android – Crash in Activity Transitions with SharedElement-ThrowExceptions

Exception or error:

I’m using Activity transitions from a ViewPager (in the calling activity) with a shared element and content transitions as well. I’m getting this crash when re-entering to the calling activity:

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.os.ResultReceiver.send(int, android.os.Bundle)' on a null object reference
  at android.app.EnterTransitionCoordinator.sendSharedElementDestination(EnterTransitionCoordinator.java:199)
  at android.app.EnterTransitionCoordinator.viewsReady(EnterTransitionCoordinator.java:123)
  at android.app.EnterTransitionCoordinator$2.onPreDraw(EnterTransitionCoordinator.java:148)
  at android.view.ViewTreeObserver.dispatchOnPreDraw(ViewTreeObserver.java:895)
  at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2153)
  at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1180)
  at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6558)
  at android.view.Choreographer$CallbackRecord.run(Choreographer.java:777)
  at android.view.Choreographer.doCallbacks(Choreographer.java:590)
  at android.view.Choreographer.doFrame(Choreographer.java:560)
  at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:763)
  at android.os.Handler.handleCallback(Handler.java:739)
  at android.os.Handler.dispatchMessage(Handler.java:95)
  at android.os.Looper.loop(Looper.java:145)
  at android.app.ActivityThread.main(ActivityThread.java:5832)
  at java.lang.reflect.Method.invoke(Native Method)
  at java.lang.reflect.Method.invoke(Method.java:372)
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1399)

Also, Once going back, the screen begins to flicker continuously with a white screen flashing in and out.

Here are my Transition flags:

<item name="android:windowContentTransitions">true</item>
<item name="android:windowActivityTransitions">true</item>
<item name="android:windowAllowReturnTransitionOverlap">false</item>

I tried setting Enter/Exit transitions both on the Calling and Called activity but no luck.

How to solve:

Try to get fragment from FragmentManager:

fragmentManager.findFragmentByTag("android:switcher:" + R.id.viewPager + ":" + position)

If fragment is null, try creating a new fragment.

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