

To reset the device, add:

readerDevice.ResetConfig(null);

When using an MX mobile terminal, there are three states that we can distinguish:

• Factory defaults
• Saved configuration: when there were different configurations set on the device and CONFIG.SAVE DMCC was called.
• Session configuration: when you make changes on the saved configuration, the changes are valid until the MX Mobile Terminal is rebooted. If it is rebooted, it has the saved configuration state.

You can monitor the completion of this async method using the IOnResetConfigListener interface, which is an optional parameter.

public class ScannerActivity : AppCompatActivity, .... IOnResetConfigListener .... { ....

public void onResetConfigCompleted(ReaderDevice reader, Throwable error) {
if (error != null) { // Unsuccessful
} else {
// Success
}

When a barcode is successfully read, the onReadResultReceived method creates and returns a ReadResult object. In case of having multiple barcodes successfully read on a single image or frame, multiple ReadResult objects are returned in the ReadResult object.

The ReadResult class has properties describing the result of a barcode read:

• IsGoodRead (bool): tells whether the read was successful or not
• ReadString (string): the decoded barcode as a string
• Image (Bitmap): the image/frame that the decoder processed
• ImageGraphics (string): the boundary path of the barcode as SVG data
• Xml (string): the raw XML that the decoder returned
• Symbology (Symbology): the symbology type of the barcode. This enum is defined in ReaderDevice.java.

When a scanning ends with no successful read, a ReadResult is returned with the IsGoodRead property set to false.

To enable the Image and ImageGraphics properties being filled in the ReadResult object, set the corresponding EnableImage() and/or EnableImageGraphics() properties of the ReaderDevice object.

To access the raw bytes from the scanned barcode, you can use the XML property. The bytes are stored as a Base64 string under the "full_string" tag.

The image and SVG results are disabled by default, which means that when scanning, the ReadResults do not contain any data in the corresponding properties.

To enable image results, invoke the EnableImage() method from the ReaderDevice object:

readerDevice.EnableImage(true);

To enable SVG results, invoke the EnableImageGraphics() method on ReaderDevice object:

readerDevice.EnableImageGraphics(true); 

If a device disconnects due to low battery condition or manual cable disconnection, it can be detected by the onConnectionStateChanged() method of the IReaderDeviceListener interface.

Open Visual Studio and follow this steps:

1. Go to File -> New -> Project.

2. Select iOS App (Xamarin) , set project name and from templates select Blank App

After creating a blank application, create all resources you will use (images, storyboards, controllers, etc.). You can copy them from our sample.

Next open your Info.plist file and set some project properties for your needs (app name, deployment target, main interface, etc..).

Important thing here is to add Camera permission for this app. In Visual Studio there is no options to add this permission from here. You need to open your Info.plist file in some text editor and add these lines:

<key>NSCameraUsageDescription</key>
<string>Camera used for scanning</string>

If you use MX Device as reader device add this protocols in Info.plist:

<key>UISupportedExternalAccessoryProtocols</key>
<array>
  <string>com.cognex.dmcc</string>
  <string>com.demo.data</string>
</array>

and please check this section before uploading your app on the App Store: Getting your MX Mobile Terminal Enabled App into the App Store

We published our SDK as nuget package on https://www.nuget.org. Please install Cognex.cmbSDK.Xamarin nuget package inside this project.

Note: If you used local XamarinDataManLibrary.dll so far, and now you want to update the SDK, please first remove reference to XamarinDataManLibrary.dll and than install the nuget package.

If you plan to use your application on devices with iOS lower than 12.2 extra steps are required:

• Add Swift dylib dependencies for runtime support. Starting from iOS 12.2 and Swift 5.1, the language became ABI (application binary interface) stable and compatible. That's why any application targeting a lower iOS version needs to include Swift dylibs dependencies used by the framework. Use the SwiftRuntimeSupport NuGet package to automatically include required dylib dependencies into the resulting application package.
• Add SwiftSupport folder with signed dylibs, which is validated by the AppStore during the uploading process. The package should be signed and distributed to the AppStore connect using Xcode tools, otherwise, it will be automatically rejected.

Note: This package works only on real devices. You won't be able to test your application on simulators with an iOS version lower than 12.2.

To use cmbSDK for barcode scanning with a mobile device without an MX mobile terminal, you need to install a license key. If the license key is missing, asterisks will appear instead of scanned results.

Contact your Cognex Sales Representative for information on how to obtain a license key, including 30-day trial licenses.

After obtaining your license key there is two ways to add your license key in application.

The first one is to implement an activation directly from the code when you create your readerDevice:

//***************************************************************************************
// Create a camera reader (for either the built-in camera)
//
// NOTE: If we're scanning using the built-in camera of the mobile phone or tablet,
//       then the SDK requires a license key.
//       Refer to the SDK's documentation on obtaining a license key as well as the methods for
//       passing the key to the SDK (in this example, we're relying on an entry in
//       plist.info--there are also readerOfDeviceCamera methods where it can be passed
//       as a parameter).
//***************************************************************************************
case DataManDeviceClass.PhoneCamera:
     readerDevice = CMBReaderDevice.ReaderOfDeviceCameraWithCameraMode(cameraMode, CDMPreviewOption.Defaults, null, "SDK_KEY");
     break;

and second is to add it as a key with a value in the project specific Info.plist file:

<key>MX_MOBILE_LICENSE</key>
<string>Your license key</string>

1. First build your UI According to your needs:

   • If you want to show partial camera preview, you need a View container, for example a UIView 
   • If you want to use full screen preview (default) you do not need any additional containers.
     • For example if we want to use partial view in our sample application: add a UIView in the Main storyboard with the desired dimensions and constraints, and use it in reader device constructor (previewView parameter) when reader device is initialized.
   • If you want to display the last scanned image, add a UIImageView for container instead of UIView for showing the last frame of a preview or scanning session.

   • If you want to display the scanned result as a text, add UILabel.
      

2. Set up the following interfaces to monitor the connection state of the reader and receive information about the read code:
    

   //----------------------------------------------------------------------------
           // When an applicaiton is suspended, the connection to the scanning device is
           // automatically closed by iOS; thus when we are resumed (become active) we
           // have to restore the connection (assuming we had one). This is the observer
           // we will use to do this.
           //----------------------------------------------------------------------------
           void AppBecameActive(NSNotification obj)
           {
               if (readerDevice != null && readerDevice.Availability == CMBReaderAvailibility.Available && readerDevice.ConnectionState != CMBConnectionState.Connecting && readerDevice.ConnectionState != CMBConnectionState.Connected)
               {
                   ConnectToReaderDevice();
               }
           }
   
           public override void ViewDidLoad()
           {
               base.ViewDidLoad();
   
               // Add our observer for when the app becomes active (to reconnect if necessary)
               NSNotificationCenter.DefaultCenter.AddObserver(UIApplication.DidBecomeActiveNotification, AppBecameActive);
           }
   
   
   // This is called when a MX-1xxx device has became available (USB cable was plugged, or MX device was turned on),
           // or when a MX-1xxx that was previously available has become unavailable (USB cable was unplugged, turned off due to inactivity or battery drained)
           [Export("availabilityDidChangeOfReader:")]
           public void AvailabilityDidChangeOfReader(CMBReaderDevice reader)
           {
               ClearResult();
   
               if (reader.Availability != CMBReaderAvailibility.Available)
               {
                   ShowAlert(null, "Device became unavailable");
               }
               else
               {
                   ConnectToReaderDevice();
               }
           }
   
           // This is called when a connection with the self.readerDevice has been changed.
           // The self.readerDevice is usable only in the "CMBConnectionStateConnected" state
           [Export("connectionStateDidChangeOfReader:")]
           public void ConnectionStateDidChangeOfReader(CMBReaderDevice reader)
           {
               isScanning = false;
               ClearResult();
   
               if (readerDevice.ConnectionState == CMBConnectionState.Connected)
               {
                   // We just connected, so now configure the device how we want it
                   ConfigureReaderDevice();
   
                   if (connectingAlert != null)
                   {
                       connectingAlert.DismissViewController(true, () =>
                       {
                           connectingAlert = null;
                       });
                   }
               }
               else if (readerDevice.ConnectionState == CMBConnectionState.Disconnected && connectingAlert != null)
               {
                   connectingAlert.DismissViewController(true, () =>
                   {
                       connectingAlert = null;
                   });
               }
   
               UpdateUIByConnectionState();
           }
   
           // This is called after scanning has completed, either by detecting a barcode, canceling the scan by using the on-screen button or a hardware trigger button, or if the scanning timed-out
           [Export("didReceiveReadResultFromReader:results:")]
           public void DidReceiveReadResultFromReader(CMBReaderDevice reader, CMBReadResults readResults)
           {
               isScanning = false;
               btnScan.Selected = false;
   
               scanResults.RemoveAllObjects();
   
               if (readResults.SubReadResults != null && readResults.SubReadResults.Length > 0)
               {
                   scanResults.AddObjects(readResults.SubReadResults);
               }
               else if (readResults.ReadResults.Length > 0)
               {
                   scanResults.Add(readResults.ReadResults[0]);
               }
   
               tableViewSource.SetItems(scanResults);
               tvResults.ReloadData();
           }

    

3. Instantiate a CMBReaderDevice object.

    

Initializing the CMBReaderDevice for use with an MX mobile terminal like the MX-1000, MX-1100, or MX-1502 is easy: simply create the reader device using the MX device method (it requires no parameters), and set the appropriate delegate (normally self):

readerDevice = CMBReaderDevice.ReaderOfMXDevice();
readerDevice.WeakDelegate = this;

The availability of the MX mobile terminal can change when the device turns ON or OFF, or if the lightning cable gets connected or disconnected. You can handle those changes using the following CMBReaderDeviceDelegate method.

public void AvailabilityDidChangeOfReader(CMBReaderDevice reader)

Barcode scanning with the built-in camera of the mobile device can be more complex than with an MX mobile terminal. Therefore the cmbSDK supports several configurations to provide the maximum flexibility, including support of optional external aimers and illumination, as well as the ability to customize the appearance of the live-stream preview. 

To scan barcodes using the built-in camera of the mobile device, initialize the CMBReaderDevice object using the ReaderOfDeviceCameraWithCameraMode static method. The camera reader has several options when initialized. The following parameters are required:

* CDMCameraMode
* CDMPreviewOption
* UIView

The CameraMode parameter is of the type CDMCameraMode, and it accepts one of the following values:

• NoAimer: If no aiming accessory is available, this mode initializes the live-stream preview on the screen to help positioning the barcode in the field of view for detection and decoding.
• PassiveAimer: Initializes passive aimer use, which is an external accessory that uses the device's built-in LED flash for illumination to project an aiming pattern. In this mode no live-stream preview is presented on the screen.
• FrontCamera: Initializes use of the front facing camera. In this mode, illumination is not available.

The above modes provide the following default settings for the mobile device as a code reader:

• The simulated hardware trigger is disabled.
• When StartScanning() is called, the decoding process is started. (Seek CDMPreviewOption.Paused for more details).

Based on the selected mode, the following additional options and behaviors are set:

• NoAimer
  • The live-stream preview is displayed when the StartScanning() method is called.
  • Illumination and control button are available and visible on the live-stream preview.
  • Aimer control commands are ignored.

• PassiveAimer
  • The live-stream preview will not be displayed when the StartScanning() method is called by default.
  • Illumination is not available
  • Illumination control commands are ignored.

• FrontCamera
  • The live-stream preview is displayed when the StartScanning() method is called.
  • The front camera is used.
  • Illumination and the control button are not available.
  • Illumination or aimer control commands are ignored.

The previewOptions parameter (of type CDMPreviewOption) is used to change the reader’s default values or override defaults derived from the selected CameraMode. Multiple options can be specified by OR-ing them when passing the parameter. The available options are the following:

• Defaults: Accept all defaults set by the CameraMode.
• NoZoomBtn: Hide the zoom button on the live-stream preview.
• NoIllumBtn: Hide the illumination button on the live-stream preview.
• HwTrigger: Enable simulated hardware trigger (volume controls) for starting scanning. When pressed, scanning starts.
• Paused: Display the live-preview when the StartScanning() method is called without starting the decoding (i.e. looking for barcodes). Pressing the on-screen scanning button starts the decoding.
• AlwaysShow: Force display of live-preview when passive aiming mode has been selected (e.g. CameraMode == PassiveAimer )
• HighResolution: Use the device camera in higher resolution to help with scanning small barcodes, but slow decode time. The option sets resolution to 1920x1080 on devices that support it, and the default one on devices that do not.The default resolution is 1280x720.
• HighFrameRate: Sets the camera to 60 FPS instead of the default 30 FPS to provide a smoother camera preview.

Examples:

Create a reader with no aimer and a full screen live-stream preview:

readerDevice = CMBReaderDevice.ReaderOfDeviceCameraWithCameraMode(CDMCameraMode.NoAimer, CDMPreviewOption.Defaults, null);
readerDevice.WeakDelegate = this;

Create a reader with no aimer, no zoom button, and using a simulated trigger:

readerDevice = CMBReaderDevice.ReaderOfDeviceCameraWithCameraMode(CDMCameraMode.NoAimer, CDMPreviewOption.NoZoomBtn | CDMPreviewOption.HwTrigger, null);
readerDevice.WeakDelegate = this;

Initialize the CMBReaderDevice and set a delegate to handle responses from the reader.

Then connect using ConnectWithCompletion:

// Make sure the device is turned ON and ready
if (readerDevice.Availability == CMBReaderAvailibility.Available && readerDevice.ConnectionState == CMBConnectionState.Disconnected)
{
    readerDevice.ConnectWithCompletion((error) =>
    {
        if (error != null)
        {
            ShowAlert("Failed to connect", null);
        }
    });
}

When connected ConnectionStateDidChangeOfReader in the delegate is called, where you can check the connection status in your Reader Device's ConnectionState parameter. It should be CMBConnectionState.Connected, which means that you have successfully made the connection to the CMBReaderDevice, and can begin using the Cognex Mobile Barcode SDK.

Individual symbologies can be enabled using the following method of the CMBReaderDevice object:

readerDevice.SetSymbology(CMBSymbology.DataMatrix, true, null);

All symbologies used for the symbology parameter in this method can be found in CMBSymbology enum.

The same method can also be used to turn symbologies off:

readerDevice.SetSymbology(CMBSymbology.DataMatrix, false, null);

If your reader device is equipped with illumination (e.g. LEDs), you can control whether they are ON or OFF when scanning starts using the following method of your CMBReaderDevice object:

readerDevice.SetLightsON(true, (error) =>
{
    if (error != null)
    {
        System.Diagnostics.Debug.WriteLine("// Failed to enable illumination, Possible causes are: reader disconnected, out of battery or cable unplugged, or device doesn't come with illumination lights");
    }
});

Keep in mind that not all devices and device modes supported by the cmbSDK allow illumination control. For example, if using the built-in camera in passive aimer mode, illumination is not available since the LED is being used for aiming.

If built-in camera is used as reader device you have the possibility to configure zoom levels and define the way these zoom levels are used.

There are 3 zoom levels for the phone camera, which are:

• normal: not zoomed (100%)
• level 1 zoom (default 200%)
• level 2 zoom (default 400%)

You can define these zoom levels with "SET CAMERA.ZOOM-PERCENT [100-MAX] [100-MAX]" command. It configures how far the two levels will zoom in percentage. 100 is without zoom, and MAX (goes up to 1000) will zoom as far as the device is capable of. First argument is used for setting level 1 zoom, and the second for level 2 zoom.

When you want to check current setting, you can do this with the "GET CAMERA.ZOOM-PERCENT" that returns two values: level 1 and level 2 zoom.

Example

readerDevice.DataManSystem.SendCommand("SET CAMERA.ZOOM-PERCENT 250 500");

here is another command that sets which zoom level you want to use or returns the actual setting: "GET/SET CAMERA.ZOOM 0-2".

Possible values for the SET command are:

• 0 - normal (un-zoomed)
• 1 - zoom at level 1
• 2 - zoom at level 2

You can call this command before scanning or even during scanning, the zoom goes up to the level that was configured.

When the scanning is finished, the values are reset to normal(0).

Example

readerDevice.DataManSystem.SendCommand("SET CAMERA.ZOOM 2");

When using the built-in camrea of the mobile device, the cmbSDK allows you to see the Camera Preview inside a preview container or in full screen. This preview also contains an overlay, which can be customized. The cmbSDK camera overlay is built from buttons for zoom, flash, closing the scanner (in full screen), a progress bar indicating the scan timeout, and lines on the corners of the camera preview. There are two available overlays: legacy and CMB overlay.

To use the legacy camera overlay, which was used in the cmbSDK v2.0.x and the ManateeWorks SDK, use this property from MWOverlay before initializing the CMBReaderDevice:

MWOverlay.SetOverlayMode((int) OverlayMode.Legacy);

If using the CMB overlay, you can find the layout files in the Resources/layout directory:

CMBScannerPartialView.xib used when the scanner is started inside a container (partial view)

CMBScannerView.xib when the scanner is started in full screen

Copy the layout file that you need, or both layouts, then modify them as you like. Change the size, position or color of the views, remove views, and add your own views, like an overlay image. The views that are used by the cmbSDK (zoom, flash, close buttons, the view used for drawing lines on the corners, and the progress bar) are accessed by the sdk using the Tag attribute, make sure the Tag attribute remains unchanged, so that the cmbSDK is able to recognize the views and continue to function correctly.

Both the CMB and the legacy overlay allow you to change the images used on the zoom and flash buttons. To do that, first copy the assets folder MWBScannerImages.xcassets from the Resources dir into your project. In VisualStudio you can look at the images contained in this assets folder, and replace them with your own while keeping the image names unchanged.

Both the CMB and the LEGACY overlay allow you to change the color and width of the rectangle that is displayed when a barcode is detected. Here's an example on how to do that:

MWOverlay.SetLocationLineUIColor(UIColor.Yellow);
MWOverlay.SetLocationLineWidth(5);

Every Cognex scanning device implements DataMan Control Commands (DMCC), a method for configuring and controlling the device. Virtually every feature of the device can be controlled using this text based language. The API provides a method for sending DMCC commands to the device. Commands exist both for setting and querying configuration properties.

Appendix A includes the complete DMCC reference for use with the camera reader. DMCC commands for other supported devices (e.g. the MX-1000) are included with the documentation of that particular device.
Appendix B provides the default values for the camera reader’s configuration settings as related to the corresponding DMCC setting.

DMC commands are same for all platforms and frameworks.

The following examples show different DMCC commands being sent to the device for more advanced configuration.

Example:

Change the scan direction to omnidirectional:

readerDevice.DataManSystem.SendCommand("SET DECODER.1D-SYMBOLORIENTATION 0", (response) =>
{
    if (response.Status == CDMResponseStatus.DMCC_STATUS_NO_ERROR)
    {
        // Command was executed successfully
    }
    else
    {
        // Command failed, handle errors here
    }
});

Change the scanning timeout of the live-stream preview to 10 seconds: 

readerDevice.DataManSystem.SendCommand("SET DECODER.MAX-SCAN-TIMEOUT 10", (response) =>
{
    if (response.Status == CDMResponseStatus.DMCC_STATUS_NO_ERROR)
    {
        // Command was executed successfully
    }
    else
    {
        // Command failed, handle errors here
    }
});

Get the type of the connected device:

readerDevice.DataManSystem.SendCommand("GET DEVICE.TYPE", (response) =>
{
    if (response.Status == CDMResponseStatus.DMCC_STATUS_NO_ERROR)
    {
        // Command was executed successfully
    }
    else
    {
        // Command failed, handle errors here
    }
});

The cmbSDK includes a method for resetting the device to its default settings. In the case of an MX mobile terminal, this is the configuration saved by default, while in the case of the built-in camera, these are the defaults identified in Appendix B, where no symbologies will be enabled. This method is the following:

readerDevice.ResetConfigWithCompletion((error) =>
{
    if (error != null)
    {
        // Failed to reset configuration, Possible causes are: reader disconnected, out of battery or cable unplugged
    }
});

With a properly configured reader, you are ready to scan barcodes. This is simply accomplished by calling the StartScanning() method from your CMBReaderDevice object. What happens next is based on the type of CMBReaderDevice and how it has been configured. Generally:

• If using an MX terminal, press a trigger button on the device to turn the scanner on and read a barcode.
• If using the camera reader, the cmbSDK starts the camera, displays the configured live-stream preview, and begins analyzing the frames from the video stream, looking for a configured barcode symbology.

Scanning stops under one of the following conditions:

• The reader found and decoded a barcode.
• The user released the trigger or pressed the stop button on the live-stream preview screen.
• The camera reader timed out without finding a barcode.
• The application program calls the StopScanning() method.

When a barcode is decoded successfully, you will receive a CMBReadResults array in your CMBReaderDevice's delegate using the following ICMBReaderDeviceDelegate method:

public void DidReceiveReadResultFromReader(CMBReaderDevice reader, CMBReadResults readResults)

To simply display a ReadResult after scanning a barcode:

public void DidReceiveReadResultFromReader(CMBReaderDevice reader, CMBReadResults readResults)
{
    if (readResults.ReadResults.Length > 0)
    {
        CMBReadResult readResult = (CMBReadResult)readResults.ReadResults[0];
        
        if(readResult.Image != null)
        {
            ivPreview.Image = readResult.Image;
        }

        if (readResult.ReadString != null)
        {
            lblCode.Text = readResult.ReadString;
        }
    }
}

In the example above, ivPreview is an UIImageView used to display an image of the barcode that was scanned, and lblCode is a UILabel used to show the result from the barcode. You can also use the bool from readResult.GoodRead to check whether the scan was successful or not. 

When a barcode is successfully read, a CMBReadResult object is created and returned by the DidReceiveReadResultFromReader method. In case of having multiple barcodes successfully read on a single image/frame, multiple CMBReadResult objects are returned. This is why the CMBReadResults class has an array of CMBReadResult objects containing all results.

The CMBReadResult class has properties describing the result of a barcode read:

• GoodRead (bool): tells whether the read was successful or not
• ReadString (string): the decoded barcode as a string
• Image (UIImage): the image/frame that the decoder has processed
• ImageGraphics (NSData): the boundary path of the barcode as SVG data
• XML (NSData): the raw XML that the decoder returned
• Symbology (CMBSymbology): the symbology type of the barcode.

When a scanning ends with no successful read, a CMBReadResult is returned with the GoodRead property set to false. This usually happens when scanning is canceled or timed out.

To enable the image and ImageGraphics properties being filled in the CMBReadResult object, you have to set the corresponding ImageResultEnabled and/or SVGResultEnabled properties of the CMBReaderDevice object.

To see an example on how the image and SVG graphics are used and displayed in parallel, refer to the sample applications provided in the SDK package.

To access the raw bytes from the scanned barcode, you can use the XML property. The bytes are stored as a Base64 string under the "full_string" tag.

By default, the image and SVG results are disabled, which means that when scanning, the CMBReadResults will not contain any data in the corresponding properties.

To enable image results, set the ImageResultEnabled property from the CMBReaderDevice class by using the following method:

readerDevice.ImageResultEnabled = false;

To enable SVG results, set the imageResultEnabled property from the CMBReaderDevice class by using the following method: 

readerDevice.SVGResultEnabled = false;

There may be cases when a device disconnects due to low battery condition or manual cable disconnection. These cases can be detected by the ConnectionStateDidChangeOfReader callback of the ICMBReaderDeviceDelegate.

After returning to your application from inactive state, the reader device remains initialized but not connected. There is no need for reinitializing the SDK but you need to re-connect.

Some iOS versions will send an "Availability" notification when resuming the application that the external accessory is available. You can use this in the ICMBReaderDeviceDelegate method: void AvailabilityDidChangeOfReader(CMBReaderDevice reader) so when the reader becomes available, you can connect.

For example:

public void AvailabilityDidChangeOfReader(CMBReaderDevice reader)
{
    if (readerDevice.Availability == CMBReaderAvailibility.Available)
    {
        readerDevice.ConnectWithCompletion((error) =>
        {
            if (error != null)
            {
                // handle connection error
            }

        });
    }
}

Some iOS versions do not report availability change on resume, so you need to handle this manually. Add an observer for UIApplicationDidBecomeActiveNotification and connect.

Example:

public override void ViewDidLoad()
{
    base.ViewDidLoad();

    NSNotificationCenter.DefaultCenter.AddObserver(UIApplication.DidBecomeActiveNotification, AppBecameActive);
}

void AppBecameActive(NSNotification obj)
{
    if (readerDevice != null && readerDevice.Availability == CMBReaderAvailibility.Available && readerDevice.ConnectionState != CMBConnectionState.Connecting && readerDevice.ConnectionState != CMBConnectionState.Connected)
    {
        readerDevice.ConnectWithCompletion((error) =>
        {
            if (error != null)
            {
                // handle connection error
            }
        });
    }
}

Open Visual Studio and follow these steps:

1. Go to File -> New -> Project.

2. Create Mobile App(Xamarin.Forms) , set project name, from templates select Blank and choose Android and iOS platform.

Next right click on your Android platform specific project file, then click Properties and go to Android Manifest section.

Setup your Manifest file (app name, app icon, minimum and maximum android versions), make sure to enable Camera permission.

We should do same for iOS platform specific project. Open your Info.plist file and set some project properties for your needs (app name, deployment target, etc..)

and make sure to add Camera permission. In Visual Studio there is no options to add this permission from here. You need to open your Info.plist file in some text editor and add these lines:

<key>NSCameraUsageDescription</key>
<string>Camera used for scanning</string>

If you use MX Device as reader device add this protocols in Info.plist:

<key>UISupportedExternalAccessoryProtocols</key>
<array>
   <string>com.cognex.dmcc</string>
   <string>com.demo.data</string>
</array>

and please check this section before uploading your app on the App Store: Getting your MX Mobile Terminal Enabled App into the App Store

We published our SDK as nuget package on https://www.nuget.org. Please install Cognex.cmbSDK.XamarinForms nuget package inside this solution. Select all three projects when you install the package.

Note: If you used local XamarinDataManLibrary.dll so far, and now you want to update the SDK, please first remove reference to XamarinDataManLibrary.dll in platform specific projects and than install the nuget package. Also if you don't have any custom code in ScannerConstrol.cs classes you can remove them from all three projects, because this view renderer is now included in the nuget package as well.

If you plan to use your application on devices with iOS lower than 12.2 extra steps are required:

• Add Swift dylib dependencies for runtime support. Starting from iOS 12.2 and Swift 5.1, the language became ABI (application binary interface) stable and compatible. That's why any application targeting a lower iOS version needs to include Swift dylibs dependencies used by the framework. Use the SwiftRuntimeSupport NuGet package to automatically include required dylib dependencies into the resulting application package.
• Add SwiftSupport folder with signed dylibs, which is validated by the AppStore during the uploading process. The package should to be signed and distributed to the AppStore connect using Xcode tools, otherwise, it will be automatically rejected.

Note: This package works only on real devices. You won't be able to test your application on simulators with an iOS version lower than 12.2.

To use cmbSDK for barcode scanning with a mobile device without an MX mobile terminal, you need to install a license key. If the license key is missing, asterisks will appear instead of scanned results.

Contact your Cognex Sales Representative for information on how to obtain a license key, including 30-day trial licenses.

If you obtain cross platform license (one license for both platforms) implement an activation directly from the code when you create camera scanner:

if (param_deviceClass == ScannerDevice.PhoneCamera)
{
    //***************************************************************************************
    // Create a camera scanner (for either the built-in camera)
    //
    // NOTE: If we're scanning using the built-in camera of the mobile phone or tablet, 
    //       then the SDK requires a license key. 
    //       Refer to the SDK's documentation on obtaining a license key as well as the methods for
    //       passing the key to the SDK (in this example, we're relying on an entry in
    //       plist.info and androidmanifest.xml--there are also DeviceCamera methods where it can be passed
    //       as a parameter).
    //***************************************************************************************
    scannerControl.GetPhoneCameraDevice(param_cameraMode, ScannerPreviewOption.Defaults, true, "SDK_KEY");
}

Otherwise if you have different keys (key for iOS only and key for Android only) add these keys inside AndroidManifest.xml or Info.plist files.

For Android add the following line in the AndroidManifest.xml file of your application under the application tag:

<application>
        .....
     <meta-data android:name="MX_MOBILE_LICENSE" 
          android:value="YOUR_MX_MOBILE_LICENSE"/>
</application>

For iOS add it as a key with a value in the project specific Info.plist file:

<key>MX_MOBILE_LICENSE</key>
<string>Your license key</string>

1. When you build your UI considering that if you want to show partial screen you need to set size on scannerControl that represent the reader device and when you create camera scanner in constructor send false as input parameter for fullScreen. If you want to use full screen preview don't need to set any size on scannerControl and in constructor send true as input parameter for fullScreen (like in our sample app).
    
2. Set up the following event handlers to monitor the connection state of the scannerControl and receive information about the read code:

   // This is called when a MX-1xxx device has became available (USB cable was plugged, or MX device was turned on),
   // or when a MX-1xxx that was previously available has become unavailable (USB cable was unplugged, turned off due to inactivity or battery drained)
   public void OnAvailabilityChanged(object sender, ScannerAvailability availability)
   {
       ClearResult();
   
       if (availability == ScannerAvailability.Available)
       {
           ConnectToScannerDevice();
       }
       else if (availability == ScannerAvailability.Unavailable)
       {
           DisplayAlert("Device became unavailable", null, "OK");
       }
   }
   
   // The connect method has completed, here you can see whether there was an error with establishing the connection or not
   // (args: ScannerExceptions exception, string errorMessage)
   public void OnConnectionCompleted(object sender, object[] args)
   {
       // If we have valid connection error param will be null,
       // otherwise here is error that inform us about issue that we have while connecting to scanner
       if ((ScannerExceptions)args[0] != ScannerExceptions.NoException)
       {
           // ask for Camera Permission if necessary (android only, for iOS we handle permission from SDK)
           if ((ScannerExceptions)args[0] == ScannerExceptions.CameraPermissionException)
               RequestCameraPermission();
           else
           {
               Debug.WriteLine(args[1].ToString());
               UpdateUIByConnectionState(ScannerConnectionStatus.Disconnected);
           }
       }
   }
   
   // This is called when a connection with the scanner has been changed.
   // The scanner is usable only in the "Connected" state
   public void OnConnectionStateChanged(object sender, ScannerConnectionStatus status)
   {
       ClearResult();
   
       if (status == ScannerConnectionStatus.Connected)
       {
           // We just connected, so now configure the device how we want it
           ConfigureScannerDevice();
       }
   
       isScanning = false;
       UpdateUIByConnectionState(status);
   }
   
   // This is called after scanning has completed, either by detecting a barcode, canceling the scan by using the on-screen button or a hardware trigger button, or if the scanning timed-out
   public void OnReadResultReceived(object sender, List<ScannedResult> results)
   {
       ClearResult();
   
       foreach (ScannedResult item in results)
           scanResults.Add(item);
   
       isScanning = false;
       btnScan.Text = "START SCANNING";
   }

    

3. Create scanner device

Initialize a scanner device object for MX readers using the following factory method:

//***************************************************************************************
                // Create an MX-1xxx scanner  (note that no license key in needed)
                //***************************************************************************************
scannerControl.GetMXDevice();

The availability of the MX mobile terminal can change when the device turns on or off, or if the USB cable gets connected or disconnected. You can handle those changes using the following method from AvailabilityChanged event handler:

public void OnAvailabilityChanged(ScannerAvailability args)

You are recommended to use an MX mobile terminal to scan barcodes. However, cmbSDK also supports using the built-in camera of a mobile device. This includes the support of optional external aimers or illumination, and the customization of the live-stream preview's appearance.

To scan barcodes using the built-in camera of a mobile device, initialize the scanner device object using the scannerControl.GetPhoneCameraDevice method. The camera reader has several options when initialized. The following parameters are required:

• CameraMode
• PreviewOption
• FullScreen
• RegistrationKey

The ScannerCameraMode parameter is of type ScannerCameraMode enum and it accepts one of the values listed in the following table.

These modes provide the following default settings for the scanner:

• The zoom feature is available and a button to control it is visible on the live-stream preview (if displayed).
• The simulated hardware trigger (volume control buttons) is disabled.
• When StartScanning() is called, the decoding process is started.

Based on the selected mode, additional illumination options and behaviors are set, also listed in the table.

The ScannerPreviewOption parameter is of type ScannerPreviewOption enum, and is used to change the reader’s default values or override defaults derived from the selected ScannerCameraMode. You can specify the following options:

If the FullScreen parameter is set true, a full screen preview is used, otherwise partial screen preview is in use.

The RegistrationKey (optional) parameter is used to license your SDK with license key that you have

Examples:

Create a reader with no aimer and a full screen live-stream preview:

scannerControl.GetPhoneCameraDevice(ScannerCameraMode.NoAimer, ScannerPreviewOption.Defaults, true);

Create a reader with no aimer, no zoom button, and using a simulated trigger:

scannerControl.GetPhoneCameraDevice(ScannerCameraMode.NoAimer, ScannerPreviewOption.NoZoomButton | ScannerPreviewOption.HardwareTrigger, true);

From Android 6.0 and above you need to request permission from the user to access the built-in camera of the mobile device.

If the camera cannot be opened due to permission issues, the OnConnectionCompleted(sender, args) callback contains a ScannerException in the args parameter. You can check for this exception type and request permission.

public void OnConnectionCompleted(object sender, object[] args)
{
    // If we have valid connection error param will be null,
    // otherwise here is error that inform us about issue that we have while connecting to scanner
    if ((ScannerExceptions)args[0] != ScannerExceptions.NoException)
    {
        // ask for Camera Permission if necessary (android only, for iOS we handle permission from SDK)
        if ((ScannerExceptions)args[0] == ScannerExceptions.CameraPermissionException)
            RequestCameraPermission();

...

If camera permission is granted you can try to connect on scanner device again:

private async void RequestCameraPermission()
{
    var result = await Permissions.RequestAsync<Permissions.Camera>();

    // Check result from permission request. If it is allowed by the user, connect to scanner
    if (result == PermissionStatus.Granted)
    {
        scannerControl.Connect();
    }
    else
    {
        if (Permissions.ShouldShowRationale<Permissions.Camera>())
        {
            if (await DisplayAlert(null, "You need to allow access to the Camera", "OK", "Cancel"))
                RequestCameraPermission();
        }
    }
}

Before connecting, set the OnAvailabilityChanged, ConnectionStateChanged and ConnectionCompleted event handlers.

public void OnAvailabilityChanged(object sender, ScannerAvailability availability)
public void OnConnectionStateChanged(object sender, ScannerConnectionStatus status)
public void OnConnectionCompleted(object sender, object[] args)

Invoke the connect method after initializing the ScannerDevice.

// Before the scanner can be configured or used, a connection needs to be established
private void ConnectToScannerDevice()
{
    scannerControl.Connect();
}

Event handlers that we set before will be called with new ScannerDevice status information.

CmbSDK does not enable any symbologies by default for barcode reading with the built-in camera of the mobile device. You must enable all barcode symbologies your application needs to scan to achieve optimal scanning performance.

Individual symbologies can be enabled using the following method of the ScannerControl class:

public void SetSymbologyEnabled(Symbology symbology, bool enable)

All symbologies used for the symbology parameter in this method can be found in Symbology enum.

Examples

// Explicitly enable the symbologies we need
scannerControl.SetSymbologyEnabled(Symbology.Datamatrix, true);
scannerControl.SetSymbologyEnabled(Symbology.C128, true);

You can also use the same method to disable symbologies:

// Explicitly disable symbologies we know we don't need
scannerControl.SetSymbologyEnabled(Symbology.Codabar, false);

You can implement SymbologyEnabled event handler to check the result of the symbology change:

// SymbologyEnabled listener (args: Symbology symbology, bool isEnabled, string error)
public void OnSymbologyEnabled(object sender, object[] args)
{
    if ((string)args[2] != null)
        Debug.WriteLine("Failed to enable/disable " + args[0].ToString());
    else
        Debug.WriteLine(((Symbology)args[0]).ToString() + ((bool)args[1] ? " enabled" : " disabled"));
}

If your scanner device is equipped with illumination lights, you can control them using this DMCC:

scannerControl.SendCommand("SET LIGHT.INTERNAL-ENABLE ON");

You can control lights while scanning preview is active, or if you send this DMCC before starting the scanner you will set the initial value for lights.

If the built-in camera of a mobile device is used as the reader device, you can configure zoom levels and how they are used. There are three zoom levels:

• normal: not zoomed (100%)
• level 1 zoom (150% on Android by default)
• level 2 zoom (300% on Android by default)

The SET CAMERA.ZOOM-PERCENT [100-MAX] [100-MAX] command is for configuring how far the two levels zoom in percentage. 100 is not zoomed and MAX (goes up to 1000) zooms as far as the device is capable of. The first argument is used for setting level 1 zoom, and the second for level 2 zoom.

You can check the current zoom setting with the GET CAMERA.ZOOM-PERCENT command, which returns two values: level 1 and level 2 zoom.

Example

scannerControl.SendCommand("SET CAMERA.ZOOM-PERCENT 250 500");

GET/SET CAMERA.ZOOM 0-2 is another command that sets the zoom level or returns the actual setting. Possible values for the SET command are:

• 0 - normal (not zoomed)
• 1 - level 1 zoom
• 2 - level 2 zoom

You can call this command before or even during scanning, and the zoom goes up to the configured level. If scanning is finished, the value is reset to normal behavior (0).

Example

scannerControl.SendCommand("SET CAMERA.ZOOM 2");

When using the mobile device's camera, cmbSDK allows you to see the camera preview inside a preview container or in full screen. This preview also contains a customizable overlay. The cmbSDK camera overlay features buttons for zooming, flashing and closing the scanner, and a progress bar indicating the scan timeout.

To use the legacy camera overlay originally used in cmbSDK v2.0.x and ManateeWorks SDK, use this before initializing the ScannerDevice:

private void CreateScannerDevice()
{
    
    if (param_deviceClass == ScannerDevice.PhoneCamera)
    {
        scannerControl.SetOverlay(ScannerOverlay.LEGACY);

        scannerControl.GetPhoneCameraDevice(ScannerCameraMode.NoAimer, ScannerPreviewOption.Defaults, true);
    }

When using the cmbSDK overlay:

1. Copy the layout files from the Resources/Android/layout directory into your Android platform specific project and modify them. Use cmb_scanner_partial_view.xml if scanning is started inside a container (partial view), and use cmb_scanner_view.xml if scanning is started in full screen. Same for iOS, copy the xib files from the Resources/iOS directory into your iOS platform specific project and modify them. Use CMBScannerPartialView.xib if scanning is started inside a container (partial view), and use CMBScannerView.xib if scanning is started in full screen.
   
2. Modify the layout and xib according to your needs. For example, you can change the sizes, positions or color of the views, remove views and add your own views, like an overlay image.

Both the cmbSDK and the legacy overlay allow you to change the images used on the zoom and flash buttons if your images have the same name as the names cmbSDK uses. You can find the images and names used in cmbSDK in the Resources/drawable-mdpi and drawable-hdpi directories for Android and Resources/MWBScannerImages.xcassets for iOS.

Both the cmbSDK and the legacy overlay allow you to change the color and width of the rectangle that is displayed when a barcode is detected. These changes need to be done inside ConfigureScannerDevice() method (after we have valid connection to scanner device).

Example:

private void ConfigureScannerDevice()
{
   scannerControl.SetLegacyOverlayLocationLine(255, System.Drawing.Color.Yellow, 6.0f, true);

...

Cognex scanning devices implement DataMan Control Commands (DMCC) for configuring and controlling the device. Every feature of the device can be controlled using this text-based language. The API provides a method for sending DMC commands to the device. Commands exist both for setting and querying configuration properties. DMC commands are same for all platforms and frameworks.

The Appendix includes the complete DMCC reference for the camera reader.

The following examples show different DMCC sent to the device for more advanced configuration.

Examples

//Change the scan direction to omnidirectional 
scannerControl.SendCommand("SET DECODER.1D-SYMBOLORIENTATION 0");
//Change live-stream preview's scanning timeout to 10 seconds 
scannerControl.SendCommand("SET DECODER.MAX-SCAN-TIMEOUT 10");

You can also set ResponseReceived event handler to receive response from the send command:

// ResponseReceived listener after we send DMCC command (args: string payload, string error, string dmcc)
public void OnResponseReceived(object sender, object[] args)
{
    if ((string)args[1] != null)
        Debug.WriteLine("Failed to execute DMCC");
    else
        Debug.WriteLine("Response for " + (string)args[2] + ": " + (string)args[0]);
}

CmbSDK includes a method for resetting the device to its default settings. In case of an MX mobile terminal, the default setting are the saved configurations. In case of a built-in camera, the default settings are the defaults identified in the Appendix, where no symbologies are enabled.

To reset the device send this DMCC:

scannerControl.SendCommand("CONFIG.DEFAULT");

When using an MX mobile terminal, there are three states that we can distinguish:

• Factory defaults
• Saved configuration: when there were different configurations set on the device and CONFIG.SAVE DMCC was called.
• Session configuration: when you make changes on the saved configuration, the changes are valid until the MX Mobile Terminal is rebooted. If it is rebooted, it has the saved configuration state.

With a properly configured reader, you are ready to scan barcodes. This is simply accomplished by calling the StartScanning() method from your scannerControl. What happens next is based on the type of ScannerDevice and how it has been configured. Generally:

• If using an MX terminal, press a trigger button on the device to turn the scanner on and read a barcode.
• If using the camera reader, the cmbSDK starts the camera, displays the configured live-stream preview, and begins analyzing the frames from the video stream, looking for a configured barcode symbology.

Scanning stops under one of the following conditions:

• The reader found and decoded a barcode.
• The user released the trigger or pressed the stop button on the live-stream preview screen.
• The camera reader timed out without finding a barcode.
• The application program calls the StopScanning() method.

When a barcode is decoded successfully, you will receive a ScannedResult list in your ReadResultReceived event:

// This is called after scanning has completed, either by detecting a barcode, canceling the scan by using the on-screen button or a hardware trigger button, or if the scanning timed-out
public void OnReadResultReceived(object sender, List<ScannedResult> results)

To simply display a ScannedResult after scanning a barcode:

public void OnReadResultReceived(object sender, List<ScannedResult> results)
{
    if (results.Count > 0)
    {
        ScannedResult readResult = results[0];

        lblCode.Text = readResult.ResultCode;
    }
}

There may be cases when a device disconnects due to low battery condition or manual cable disconnection. These cases can be detected in the ConnectionStateChanged event handler.

After returning to your application from inactive state, the reader device remains initialized but not connected. There is no need for reinitializing the SDK but you need to re-connect. For iOS we are doing that in ScannerControl renderer while for Android need to be done manually when page is resumed:

// When an page is disappeared, the connection to the scanning device needs
// to be closed; thus when we are resumed (Appear this page again) we
// have to restore the connection (assuming we had one).
// This is used for android only.
// For iOS we use Observer that is created in ScannerControl class in iOS platform specific project
//----------------------------------------------------------------------------
if (Device.RuntimePlatform == Device.Android && await Permissions.CheckStatusAsync<Permissions.Camera>() == PermissionStatus.Granted)
{
    ConnectToScannerDevice();
}