IssueTracker

All latest versions affected:

implementation 'androidx.viewpager2:viewpager2:1.0.0' // or 1.1.0-alpha01
implementation 'androidx.swiperefreshlayout:swiperefreshlayout:1.1.0' // or 1.2.0-alpha01

See attached video. You can try running the sample app and simply drag the bottom sheet. Sometimes - usually when the thumb ends up above the actual bottom sheet header - the viewpager allows horizontal swiping in the middle of a vertical swiping operation. This causes very bad UX. Users are complaining about the instability of the swiping functionality. Please advise!

Please note that the sample demonstrates this issue with SwipeRefreshLayout. I have confirmed this problem without it too.

Nothing fancy about the viewpager fragments:

<CoordinatorLayout>
    <SwipeRefreshLayout>
       <SomeView />
    </SwipeRefreshLayout>
    <NestedScrollView
        app:layout_behavior="com.google.android.material.bottomsheet.BottomSheetBehavior">
        <LinearLayout>
            <TextView />
            <TextView />
        </LinearLayout>
    </NestedScrollView>
</CoordinatorLayout>

Now, if I replace the BottomSheetBehavior with the following class, the unwanted glitch described above disappears. But, then I'm not able to swipe between the viewpager tabs :P. Without a SwipeRefreshLayout, however, this trick would actually work (it seems).

public class SimpleBottomSheetBehavior<V extends View> extends BottomSheetBehavior<V> {
    public SimpleBottomSheetBehavior() {
    }

    public SimpleBottomSheetBehavior(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    @Override
    public boolean onInterceptTouchEvent(@NonNull @NotNull CoordinatorLayout parent, @NonNull @NotNull V child, @NonNull @NotNull MotionEvent event) {
        boolean intercepted = super.onInterceptTouchEvent(parent, child, event);

        int action = event.getActionMasked();
        if (action == MotionEvent.ACTION_MOVE) {
            parent.requestDisallowInterceptTouchEvent(true);
        }

        return intercepted;
    }
}