Android SnackBar crashes on touch with design support library 23.0.0

Question

After upgrading to Design Support Library 23.0.0 and build SDK 23, my application crashes when I try to dismiss a Snackbar:

java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.MotionEvent.getAction()' on a null object reference
            at android.support.design.widget.AppBarLayout$Behavior.onInterceptTouchEvent(AppBarLayout.java:729)
            at android.support.design.widget.AppBarLayout$Behavior.onInterceptTouchEvent(AppBarLayout.java:629)
            at android.support.design.widget.CoordinatorLayout.performIntercept(CoordinatorLayout.java:357)
            at android.support.design.widget.CoordinatorLayout.onInterceptTouchEvent(CoordinatorLayout.java:409)

I haven't changed anything since the update and I use the only way that I know off for showing a Snackbar:

Snackbar.make(rootView, getString(R.string.error_no_permissions),Snackbar.LENGTH_LONG).show();

There is an issue reported for NPE on CoordinatorLayout that could be related: CoordinatorLayout NullPointerException in onTouchEvent but I still can't find a workaround for my situation. I've tried this possible solution but still no luck...

EDIT: Turns out the solution is (as @NikolaDespotoski suggested) overriding the default AppBarLayout.Behavior

public class AppBarLayoutBehavior extends AppBarLayout.Behavior {

    @Override
    public boolean onInterceptTouchEvent(CoordinatorLayout parent, AppBarLayout child,
            MotionEvent ev) {
        return !(parent != null && child != null && ev != null) || super
                .onInterceptTouchEvent(parent, child, ev);
    }
}

...and use it in our AppBarLayout

((CoordinatorLayout.LayoutParams) findViewById(R.id.appbar).getLayoutParams())
                .setBehavior(new AppBarLayoutBehavior());

If you look at the ticket which you've linked, you might notice it's marked as "FutureRelease" which means that issue has been fixed, it just hasn't been released yet. Judging from the comment made on Thursday, August 20th "We're looking to get a hotfix out ASAP", hopefully there will be a release soon to fix this problem. Otherwise, it seems like the best course of action may be to go back to api 22, or ignore the issue until the fix is released. — Joseph Roque
Looks like it, but I'm afraid the Snackbar issue won't get fixed since the suggested workaround doesn't solve it. Anyway, I guess you're right, it would be best if I go back to design support 22.2.1 for production and build SDK 22, but that's a problem since I started preparing my app for Android M... — Bojan Ilievski
Well, you could continue to prepare for 23.0.0 and ignore the error for now until a fix is released, which will hopefully be before Android M is actually released to users. That way you aren't falling behind in that sense. And if it does come out, you'll just have to build for 22 — Joseph Roque
How about mitigating invalid/null motion events? Inherit AppBarLayout and just avoid streaming null motion events to the super implementation in onInterceptTouchEvent method, until google releases fix for this. — Nikola Despotoski
This is what I was looking for. Thanks @NikolaDespotoski Turns out I only needed to override the AppBarLayout.Behavior onInterceptTouchEvent and set it to my AppBarLayout... — Bojan Ilievski

Nikola Despotoski Nikola Despotoski · Accepted Answer · 2015-08-24T23:02:33

Another fix for the time being is overriding onInterceptTouchEvent of the AppBarLayout.Behavior and invalid or null MotionEventbeing discarded, just to mitigate the crash in the super implementation.

That would resound as:

@Override
public boolean onInterceptTouchEvent(CoordinatorLayout parent, AppBarLayout child, MotionEvent ev){
   return ev != null ? super.onInterceptTouchEvent(parent,child, ev) : true;
}

For the MotionEvent that was probably invalid, we won't do anything about it, so we make the inherited Behavior thinks we have handled it.

Android SnackBar crashes on touch with design support library 23.0.0

3 Answers