Chris will try the following after updating ur AS to 2.4 ...
ProjectStructure-> Project-> Change Android Plugin version to version 2.2.0.
: build.gradle( NOT build build.gradle) :
classpath 'com.android.tools.build:gradle:2.2.0'
Sdk build.gradle:
android{
System.out.printf("ndkDirectory: %s \n", ndkDirectory);
}
, !