How to handle “Up” button?

Question

How to handle \"Up\" button (SDK version 11+)? I am referring to the one at the top of screen, that holds the application icon.

In Android Design articles it was nam

Answer 1

Implement onOptionsItemSelected() and watch for android.R.id.home "menu" events, as is described in the documentation.

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
        case android.R.id.home:
            // do something useful
            return(true);
    }

    return(super.onOptionsItemSelected(item));
}

Answer 2

First change your AndroidManifest.xml file to have a parent activity declared. Eg

    <activity android:name=".theory"
              android:parentActivityName=".MainActivity"
        android:label="@string/theory"
        />
    <activity android:name=".experimental"
              android:parentActivityName=".MainActivity"
        android:label="@string/exp"
        />

Do this for all the activities other than the MainActivity. Note the parentActivityName xml code

Then go to the respective java files and add the following code

    ActionBar ab = getSupportActionBar();
    ab.setDisplayHomeAsUpEnabled(true);

You have you up button enabled now.