NPE in draw() when returning to Fragment with animation

Created by: WonderCsabo

If i add custom animations when opening a Fragment from a Fragment which the SlidingUpPanelLayout is in, i get NPE in the draw() method when returning to the Fragment.

java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getRight()' on a null object reference
   at com.sothree.slidinguppanel.SlidingUpPanelLayout.draw(SlidingUpPanelLayout.java:1261)
   at android.view.View.updateDisplayListIfDirty(View.java:15174)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3585)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ViewGroup.recreateChildDisplayList(ViewGroup.java:3593)
   at android.view.ViewGroup.dispatchGetDisplayList(ViewGroup.java:3573)
   at android.view.View.updateDisplayListIfDirty(View.java:15134)
   at android.view.ThreadedRenderer.updateViewTreeDisplayList(ThreadedRenderer.java:281)
   at android.view.ThreadedRenderer.updateRootDisplayList(ThreadedRenderer.java:287)
   at android.view.ThreadedRenderer.draw(ThreadedRenderer.java:322)
   at android.view.ViewRootImpl.draw(ViewRootImpl.java:2615)
   at android.view.ViewRootImpl.performDraw(ViewRootImpl.java:2434)
   at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2067)
   at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1107)
   at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6013)
   at android.view.Choreographer$CallbackRecord.run(Choreographer.java:858)
   at android.view.Choreographer.doCallbacks(Choreographer.java:670)
   at android.view.Choreographer.doFrame(Choreographer.java:606)
   at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:844)
   at android.os.Handler.handleCallback(Handler.java:739)
   at android.os.Handler.dispatchMessage(Handler.java:95)
   at android.os.Looper.loop(Looper.java:148)
   at android.app.ActivityThread.main(ActivityThread.java:5417)
   at java.lang.reflect.Method.invoke(Native Method)
   at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
   at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

This happens because onMeasure is not called yet, hence the mSlideableView field is not set.

We could add an if to guard against NPE in the draw() method.