Question

I have an activity and a fragment. The fragment has a button on it.

I load the fragment:

fragment = new FragmentPIN(this);                   
fragmentTransaction.add(R.id.content,fragment);         
fragmentTransaction.commit();

then try to set the listener

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {

        Button cmdOK_PIN = (Button)activity.findViewById(R.id.cmdOK_PIN);
        cmdOK_PIN.setOnClickListener(new View.OnClickListener() {                       
            @Override
            public void onClick(View v) {

            }

        });

    } catch (ClassCastException e) {
        e.printStackTrace();
    }
}

But I always get a null pointer exception on the setOnClickListener call. The fragment transaction is committed before I attempt to set the listener. Or I think it is. Should I be using another override to do this?

Answer 1

Try changing where you set the listener to the onActivityCreated instead of onAttach. According to the Android docs:

onActivityCreated is called when the fragment’s activity has been created and this fragment’s view hierarchy instantiated.

When you call onAttach that’s before the Activity has setup its view