Android Studio - Action Bar remove

I had this issue too. I went to styles.xml and changed

parent="Theme.AppCompat.Light.DarkActionBar" 

to

parent="Theme.AppCompat.Light.NoActionBar"

and that removed it from all my activities.

in your oncreate() method use this

getActionBar().hide();

If your minSdkVersion is 10 or lower, instead use:

getSupportActionBar().hide();