My Application consist of 4 fragment as tabs being loaded inside a parent Fragment using FragmentPagerAdapter
.
The problem is when I run the app and press back and re-open the app I receive this error log:
FATAL EXCEPTION: main
java.lang.NullPointerException: Attempt to invoke virtual method 'android.os.Handler android.support.v4.app.FragmentHostCallback.getHandler()' on a null object reference
at android.support.v4.app.FragmentManagerImpl.ensureExecReady(FragmentManager.java:1949)
at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1965)
at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:620)
at android.support.v4.app.FragmentPagerAdapter.finishUpdate(FragmentPagerAdapter.java:143)
at android.support.v4.view.ViewPager.setAdapter(ViewPager.java:513)
...
the line of code inside parent Fragment is:
viewPager.setAdapter(adapter);
tabLayout.setupWithViewPager(viewPager);
and ViewPage
and Adapter
both are not null!!
I have to mention that all my Fragment
s lifecycle is being managed and the null issue is happening inside the adapter!, and the same Adapter is working fine when I use an Activity
as parent instead of Fragment
!!!
After a lot of research, it looks like it is a support library issue:
Activity with fragment and ViewPager crashesh on configuration change
Android Support Library issue 24.1.0
I also found this answer, but it looks unusual adding a flag to my code:
I override the finishUpdate
method of my FragmentPagerAdapter
like this and problem solved for now!
@Override
public void finishUpdate(ViewGroup container) {
try{
super.finishUpdate(container);
} catch (NullPointerException nullPointerException){
System.out.println("Catch the NullPointerException in FragmentPagerAdapter.finishUpdate");
}
}
any better answer? please let me know...