Question

I am getting null while calling getSherlockActivity();

This is because the Activity is finished or killed

I could not come up with a solution to avoid in my case:

This SherlockActivity has a ViewPager with 4 Tabs.

adapter = new PagerAdapter((SherlockFragmentActivity) this, mViewPager);
adapter.addTab(actionBar.newTab(), Frag1.class, bundle);
adapter.addTab(actionBar.newTab(), Frag2.class, bundle);
adapter.addTab(actionBar.newTab(), Frag3.class, bundle);
adapter.addTab(actionBar.newTab(), Frag4.class, bundle);

When this Activity is launched, all the Tabs(Fragments) have an AsyncTask which uses getSherlockActivity() in doInBackground.

So, for all the AsyncTasks to complete, it takes around 3-5 secs, meanwhile if i press back and finish this Activity, the Last fragment Frag4 which didn’t yet started its AsyncTask(might be queued) tries for getSherlockActivity() and gets crashed.

I could just use a Try-Catch block and solve this, but is there a way i can tell the Fragments If the parent Activity is dead, stop all your background tasks etc.. something like that?

Thank You

Answer 1

Just call each fragment’s AsyncTask.cancel() in the Activity onDestroy() callback. That way, the asynctasks aren’t going to perform anything based on the destroyed Activity context.