Question

I’m working on an android application that currently has two Activities, A and B, that have some code in common, their options menu and some other code. To cut down on copying and pasting, I created a class called BaseActivity that extends Activity with the, and I then had A and B extend BaseActivity. At least that’s what I wanted to do, but I ran into a problem. While A now extends BaseActivity just fine, I can’t figure out how to make B extend BaseActivity because it’s not just an activity, it’s a MapActivity. So it’s inheritance tree looks like this:

MapActivity inheritance tree:

java.lang.Object
   android.content.Context
       android.content.ContextWrapper
           android.view.ContextThemeWrapper
               android.app.Activity
                   com.google.android.maps.MapActivity

But in order for it to inherit my code, I’d need to make it look like this:

java.lang.Object
   android.content.Context
       android.content.ContextWrapper
           android.view.ContextThemeWrapper
               android.app.Activity
                  mypackage.BaseActivity
                     com.google.android.maps.MapActivity

Is there any way to insert my custom class in an inheritance tree?

Answer 1

No, you can’t. It’s hard to say exactly what the best approach would be here, but I would at least try to use composition instead of inheritance. Can you implement a separate non-activity object and use one of those from both A and B?