mego | The MS Exchange meeting organizer

Dalvik keeps all Thread references in the runtime so your thread will keep running unless it is terminated or completes (some reference). So depending on where you start your thread, you may be creating more than one.

In your case Your thread execution is not completed and you change the fragment so your getActivity() will be null.

The solution is before getActivity(), check isAdded() is true or not, if not true, that means the fragment is already detached, call to getActivity() will return null.

Remember in the Thread, everywhere before you call getActivity(), you'd better to check isAdded() again, because user may exit the activity at anytime during the Thread is executing.

Other Solution

I am not sure but you can achieve by initialize Context globally and you that context in your thread.