Creating abstract Activity classes

Question

I am working on creating abstract activity classes for my application that I will reuse for each activity.

1. Super Class: android.app.Activity

2. My Abstract Class extends android.app.Activity myActivity

3. Example activty in my application extends myActivity.

I will have 10-20 of these exampleActivity.

How can I write my abstract class (#2) to force my example class to override methods in android.app.Activity like onCreate() and onStart()?

Is this possible in Java?

Solution 1

Not really.

However you can create abstract functions myOnCreate and myOnStart and call those in your abstract class implementation of onCreate and onStart.

You might also want to make onCreate/onStart final, although it's difficult to see what the benefit is of forcing myOnCreate instead of onCreate.

Solution 2

This is possible,

public abstract class MyActivity extends android.app.Activity
{

    public abstract void onCreat(...);
    public abstract void onStart(...);
}

public class OtherActivity extends MyActivity
{
    public void onCreate(...)
    {
        //write your code
    }

    public void onStart(...)
    {
      //write your code
    }
}

Comments

[Squonk]

@user721378: I'd be interested to know how that works out with an Android Activity.

[J.S. Taylor]

Sorry it's an activity class. Please forget about that i said about constructors or setters. You can pass interface class names through intent, but it makes everything much more complex. Why don't you just create an abstract method with a different name?

[Laurence Gonsalves]

While the technique presented here is a good one, I'm a bit baffled by the "Not really" in this answer. You can make onCreate, etc. abstract in an abstract subclass of Activity. Perhaps it's a bad idea (particularly with methods like onBackPressed that have non-empty default implementations that you might want to call via super) but it can certainly be done.