Assume there is a quite complicated open source Android Application. What I want to do is: to make a brand new Tabbed Activity inside the application and call/run an activity of the app in each tab. The called activity should run under the tab as if it was running on a normal window (or as if it was running on its own layout).
For instance; let the original project be a chat application with lots of services, permissions, activities, fragments etc one depending on another in a tangled fashion. In tab_1, I want to call the activity which lists the contacts. In tab_2, I want to call the activity which starts a conversation (brings chat screen - with a random person maybe - this is just an example). In tab_3 sent media is displayed. These activities all are included in the original project.
Now, it would be easy if I could turn the activities into fragments by doing;
class SomeProjectClass extends Fragment {...}
However SomeProjectClass already extends another class which is not Fragment. Is it possible to convert such an activity into a fragment? Or is there completely different way to embed the whole activity into a tab?
Maybe, instead of using a tabbed UI, I should simply add buttons to the action bar to navigate between the desired activities. But this would not have the aesthetics of the swipe move in tabbed screen.