Android “Only the original thread that created a view hierarchy can touch its views.”

Question

I\'ve built a simple music player in Android. The view for each song contains a SeekBar, implemented like this:

public class Song extends Activity implement         


        

Answer 1

If you are within a fragment, then you also need to get the activity object as runOnUIThread is a method on the activity.

An example in Kotlin with some surrounding context to make it clearer - this example is navigating from a camera fragment to a gallery fragment:

// Setup image capture listener which is triggered after photo has been taken
imageCapture.takePicture(
       outputOptions, cameraExecutor, object : ImageCapture.OnImageSavedCallback {

           override fun onError(exc: ImageCaptureException) {
           Log.e(TAG, "Photo capture failed: ${exc.message}", exc)
        }

        override fun onImageSaved(output: ImageCapture.OutputFileResults) {
                        val savedUri = output.savedUri ?: Uri.fromFile(photoFile)
                        Log.d(TAG, "Photo capture succeeded: $savedUri")
               
             //Do whatever work you do when image is saved         
             
             //Now ask navigator to move to new tab - as this
             //updates UI do on the UI thread           
             activity?.runOnUiThread( {
                 Navigation.findNavController(
                        requireActivity(), R.id.fragment_container
                 ).navigate(CameraFragmentDirections
                        .actionCameraToGallery(outputDirectory.absolutePath))
              })