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androidactionbarsherlock

To use getSherlockActivity() or getActivity() or other?

I have an Android app with TabManager. Due to change of Android API, I need to upgrade my app for Activity to contain the Fragment. To provide backward compatibility, I use ActionBarSherlock.

My App is working fine. However, looking at the Google Play Developer Console, there is always few crash reports on "java.lang.NullPointerException" on the line with getSherlockActivity(), I think only less than 0.1% out of total users are affected.

For example, 

// Example 1    
File file = new File(getSherlockActivity().getCacheDir(), "filename");
// Example 2
getSherlockActivity().setSupportProgressBarIndeterminateVisibility(false);

My question: 1. Should I change all the getSherlockActivity() to getActivity()? Or under certain rule, it is mandatory to use one of them? 2. What is the difference between them?

Thanks a lot.

Solution

  • The only difference is that with getSherlockActivity () you get the result of getActivity() but casted as a SherlockActivity. This allows to get access to the ABS specific apis.

    If you just need something that is general enough to be in the Activity class, just use getActivity(). It will highlight this, otherwise highlight the fact that you use something that is ABS specific using getSherlockActivity ().

    The NPE can come from :

    • using getActivity() (or siblings...) before onAttach has been executed
    • using getActivity() (or siblings...) after onDetach has been executed

    So the solution is to check if your fragment is attached before using its activity : 

    if( isAttached() ) {
   getActivity()....
}