Android: cannot use Admob due to String types not allowed at 'configChanges'

I was trying to use Admob in my app and added this to my AndroidManifest.xml:


<activity

android:name="com.google.ads.AdActivity"    android:configChanges="keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize" >

</activity>

then there is a build error:

Sting types not allowed at 'configChanges' with value 'keyboard|keyboardHidden|orientation|screenLayout|uiMode|screenSize|smallestScreenSize'.

Turns out to use Admob you need to change build target to be at least 13. You can still let your app run on lower Android versions even your build target is 13. build target is only for build. Your minimum required OS version is specified by uses-sdk minSdkVersion.

http://stackoverflow.com/questions/7902121/admob-cant-display-ads-because-of-configchanges