OpenCV Android 环境搭建 及 实现测试案例（没有你想象的那么麻烦噢）

apply plugin: 'com.android.library'
android {
    compileSdkVersion 28
    buildToolsVersion "28.0.3"

    defaultConfig {
        minSdkVersion 14
        targetSdkVersion 28
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
        }
    }
}

dependencies {
}

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.lwp.myhhdaapplication"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation fileTree(dir: "$buildDir/native-libs", include: 'native-libs.jar')
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation project(':openCVLibrary330')
}

task nativeLibsToJar(type: Jar, description: 'create a jar archive of the native libs') {
    destinationDir file("$buildDir/native-libs")
    baseName 'native-libs'
    from fileTree(dir: 'libs', include: '**/*.so')
    into 'lib/'
}

tasks.withType(JavaCompile) {
    compileTask -> compileTask.dependsOn(nativeLibsToJar)
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/process_btn"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="灰度"/>

    <ImageView
        android:id="@+id/sample_img"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scaleType="fitCenter"
        android:src="@drawable/lena"
        android:layout_centerInParent="true"/>

</RelativeLayout>

package com.lwp.myhhdaapplication;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

import org.opencv.android.OpenCVLoader;
import org.opencv.android.Utils;
import org.opencv.core.Mat;
import org.opencv.imgproc.Imgproc;

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

    private String CV_TAG = "OpenCV";
    private Button processBtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        iniLoadOpenCV();//加载OpenCV的本地库
        processBtn = (Button) findViewById(R.id.process_btn);//实例化按钮并添加事件响应
        processBtn.setOnClickListener(this);
    }

    //加载OpenCV的本地库
    private void iniLoadOpenCV(){
        boolean success = OpenCVLoader.initDebug();
        if(success){
            Log.i(CV_TAG,"OpenCV Libraries loaded...");
        }else{
            Toast.makeText(this.getApplicationContext(), "WARNING: Could not load OpenCV Libraries!", Toast.LENGTH_LONG).show();
        }
    }

    //实现事件响应
    @Override
    public void onClick(View v) {
        Bitmap bitmap = BitmapFactory.decodeResource(this.getResources(), R.drawable.lena);
        Mat src = new Mat();
        Mat dst = new Mat();
        Utils.bitmapToMat(bitmap, src);
        Imgproc.cvtColor(src,dst,Imgproc.COLOR_BGRA2GRAY);
        Utils.matToBitmap(dst,bitmap);
        ImageView iv = (ImageView)this.findViewById(R.id.sample_img);
        iv.setImageBitmap(bitmap);
        src.release();
        dst.release();
    }
}