How to extend an activity from the MainActivity class file?

Question

The UI elements in the MainActivity class need to be preserved and the other class file adds a new UI element to the main xml layout that's used by both classes to differing degrees.

It's understood that you can create a base abstract class and two concrete inherited classes however in this case there a third supporting class for the second (other class) and it requires a handler to function.

For perspective, a button (in activity_main ) is clicked and it should launch an activity while maintaining the UI elements used MainActivity . Furthermore the button has it's own class file methods and isn't in MainActivity .

What happens now? The button is pressed and nothing happens. Manifest confirmed so its not that. Or I allow the main activity or the other activity and it works, both need to work simultaneously.

Basically MainActivity needs to act as the base abstract activity for the separate class file.

Answer 1

You are messing up activities and views. To reuse the same business logic, you can write common logic in base class for all other activities (ie class BaseActivity extends Activity ). To reuse different UI parts you should either use fragments or you can use <include>/<merge> tags pair to include a certain layout into another layout.