退出后CWAC-camera异常“释放后调用的方法（）”

Question

首先，我是英语的废话。

我正在开发一个使用Android相机的项目。

我的团队正在使用CWAC相机，我的项目也是如此。

到目前为止，我认为它真的很棒。我正在显示相机的预览。 问题是，当我尝试关闭应用程序时（使用物理“返回”按钮），它会崩溃。并非总是如此。

事实上，当我在CameraPreviewFragment中的src.release（）之前关闭时，它似乎崩溃了。 但是，如果我在src.release（）之后关闭应用程序，它似乎运行良好。 这不是100％肯定，我说这要归功于记录器。

这是错误：

  

5529-5529 / net.personal.opencv_tester W / dalvikvm：threadid = 1：线程退出时未捕获异常（组= 0x41a222a0）

     

06-10 10：04：50.960 30241-30241 / net.personal.opencv_tester E / MINE DEBUG：开始

     

06-10 10：04：51.015 30241-30241 / net.personal.opencv_tester E / MINE DEBUG：发布之前

     

06-10 10：04：51.015 30241-30241 / net.personal.opencv_tester E / MINE DEBUG：刚发布后

     

06-10 10：04：51.015 30241-30241 / net.personal.opencv_tester E / MINE DEBUG：结束

     

06-10 10：04：51.555 30241-30241 / net.personal.opencv_tester E / AndroidRuntime：

     

致命的例外：主要

> java.lang.RuntimeException: Method called after release()
        at android.hardware.Camera.setHasPreviewCallback(Native Method)
        at android.hardware.Camera.access$600(Camera.java:139)
        at android.hardware.Camera$EventHandler.handleMessage(Camera.java:867)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:176)
        at android.app.ActivityThread.main(ActivityThread.java:5419)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1046)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:862)
        at dalvik.system.NativeStart.main(Native Method)

这就是它的工作原理：

  

06-10 10：06：56.480 32508-32508 / net.personal.opencv_tester E / MINE DEBUG：开始

     

06-10 10：06：56.495 32508-32508 / net.personal.opencv_tester E / MINE DEBUG：发布之前

     

06-10 10:06：56.495 32508-32508 / net.personal.opencv_tester E / MINE DEBUG：发布后

     

06-10 10：06：56.495 32508-32508 / net.personal.opencv_tester E / MINE DEBUG：结束

     

06-10 10：06：57.225 32508-32508 / net.personal.opencv_tester E / MINE DEBUG：On detach

这是我的代码：

MainActivity.java

package net.personal.opencv_tester;

import org.opencv.android.OpenCVLoader;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Window;
import android.view.WindowManager;
import com.commonsware.cwac.camera.CameraHost;
import com.commonsware.cwac.camera.CameraHostProvider;
import com.commonsware.cwac.camera.SimpleCameraHost;

public class MainActivity
    extends Activity
    implements CameraHostProvider
{

private static final String TAG = MainActivity.class.getSimpleName();

@Override
protected void onCreate( Bundle savedInstanceState )
{
    super.onCreate( savedInstanceState );

    requestWindowFeature( Window.FEATURE_NO_TITLE );
    getWindow().setFlags( WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN );

    setContentView( R.layout.activity_main );
}

static {
    if (!OpenCVLoader.initDebug()) {
        // Handle initialization error
    }
}

@Override
public CameraHost getCameraHost()
{
    SimpleCameraHost.Builder builder =
            new SimpleCameraHost.Builder( new CustomCameraHost( this ) );
    builder.useFullBleedPreview( true );
    return builder.build();
}
}

CustomCameraHost.java

package net.personal.opencv_tester;

import java.io.File;
import android.content.Context;
import com.commonsware.cwac.camera.SimpleCameraHost;

public class CustomCameraHost
    extends SimpleCameraHost
{

private final File outFile;

public CustomCameraHost( File outFile, Context context )
{
    super( context );
    this.outFile = outFile;
}

public CustomCameraHost( Context context )
{
    super( context );
    this.outFile = new File(context.getFilesDir(), "test.jpg");
}

@Override
public boolean useSingleShotMode()
{
    return true;
}

@Override
protected File getPhotoPath()
{
    return outFile;
}

@Override
protected boolean scanSavedImage()
{
    return false;
}
}

最后，错误发生在哪里：

CameraPreviewFragment.java

package net.personal.opencv_tester;

import org.opencv.core.Core;
[...] 
import com.commonsware.cwac.camera.CameraFragment;
import com.commonsware.cwac.camera.CameraView;
import com.jjoe64.graphview.BarGraphView;
import com.jjoe64.graphview.GraphView;


public class CameraPreviewFragment
    extends CameraFragment
    implements Camera.PreviewCallback, SensorEventListener, OnClickListener
{

private CameraView mCameraView;
private TextView mTextView;
private GraphView mGraphView;
private TextView mInfosTextView;

private long mLastCheck = System.currentTimeMillis();

@Override
public void onAttach( Activity activity )
{
    Log.e("MINE DEBUG", "On attach");
    super.onAttach( activity );
}

@Override
public void onDetach()
{
    Log.e("MINE DEBUG", "On detach");
    super.onDetach();
}

@Override
public View onCreateView( LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState )
{
    View view = LayoutInflater.from( getActivity() ).inflate( R.layout.fragment_preview, container, false );
    view.setOnClickListener( this );

    mTextView = ( TextView ) view.findViewById( R.id.cameraWarningTextView );

    mCameraView = ( CameraView ) view.findViewById( R.id.cameraSurfaceView );
    mCameraView.setHost( getHost() );

    //Camera.open(getHost().getCameraId()).setOneShotPreviewCallback(this);
    mCameraView.setPreviewCallback( this );
    setCameraView( mCameraView );

    FrameLayout graphLayout = ( FrameLayout ) view.findViewById( R.id.cameraHistLayout );
    mGraphView = new BarGraphView( getActivity(), "Histogram" );
    mGraphView.getGraphViewStyle().setTextSize( 17f );
    mGraphView.getGraphViewStyle().setHorizontalLabelsColor( 0xffffffff );
    mGraphView.getGraphViewStyle().setVerticalLabelsColor( 0xffffffff );
    mGraphView.setVisibility( View.GONE );
    graphLayout.addView( mGraphView );

    mInfosTextView = ( TextView ) view.findViewById( R.id.cameraInfosTextView );
    mInfosTextView.setVisibility( View.GONE );

    return view;
}

@Override
public void onClick( View v )
{
    autoFocus();
}

@Override
public void onSensorChanged( SensorEvent event )
{   
}

@Override
public void onAccuracyChanged( Sensor sensor, int accuracy )
{
}

@Override
public void onPreviewFrame( byte[] data, Camera camera )
{
    Log.e("MINE DEBUG", "Begining");
    long now = System.currentTimeMillis();

    // Check an image every 500ms
    if (mLastCheck + 500 > now) {
        return;
    }
    mLastCheck = now;

    int frameHeight = camera.getParameters().getPreviewSize().height;
    int frameWidth = camera.getParameters().getPreviewSize().width;

    // Create default grayscale matrix

    Mat src = new Mat( frameHeight, frameWidth, CvType.CV_8UC1 );
    src.put( 0, 0, data );

    // Resize if image is too large (for performances)
    if (src.width() > 640) {
        double ratio = ( double ) src.width() / ( double ) src.height();
        Imgproc.resize( src, src, new Size( 640, 640 / ratio ), 0, 0, Imgproc.INTER_LINEAR );
    }

    // Remove noise
    Imgproc.GaussianBlur( src, src, new Size( 3, 3 ), 0.5 );

    try {
        mTextView.setText( "Valid image" );
        mTextView.setCompoundDrawablesWithIntrinsicBounds(getResources().getDrawable(R.drawable.ic_capture_ok), null,
                null, null);
    } finally {
        Log.e("CHECK DEBUG", "Just Before Release");
        src.release();
        Log.e("CHECK DEBUG", "Just After Release");
    }
    Log.e("MINE DEBUG", "End");
}
}

我浏览了StackOverflow并找到了“修复”，但它无法正常工作

 mCameraView.setPreviewCallback(null);

非常感谢你的耐心等待。我找不到修复方法。