1. First of all make sure that your application supports Kotlin. cmbSDK Toolkit can't be used in applications that don't support Kotlin.
2. Download the Cognex Mobile Barcode SDK for Android and cmbSDK Toolkit from the Cognex Mobile Barcode Scanner Solutions page.
3. Start Android Studio and add the AAR files as a modules to your project. Starting from Android Studio v4.2.1 and later, .AAR files can't be imported directly as modules. You need to import the Gradle or Eclipse project:
   1. Right-click your app module, select New > Module > Import.

   2. In the Source directory field browse the cmbsdktoolkit directory that contains the build.gradle file and the cmbsdktoolkit.aar file inside. In the Module name field you should see :cmbsdktoolkit, and click Finish. In the same way import cmbSDK.

4. After the new modules are available, right-click your app module, select the Open Module Settings, and choose the Dependencies tab.

5. Click the + sign at the top of the Declared Dependencies dialog box and select the 3 Module dependency.
6. Select cmbsdktoolkit and cmbsdklib-release from the popup window and click OK, making them available under the Dependencies tab. Also com.squareup.moshi:moshi-kotlin:1.13.0 dependency is needed to be linked inside your project because of the cmbsdktoolkit module.
   
   
7. Sync your project with the latest changes in the gradle files. Your application build.gradle should contain these dependencies:
   

parentFragmentManager.beginTransaction()
  .replace(
      R.id.fragment_holder,
      SymbologySettingsFragment.newInstance(readerDevice),
      SymbologySettingsFragment.TAG
  )
  .addToBackStack(SymbologySettingsFragment.TAG)
  .commit()

If the reader device is not connected or disconnected while this fragment is shown, symbology settings fragment will be closed and removed from the back stack with warning message.

First we need to add required bluetooth permissions in the application manifest file:

    <!-- Request legacy Bluetooth permissions on older devices. -->
    <uses-permission
        android:name="android.permission.BLUETOOTH"
        android:maxSdkVersion="30" />
    <uses-permission
        android:name="android.permission.BLUETOOTH_ADMIN"
        android:maxSdkVersion="30" />
    <uses-permission
        android:name="android.permission.ACCESS_FINE_LOCATION"
        android:maxSdkVersion="30"
        tools:ignore="CoarseFineLocation" />
    <!---->

    <uses-permission
        android:name="android.permission.BLUETOOTH_SCAN"
        android:usesPermissionFlags="neverForLocation"
        tools:targetApi="s" />
    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />

Inside the cmbsdktoolkit module, bluetooth pairing functionality is implemented as fragment that can be attached from any fragment manager.

This fragment has two optional input parameters:

1. connectAfterPairing - true means bluetooth reader device will be created and connection to it is performed automatically after successful pairing. If you use false, you can start the process manually to create and connect to bluetooth reader device. Default is true
2. awaitUserApprovalOnConnect - true means that screen where user need to allow connection to the bluetooth reader device to be completely finished will be shown. If false is set no interaction from user is needed. Default is true

parentFragmentManager.beginTransaction()
  .replace(
      R.id.fragment_holder,
      BluetoothPairingFragment.newInstance(),
      BluetoothPairingFragment.TAG
  )
  .addToBackStack(BluetoothPairingFragment.TAG)
  .commit()

The parent activity need to implement BluetoothPairingFragmentListener:

class MainActivity : AppCompatActivity(), BluetoothPairingFragmentListener

• onBluetoothDevicePaired(device: BluetoothDevice) - If connectAfterPairing input param is set to true, connection to the bluetooth device will be performed automatically after successful pairing. If it is set to false, then you can start the connection process.
   

  override fun onBluetoothDevicePaired(device: BluetoothDevice) {
          // In BluetoothPairingFragment as input param we've set connectAfterPairing to true, which means
          // that connection to the bluetooth device will be performed automatically after successful pairing.
          // If we set that to false, from here we can start the connection process
  }

   

• onBluetoothDeviceConnectionFailed(error: Throwable) - The throwable error object contains message that explains the cause why the connection has failed
   

  override fun onBluetoothDeviceConnectionFailed(error: Throwable) {
          Snackbar.make(
              findViewById(R.id.fragment_holder),
              getString(R.string.bluetooth_pairing_error, error.localizedMessage),
              Snackbar.LENGTH_LONG
          ).show()
  }

   

• onBluetoothReaderDeviceConnected(reader: BluetoothReaderDevice) - There is a valid connection to the bluetooth reader device that is received as input parameter. You can start to configure the reader device or to scan. Do not forget to close and remove the BluetoothPairingFragment from the back stack if needed.
   

  override fun onBluetoothReaderDeviceConnected(reader: BluetoothReaderDevice) {
          reader.setReaderDeviceListener(this)
  
          readerDevice = reader
  
          clearAllFragments()
          configureReaderDevice()
  
  }