android studio 上配置opencv4Android

The below steps for using Android OpenCV sdk in Android Studio. Thanks to TGMCains answer which is simplified below.

Download latest OpenCV sdk for Android from OpenCV.org and
decompress the zip file.
Import OpenCV to Android Studio, From File -> Import Module, choose sdk/java folder
in the unzipped opencv archive.
Update build.gradle under imported OpenCV module to update 4 fields to match your project build.gradle a) compileSdkVersion
b) buildToolsVersion c) minSdkVersion and 4) targetSdkVersion.
Add module dependency by Application -> Module Settings, and select
the Dependencies tab. Click + icon at bottom, choose Module Dependency and select the
imported OpenCV module.
Copy libs folder under sdk/native to
Android Studio under app/src/main.
In Android Studio, rename the copied libs directory to jniLibs and
we are done.

Step (6) is since Android studio expects native libs in

app/src/main/jniLibs

instead
of older

libs

folder.
For those new to Android OpenCV, don't miss below steps

include

static{
System.loadLibrary("opencv_java"); }

For step(5), if you ignore any platform libs like x86, make sure your device/emulator is not on that platform.

OpenCV written is in C/C++. Java wrappers are

Android
OpenCV SDK - OpenCV.org maintained Android Java wrapper. I suggest this one.
OpenCV
Java - OpenCV.org maintained auto generated desktop Java wrapper.
JavaCV -
Popular Java wrapper maintained by independent developer(s). Not Android specific. This library might get out of sync with OpenCV newer versions.