Android ActionBar NullPointerException
You Actionbar returns null because you don't have actionbar but you are requesting using getActionbar()
Make sure that you've window feature to show your actionbar, That is required for the actionbar to show. Check the below links for more details. ...check this question getActionBar returns null And also check this link for the more information on your problem http://blog.perpetumdesign.com/2011/08/strange-case-of-dr-action-and-mr-bar.html
You Remove
android:theme="@style/AppTheme"
in "application" from AndroidManifest.xml