Android – is it safe to convert using getactivity()?

I am writing an application with a parent activity and several child fragments. I try to make the fragment communicate with the parent activity. I know there are several ways to do this, including creating an interface and implementing it in the parent activity. However, I am very interested in this method:

ParentActivity activity = (ParentActivity) getActivity();
activity.someMethod();

This method takes less code and less complexity. However, is it safe to do so in production code? Or is the interface more secure?

resolvent:

You can use this –

private ParentActivity callback;

@Override
public void onAttach(Activity activity)
{
    //callback = (ParentActivity ) activity;
    // make sure there is no cast exception
    callback = (ParentActivty.class.isAssignableFrom(activity
            .getClass())) ? (ParentActivity) activity : null;

    super.onAttach(activity);
}

@Override
public void onDetach()
{
    callback = null;
    super.onDetach();
}

Now when you make any method call, call it like this –

if(callback!=null)
{
callback.someMethod();
}

This method is very safe