Your Activity (Moovo) inherits the application theme specified in your AndroidManifest. Your theme is a parent of Theme.AppCompat.Light.DarkActionBar. This theme removes the native android.app.ActionBar which is why getActionBar() returns null.
You should do one of two things:
First option:
Have your Activity class Moovo extend AppCompatActivity and use getSupportActionBar() instead of getActionBar().
Your changes would look something like this:
java
...
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
...
public class Moovo extends AppCompatActivity {
...
@Override
public void onCreate(Bundle savedInstanceState) {
...
ActionBar actionBar = getSupportActionBar();
...Second Option:
Do not use an AppCompat based theme. All AppCompat themes remove the native ActionBar and replace it with android.support.v7.app.ActionBar for backwards compatibility.