java.lang.NullPointerException on clearAnimation()

Question

How this crash is possible? It works 99% of the time and sometimes there is this crash...

Caused by java.lang.NullPointerException
Attempt to invoke virtual method 'void android.view.View.clearAnimation()' on a null object reference
com.XXX.VerticalPagerFragment.onViewPagerTouchDown

private void onViewPagerTouchDown() {
        if (isAdded()) {
            mPageIndicatorLayout.clearAnimation(); <<< CRASH
            ...
        }
    }

Object mPageIndicatorLayout is mapped with butterknife:

@BindView(R2.id.page_indicator_layout)
    View mPageIndicatorLayout;

This above method is called from this viewpager listener:

@Override
                public void onPageScrollStateChanged(int state) {
                    super.onPageScrollStateChanged(state);
                    if (isAdded()) {
                        if (state != ViewPager2.SCROLL_STATE_IDLE) {
                            onViewPagerTouchDown(); <<< HERE

                        } else {
                            onViewPagerTouchUp();
                        }
                    }
                }

I can't absolutely understand how this crash can occur in this context? Have you got an ideas?

Thank you very much!

May be it relates to fragment lifecycle, try to remove listener before view is destroyed. — Bracadabra, Dec 21 '19 at 09:14
Seems like mPageIndicatorLayout is getting null...try kotlin synthetics or findViewById — Quantum_VC, Dec 21 '19 at 09:20
mPageIndicatorLayout.post{ mPageIndicatorLayout.clearAnimation() } — Deepak Ror, Dec 21 '19 at 09:38
My guess is that: 1. Your layout and pager are not in the right view hierarchy which can be causing the view to be never inflated 2. Make sure pager and the view are attached to the same parent `ViewGroup` 3. Passing the view reference inside the call back it would be that you're leaking the view's reference intentionally, so I would be careful with that — HawkPriest, Dec 21 '19 at 09:43

java.lang.NullPointerException on clearAnimation()

0 Answers0