Check that the following SDKs are installed and up-to-date.
Tools->SDK Manager:
OpenCV is a required module dependency which you must install yourself.
Download the latest android library version from the OpenCV website and extract the zip.
In Android Studio, go to File->New->Import Module and select the
extracted directory/src (which contains the build.gradle file). Then rename the module to
opencv. Android Studio should build the project successfully.