在android studio中使用OpenCV进行人脸检测。E/AndroidRuntime：致命异常：main

Question

我正在用OpenCV做人脸检测的应用程序。应用程序安装在手机里，但是由于致命的错误，它突然关闭了。这是我的主要活动。java

package com.example.oc2;

import androidx.appcompat.app.AppCompatActivity;

import android.content.Context;
import android.os.Bundle;
import org.opencv.android.BaseLoaderCallback;
import org.opencv.android.CameraActivity;
import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewFrame;
import org.opencv.android.LoaderCallbackInterface;
import org.opencv.android.OpenCVLoader;
import org.opencv.core.Mat;
import org.opencv.android.CameraBridgeViewBase.CvCameraViewListener2;

import org.opencv.android.CameraBridgeViewBase;
import org.opencv.android.JavaCameraView;
import org.opencv.core.Mat;
import org.opencv.core.MatOfRect;
import org.opencv.core.Point;
import org.opencv.core.Rect;
import org.opencv.core.Scalar;
import org.opencv.imgproc.Imgproc;
import org.opencv.objdetect.CascadeClassifier;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

public class MainActivity extends AppCompatActivity implements CameraBridgeViewBase.CvCameraViewListener2{
    JavaCameraView javaCameraView;
    File cascfile;
    CascadeClassifier facedetector;
    private Mat mRgba,mGrey;



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

        if(!OpenCVLoader.initDebug())
        {
            OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_3_4_0,this, baseCallback);
        }
            else
        {
            try {
                baseCallback.onManagerConnected(LoaderCallbackInterface.SUCCESS);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
            javaCameraView.setCvCameraViewListener(this);
    }

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

    }

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

    }

    @Override
    public Mat onCameraFrame(CameraBridgeViewBase.CvCameraViewFrame inputFrame) {
        mRgba=inputFrame.rgba();
        mGrey=inputFrame.gray();
        MatOfRect facedetection= new MatOfRect();
        facedetector.detectMultiScale(mRgba,facedetection);
        for(Rect rect: facedetection.toArray())
        {
            Imgproc.rectangle(mRgba,new Point(rect.x,rect.y),new Point(rect.x+rect.width,rect.y+rect.height),new Scalar(255,0,0));
        }
        return mRgba;
    }

    private final BaseLoaderCallback baseCallback=new BaseLoaderCallback(this) {
        @Override
        public void onManagerConnected(int status) throws IOException {
            switch (status)
            {
                case LoaderCallbackInterface.SUCCESS:
                {
                    InputStream is = getResources().openRawResource(R.raw.haarcascade_frontalface_alt2);
                    File cascadedir=getDir( "cascade" , Context.MODE_PRIVATE);
                    cascfile= new File(cascadedir, "haarcascade_frontalface_alt2.xml" );
                    FileOutputStream fos= new FileOutputStream(cascfile);

                    byte[] buffer=new byte[4096];
                    int bytesread;
                    while((bytesread = is.read(buffer))!=-1)
                    {
                        fos.write(buffer,0,bytesread);
                    }
                    is.close();
                    fos.close();
                    facedetector=new CascadeClassifier(cascfile.getAbsolutePath());
                    if(facedetector.empty())
                    {
                        facedetector=null;
                    }
                    else
                    {
                        cascadedir.delete();
                    }
                    javaCameraView.enableView();

                }
                break;

                default:
                    {
                    super.onManagerConnected(status);
                    }
                    break;

            }

        }
    };
}

这是我的错误，有人能帮忙吗？

如果有人能给出解决错误的步骤，这将是非常有帮助的。

Answer 1

再见,

我对你的代码有两种感觉：

1-在oncreate活动中，缺少一行：

javaCameraView = (CameraBridgeViewBase) findViewById(R.id.java_camera_view);

因此，对此片段进行测试，但要想使其正常工作，您需要在启动应用程序[设置->apps->yourapp->permissions->camera]之前启用应用程序的camera权限。权限部分必须重写正确，这只是为了快速测试

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

    javaCameraView = (CameraBridgeViewBase) findViewById(R.id.java_camera_view);

    // added for black screen
    if (ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)
            == PackageManager.PERMISSION_GRANTED) {
        Log.d(TAG, "Permissions granted");
        javaCameraView.setCameraPermissionGranted();    
        javaCameraView.setCameraIndex(CameraBridgeViewBase.CAMERA_ID_FRONT);    
        javaCameraView.setVisibility(CameraBridgeViewBase.VISIBLE);
        javaCameraView.setCvCameraViewListener(this);
    } else {
        Log.d(TAG, "Troubles");
    }   
}