Weird error message:
Gradle: A problem occurred configuring project ':App'. > Failed to notify project evaluation listener. > Could not resolve all dependencies for configuration ':App:_DefaultFlavorDebugCompile'. > Could not find any version that matches com.android.support:appcompat-v7:+. Required by: MyApplication:App:unspecified
If this happens, just go to Tools -> Android -> Android SDK Manager, then check “Android Support Repository” and “Android Support Library” under “Extra” and install them. That should take care of the error.