Question

I have a title bar in my application. And the title bar has one button. On click of that button I display info activity. Now, as far as I know, android:onClick needs a reference of a public method inside the activity which has the xml set in setContentView(). Now, as the logic for that buttons click will be the same throughout the application, so what I want is, I will the method just once say showInfoScreen(View view) and put it in that buttons onClick attribute. And I need not write the same method everywhere. Is it possible?

Answer 1

Of course it’s possible. Write an Activity class, then have all of your Activitys extend it. For example:

public abstract class BaseActivity extends Activity {

    @Override
    public void setContentView( int layoutResID ) {

        super.setContentView( layoutResID );
        findViewById(R.id.button).setOnClickListener(new OnTitleBarButtonClickListener());
    }

    private void showInfoScreen() {

        // Show the info screen
    }

    private class OnTitleBarButtonClickListener implements OnClickListener {

        @Override
        public void onClick(View v) {

            showInfoScreen();
        }
    }
}

Then all of your derived Activitys would extend BaseActivity instead of Activity.

The beauty of doing it this way is that any Activity that extends this class automatically gets this feature. No coding is required in the derived classes, just in BaseActivity. The only contract all of your Activitys will have will be to have R.id.button or whatever id you name it within its content.