(Android Studio) Error! : You need to use a Theme.AppCompat theme (or descendant) with this activity.

You need to use a Theme.AppCompat theme (or descendant) with this activity.

이런 오류가 나오면??

AppCompatActivity를 Activity로 바꿈

출처 : 

http://yenos.tistory.com/entry/tip%ED%85%8C%EB%A7%88%EA%B4%80%EB%A0%A8-error-you-need-to-use-a-themeappcompat-theme-or-descendant-with-this-activity