Question

I’m trying to add the action bar programatically as shown in the dev documentaion but I’m coming across an error. My minSdk is set to 11, my application has one layout and one activity and the only code in the activity is:

@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    setContentView(R.layout.inbox);
    ActionBar actionBar = getActionBar();
    actionBar.show();

}

If I take out those last two lines then my app runs. I know that the holo theme include the actionbar automatically, but I don’t like the editTextviews. Any ideas on why this is happening. Should I be using the HoloTheme and themeing the views differently?

Again, I’m not getting any errors in eclipse. My program is crashing from what I can decipher from logcat as an null pointer exception.

Answer 1

From the documentation you linked to:

If you have a custom activity theme in which you’d like to remove the action bar, set the android:windowActionBar style property to false. However, if you remove the action bar using a theme, then the window will not allow the action bar at all, so you cannot add it later—calling getActionBar() will return null.

Since you’re using a theme without an action bar, getACtionBar() is returning null, and then you’re attempting to call show() on that null, resulting in an Exception being thrown.

So that explains the error you’re getting. As far as what to do about it, the documentation for ActionBar says:

Beginning with Android 3.0 (API level 11), the action bar appears at the top of an activity’s window when the activity uses the system’s Holo theme (or one of its descendant themes), which is the default. You may otherwise add the action bar by calling requestFeature(FEATURE_ACTION_BAR) or by declaring it in a custom theme with the windowActionBar property.

That gives you two easy options to have an ActionBar without using a Holo theme. This is probably simplest in your case:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    getWindow().requestFeature(Window.FEATURE_ACTION_BAR); // Add this line
    setContentView(R.layout.inbox);
    ActionBar actionBar = getActionBar();
    actionBar.show();
}

Update: You should also switch to just Theme.Black without the NoTitleBar part, as that prevents the ActionBar from working.