针对opencv导入Android studio不成功的解决办法？

一、问题如下：

   AS->File->New->Import Module 选择导入(压缩包路径)/sdk/java文件夹，然后发现AS没有下一步？

 二、解决办法

新建一个项目-在新建项目下创建一个包命名library

将opencv-android-sdk下的java包放进新建的包下改名opencv，写一个build文件(或者在github网站里找到自己想要的项目，将项目里面的library里面的文件复制到自己创建的library，这里，我是使用别人项目里面的包）

打开项目在setting.gradle添加include ':library

 添加依赖，File-Project Structure-Dependencies-点击app然后点击加号，选择3（module Dependency），选择library。

然后在main下创建jniLib包，将opencv-sdk-native-libs下的文件复制到jniLib文件下。

 以上是基本完成了opencv环境的配置。

三、下面介绍两个基于opencv的两个小demo。

  1、图片灰度化

import androidx.appcompat.app.AppCompatActivity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;

import org.opencv.android.Utils;
import org.opencv.core.Mat;
import org.opencv.imgproc.Imgproc;
import org.opencv.osgi.OpenCVNativeLoader;

public class MainActivity extends AppCompatActivity {
    private ImageView mImageView;

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

        OpenCVNativeLoader loader = new OpenCVNativeLoader();
        loader.init();

        mImageView = findViewById(R.id.imageView);
        mImageView.setImageResource(R.drawable.img_origin);
        mImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Bitmap bitmap = BitmapFactory.decodeResource(MainActivity.this.getResources(),R.drawable.img_origin);
                Mat mat = new Mat();
                Mat grayMat = new Mat();
                Utils.bitmapToMat(bitmap,mat);
                Imgproc.cvtColor(mat, grayMat, Imgproc.COLOR_RGB2GRAY);
                Utils.matToBitmap(grayMat,bitmap);
                mImageView.setImageBitmap(bitmap);
            }
        });
    }
}

XML的程序如下

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent" />


</androidx.constraintlayout.widget.ConstraintLayout>

 2、人脸检测

mainActivity下的程序如下：

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;

import android.Manifest;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;

import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.OpenCVLoader;
import org.opencv.android.Utils;
import org.opencv.core.Core;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.core.Size;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;
import org.opencv.osgi.OpenCVNativeLoader;

import java.io.File;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.util.logging.Logger;

public class MainActivity extends AppCompatActivity implements CameraBridgeViewBase.CvCameraViewListener2 {
    private CameraBridgeViewBase openCvCameraView;

    private static final String TAG = "OpencvActivity";
    private CascadeClassifier cascadeClassifier = null; //级联分类器
    private Mat mRgba; //图像容器
    private Mat mGray;
    private int absoluteFaceSize = 0;
    private Handler handler;

    private void initializeOpenCVDependencies() {
        try {
            InputStream is = getResources().openRawResource(R.raw.lbpcascade_frontalface_improved); //OpenCV的人脸模型文件： lbpcascade_frontalface_improved
            File cascadeDir = getDir("cascade", Context.MODE_PRIVATE);
            File mCascadeFile = new File(cascadeDir, "lbpcascade_frontalface_improved.xml");
            FileOutputStream os = new FileOutputStream(mCascadeFile);
            byte[] buffer = new byte[4096];//其实byte[] buffer = new byte[4096]只是在内存中开辟块缓冲区而已。大小随便你写（假如你不是Extreme Programming的FANS），只要不超过你实际可用内存大小就好。不过太大或者太小都会对性能有影响
            int bytesRead;
            while ((bytesRead = is.read(buffer)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            is.close();
            os.close();
            // 加载cascadeClassifier
            cascadeClassifier = new CascadeClassifier(mCascadeFile.getAbsolutePath());
        } catch (Exception e) {
            Log.e(TAG, "Error loading cascade", e);
        }
        // 显示
        openCvCameraView.enableView();
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if(requestCode == 0) {
            try {
                for(int i = 0; i < permissions.length; i++) {
                    Log.d(TAG, permissions[i] + ":" + grantResults[i]);
                }

            }catch(Exception e){
                e.printStackTrace();
            }
        }

    }



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

       //new GetRunAuthorityUtil().getRunAuthority(this, this); //动态获取权限

        ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.CAMERA,
                Manifest.permission.WRITE_EXTERNAL_STORAGE},1);

        handler = new Handler();

        openCvCameraView = (CameraBridgeViewBase) findViewById(R.id.javaCameraView);
        openCvCameraView.setCameraIndex(1); //摄像头索引        -1/0：后置双摄     1：前置
        openCvCameraView.enableFpsMeter(); //显示FPS
        openCvCameraView.setCvCameraViewListener(this);
    }

    @Override
    public void onResume() {
        super.onResume();
        if (!OpenCVLoader.initDebug()) {
            Log.e(TAG, "OpenCV init error");
        }
        initializeOpenCVDependencies();
    }

    @Override
    public void onCameraViewStarted(int width, int height) {
        mRgba = new Mat();
        mGray = new Mat();
    }

    @Override
    public void onCameraViewStopped() {
        mRgba.release();
        mGray.release();
    }

    @Override
    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
        mRgba = inputFrame.rgba(); //RGBA
        mGray = inputFrame.gray(); //单通道灰度图

        if (absoluteFaceSize == 0) {
            int height = mGray.rows();
            if (Math.round(height * 0.2f) > 0) {
                absoluteFaceSize = Math.round(height * 0.2f);
            }
        }

        //解决  前置摄像头旋转显示问题
        //Core.flip(mRgba, mRgba, 1); //旋转
        //Core.flip(mGray, mGray, 1);

        //检测并显示
        MatOfRect faces = new MatOfRect();
        if (cascadeClassifier != null) {
            cascadeClassifier.detectMultiScale(mGray, faces, 1.1, 2, 2, new Size(absoluteFaceSize, absoluteFaceSize), new Size());
        }
        Rect[] facesArray = faces.toArray();
        if (facesArray.length > 0){
            for (int i = 0; i < facesArray.length; i++) {    //用框标记
                Imgproc.rectangle(mRgba, facesArray[i].tl(), facesArray[i].br(), new Scalar(0, 255, 0, 255), 3);
            }
        }
        return mRgba;
    }

}

XML下的程序如下

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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">

    <org.opencv.android.JavaCameraView
        android:id="@+id/javaCameraView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>


</androidx.constraintlayout.widget.ConstraintLayout>

  在res下创建一个raw包，将opencv-android-sdk下面的sdk-etc-libpacascades里面的两个文件复制到raw里面,如下图：

然后运行，应该没啥问题。