Getting exception while navigating between fragments after image capture (CameraX)

Question

I am using Camerax to capture images. but I want to navigate to another fragment after camera capture success.

I am using this code.

  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")
                        val capturedFileArray = ArrayList<GalleryItems>()
                        capturedFileArray.add(
                            GalleryItems("image",photoFile.absolutePath,false)
                        )
                        val bundle = Bundle()
                        bundle.putParcelableArrayList("selected_images", capturedFileArray)
                        findNavController().navigate(
                            R.id.action_cameraFragment_to_submitPostFragment,
                            bundle
                        )
                    }
                })

The image is captured and saved successfully. but gets an error on the navigation section

E/AndroidRuntime: FATAL EXCEPTION: pool-2-thread-1
    Process: com.example.travelinsta, PID: 27221
    android.util.AndroidRuntimeException: Animators may only be run on Looper threads
        at android.animation.ValueAnimator.start(ValueAnimator.java:1035)
        at android.animation.ValueAnimator.start(ValueAnimator.java:1089)
        at android.animation.ObjectAnimator.start(ObjectAnimator.java:852)
        at androidx.navigation.ui.AbstractAppBarOnDestinationChangedListener.setActionBarUpIndicator(AbstractAppBarOnDestinationChangedListener.java:132)
        at androidx.navigation.ui.AbstractAppBarOnDestinationChangedListener.onDestinationChanged(AbstractAppBarOnDestinationChangedListener.java:110)
        at androidx.navigation.NavController.dispatchOnDestinationChanged(NavController.java:504)
        at androidx.navigation.NavController.navigate(NavController.java:1142)
        at androidx.navigation.NavController.navigate(NavController.java:944)
        at androidx.navigation.NavController.navigate(NavController.java:877)
        at androidx.navigation.NavController.navigate(NavController.java:863)
        at com.example.travelinsta.ui.camera.CameraFragment$updateCameraUi$2$$special$$inlined$let$lambda$1.onImageSaved(CameraFragment.kt:230)
        at androidx.camera.core.ImageCapture$2.onImageSaved(ImageCapture.java:843)
        at androidx.camera.core.ImageSaver.lambda$postSuccess$1$ImageSaver(ImageSaver.java:299)
        at androidx.camera.core.-$$Lambda$ImageSaver$29vxg6qyjKwPRXgWrIwgYVInWKE.run(Unknown Source:4)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:764)

Please help. thanks in advance.

Answer 1

call findNavController().navigate in UI Thread e.g. using below

            new Handler(Looper.getMainLooper()).post(new Runnable(){
                public void run(){
                    findNavController().navigate(
                            R.id.action_cameraFragment_to_submitPostFragment,
                            bundle
                    );
                }
            });

or if you are in Activity you can just use runOnUiThread(new Runnable(){...});

edit: sorry for Java code, I've just realized that your is in Kotlin

Handler(Looper.getMainLooper()).post {
    findNavController().navigate(
        R.id.action_cameraFragment_to_submitPostFragment,
        bundle
    )
}