MainActivity.kt

class MainActivity : AppCompatActivity() {
  
  override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        Fritz.configure(this)

        cameraView.addFrameProcessor { frame ->
             //This returns a frame, which cann be used to retrieve the preview                    
        }
    }  
}