Android导入OpenCV配置使用

1.下载OpenCV-android-sdk

官网下载sdk，打开opencv官网，点击Android，完成后解压
https://opencv.org/

解压后，文件夹下有这些文件

• samples Android代码工程
• sdk 包含opencv的Java的接口和JNI接口等
  

2.新建工程

打开Android studio，选择模板，这时选择最后一项Native c++，然后进入配置界面。

• 这里注意你下载的Android-sdk版本来选择api

• 选择C++14，finish

3.环境配置

1. 将OpenCV库作为Module导入。具体步骤为：File->New->Import Module，然后将OpenCV-android-sdk\sdk目录导入，最好顺便将模块名改成opencv+版本号。如下图，然后Next->Finish。
   
2. 修改OpenCV下的gradle文件, apply plugin: 'com.android.library,并将API改为与app一致
   
3. 添加依赖，菜单栏选择File->Project Structure，在Dependencies选项中选择app，点击+，选择Module dependency，如下图：
   
   勾选OpenCV，点击OK，等待同步
   
4. 新建jinLibs文件夹， 右键main，选择New-Folder-JNI Folder，如下图，并改名为jniLibs
   

• 打开解压缩后的opencv-android-sdk文件，将sdk\native\jni\include文件夹下的opencv2文件夹复制到cpp下将sdk\native\libs下的文件夹复制到jniLibs下，如下图
  
  
  

5. 配置参数，打开app的gradle，添加sourceSets

sourceSets {        main{            jni.srcDirs = ['src/main/jniLibs']        }    }

在externalNativeBuild下添加以下代码

externalNativeBuild {            cmake {                cppFlags '-std=c++14 -frtti -fexceptions'                abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86', 'x86_64'                arguments '-DANDROID_STL=c++_shared'            }        }

这时环境就算配置好了，接下来用一个简单的灰度化来验证一下

灰度化

java代码

package com.example.myandroidopencv;import androidx.annotation.NonNull;import androidx.annotation.Nullable;import androidx.appcompat.app.AppCompatActivity;import android.content.ContentResolver;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.util.Log;import android.view.View;import android.widget.Button;import android.widget.ImageView;import android.widget.TextView;import com.example.myandroidopencv.databinding.ActivityMainBinding;import org.opencv.android.OpenCVLoader;import org.opencv.android.Utils;import org.opencv.core.CvType;import org.opencv.core.Mat;import org.opencv.imgproc.Imgproc;import java.io.File;import java.io.FileNotFoundException;public class MainActivity extends AppCompatActivity implements View.OnClickListener {    private ImageView img;    private Button btn_load, btn_gray;    private Bitmap bitmap;    // Used to load the 'myandroidopencv' library on application startup.    static {        System.loadLibrary("myandroidopencv");    }    private ActivityMainBinding binding;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        binding = ActivityMainBinding.inflate(getLayoutInflater());        setContentView(binding.getRoot());        img = findViewById(R.id.img);        btn_load = findViewById(R.id.btn_load);        btn_gray = findViewById(R.id.btn_gray);        btn_load.setOnClickListener(this);        btn_gray.setOnClickListener(this);    }        public native String stringFromJNI();    @Override    public void onClick(View view) {        switch (view.getId()){            case R.id.btn_load:                loadImg();                break;            case R.id.btn_gray:                doChgGray();                break;        }    }    private void loadImg(){        Intent intent = new Intent();        intent.setType("image/*");        intent.setAction(Intent.ACTION_GET_CONTENT);        startActivityForResult(intent,1);    }    private void doChgGray(){        if (bitmap==null){            return;        }        Bitmap bit = bitmap.copy(Bitmap.Config.ARGB_8888,false);        Mat src = new Mat(bit.getHeight(), bit.getWidth(), CvType.CV_8UC(3));        Utils.bitmapToMat(bit,src);        Imgproc.cvtColor(src,src,Imgproc.COLOR_BGR2GRAY);        Utils.matToBitmap(src,bitmap);        Message message = new Message();        message.what = 1;        handler.sendMessage(message);    }    @Override    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {        //用户操作完成，结果返回码是-1        if (resultCode==RESULT_OK){            Uri uri = data.getData();            Log.e("uri",uri.toString());            ContentResolver cr = this.getContentResolver();            try {                bitmap = BitmapFactory.decodeStream(cr.openInputStream(uri));                img.setImageBitmap(bitmap);            }catch(FileNotFoundException ex){                Log.e("Exception",ex.getMessage(),ex);            }        }else{            //操作错误，或没有选择图片            Log.i("MainActivity", "操作错误");        }        super.onActivityResult(requestCode, resultCode, data);    }    @Override    protected void onResume() {        super.onResume();        if (!OpenCVLoader.initDebug()){            Log.i("cv","未找到内部的opencv库，使用OpenCV Manager进行初始化");        }else {            Log.i("cv","发现了内置的opencv库，使用它来进行操作");        }    }    Handler handler = new Handler(){        @Override        public void handleMessage(@NonNull Message msg) {            super.handleMessage(msg);            switch (msg.what){                case 1:                    img.setImageBitmap(bitmap);                    break;            }        }    };}

页面布局代码

来源地址：https://blog.csdn.net/weixin_45178274/article/details/129491697