Finishing current activity from a fragment

You should use getActivity() method in order to finish the activity from the fragment.

getActivity().finish();

Well actually...

I wouldn't have the Fragment try to finish the Activity. That places too much authority on the Fragment in my opinion. Instead, I would use the guide here: http://developer.android.com/training/basics/fragments/communicating.html

Have the Fragment define an interface which the Activity must implement. Make a call up to the Activity, then let the Activity decide what to do with the information. If the activity wishes to finish itself, then it can.

When working with fragments, instead of using this or refering to the context, always use getActivity(). You should call

Java

getActivity().finish();

Kotlin

activity.finish()

to finish your activity from fragment.

As mentioned by Jon F Hancock, this is how a fragment can 'close' the activity by suggesting the activity to close. This makes the fragment portable as is the reason for them. If you use it in a different activity, you might not want to close the activity.

Code below is a snippet from an activity and fragment which has a save and cancel button.

PlayerActivity

public class PlayerActivity extends Activity 
    implements PlayerInfo.PlayerAddListener {

    public void onPlayerCancel() {
       // Decide if its suitable to close the activity, 
       //e.g. is an edit being done in one of the other fragments?
       finish();
    }
}

PlayerInfoFragment, which contains an interface which the calling activity needs to implement.

public class PlayerInfoFragment extends Fragment {
   private PlayerAddListener callback; // implemented in the Activity

   @Override
   public void onAttach(Activity activity) {
     super.onAttach(activity);
     callback= (PlayerAddListener) activity;
   }

   public interface PlayerAddListener {
       public void onPlayerSave(Player p); // not shown in impl above
       public void onPlayerCancel();
   }

   public void btnCancel(View v) {
      callback.onPlayerCancel(); // the activity's implementation
   }
}