NullPointerException - Drawable.setBounds - probably due to fragment transitions

问题

I'm getting following error and I don't know why (this error is VERY RARE and not reproducable for me):

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.graphics.drawable.Drawable.setBounds(int, int, int, int)' on a null object reference
at android.widget.ImageView.animateTransform(ImageView.java:1126)
at android.transition.ChangeImageTransform$2.set(ChangeImageTransform.java:64)
at android.transition.ChangeImageTransform$2.set(ChangeImageTransform.java:61)
at android.animation.PropertyValuesHolder.setAnimatedValue(PropertyValuesHolder.java:938)
at android.animation.ObjectAnimator.animateValue(ObjectAnimator.java:952)
at android.animation.ValueAnimator.animationFrame(ValueAnimator.java:1207)
at android.animation.ValueAnimator.doAnimationFrame(ValueAnimator.java:1248)
at android.animation.ValueAnimator$AnimationHandler.doAnimationFrame(ValueAnimator.java:659)
at android.animation.ValueAnimator$AnimationHandler.run(ValueAnimator.java:682)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:549)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:211)
at android.app.ActivityThread.main(ActivityThread.java:5321)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1016)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:811)

I think it has to do with the android Fragment and Activity transitions, but I'm not sure... The above is the complete stacktrace.

Maybe interesting, I'm using the support-library

Does anyone have an idea where this comes from and how I can prevent it?

EDIT

As written in the comments:

• I don't know from which code block this exception comes from
• I don't animate anything myself
• I assume, this problem comes from transactions between fragments (the only animations I use in my app)

EDIT2

I did not know that I have to make sure an ImageView does have a content. This may lead to the above error, an ImageView that does not have an image yet.

回答1:

A Fragment or Activity transition is trying to animate an ImageView which has no drawable set. Ensure you always have a Drawable set for your ImageView when you animate it with ChangeImageTransform (or disable this kind of animation)

回答2:

I followed answer made by @BladeCoder in this thread. His solution was just one part if you used Universal Image Loader.

After adding placeholder to ImageView, you need also to put some image or color (depends of your needs) to XML.

来源：https://stackoverflow.com/questions/31381385/nullpointerexception-drawable-setbounds-probably-due-to-fragment-transitions