It is as easy as implementing a listener and calling another activity.

• Implement or create an instance of DocumentScannerEventReceiver implementation.

Java

// Java
 @Override
 public void onProcessingCompleted(Context context, Document document) {
     // Background document processing has successfully finished
          document.getDocumentImage();
 }
 @Override
 public void onProcessingFailed(Context context, ScannerError error) {
 // Journey failed check Scanner Error possibilities, in JavaDocs.
 }
 @Override
 public void onProcessingCancelled(Context context, ScannerError error) {
 // Journey was cancelled by user input (onBackPresed)
 }

Kotlin

// Kotlin
 private val response = object : DocumentScannerEventReceiver() {
         override fun onProcessingCompleted(context: Context, result: Document) {
             // If Scan was successful document object will be returned here.
             // Document object contains document image and minimal clarification of the document if document was recognised.
         }

        override fun onProcessingCancelled(context: Context, scannerError: ScannerError) {         
            // Returned when customer canceled journey, most probably onBack click.     }     

        override fun onProcessingFailed(context: Context, errorCode: ScannerError) {         
           // Failure from which we could not recover.     
        } 
    }

• Register your implementation using DocumentScannerService

//Register before call
DocumentScannerService.registerEventReceiver(context, implementation);
 
//Unregister after call
DocumentScannerService.unregisterEventReceiver(context, implementation); 

• Create an intent with destination activity is DocumentScannerActivity and start it.

// Create intent to start scanner activity
Intent myIntent = new Intent(MyActivity.this, DocumentScannerActivity.class);
startActivity(myIntent);