release () 예외 후에 호출 된 메서드는 Android 카메라로 다시 시작할 수 없습니다.

release () 예외 후에 호출 된 메서드는 Android 카메라로 다시 시작할 수 없습니다.

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카메라 앱을 개발하는 동안 다른 앱 ( onPause()내 앱용)으로 전환 할 때만 발생하는 예외가 발생했습니다 .

01-15 17:22:15.017: E/AndroidRuntime(14336): FATAL EXCEPTION: main
01-15 17:22:15.017: E/AndroidRuntime(14336): java.lang.RuntimeException: Method called after release()
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.hardware.Camera.setPreviewDisplay(Native Method)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.hardware.Camera.setPreviewDisplay(Camera.java:357)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at com.sora.cbir.yuki.image.leaf.CameraPreview.surfaceCreated(CameraPreview.java:32)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.SurfaceView.updateWindow(SurfaceView.java:551)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.SurfaceView.onWindowVisibilityChanged(SurfaceView.java:213)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.View.dispatchWindowVisibilityChanged(View.java:4075)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.ViewGroup.dispatchWindowVisibilityChanged(ViewGroup.java:742)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.ViewRoot.performTraversals(ViewRoot.java:858)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.view.ViewRoot.handleMessage(ViewRoot.java:1995)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.os.Handler.dispatchMessage(Handler.java:99)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.os.Looper.loop(Looper.java:150)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at android.app.ActivityThread.main(ActivityThread.java:4389)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at java.lang.reflect.Method.invokeNative(Native Method)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at java.lang.reflect.Method.invoke(Method.java:507)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:849)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
01-15 17:22:15.017: E/AndroidRuntime(14336):    at dalvik.system.NativeStart.main(Native Method)

몇 가지 조사를했고 추가해야한다는 사실을 알게되었습니다.

mCamera.setPreviewCallback(null);

Android의 카메라 스택에 대한 해결 방법

내 onPause()지금은 다음과 같습니다.

@Override
protected void onPause() {
    super.onPause();
    try
    {    
        // release the camera immediately on pause event   
        //releaseCamera();
         mCamera.stopPreview(); 
         mCamera.setPreviewCallback(null);
         mCamera.release();
         mCamera = null;

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

그리고 내 onResume():

@Override
protected void onResume()
{
    super.onResume();
    try
    {
        mCamera.setPreviewCallback(null);
        mCamera = getCameraInstance();
        //mCamera.setPreviewCallback(null);
        mPreview = new CameraPreview(Imageupload.this, mCamera);//set preview
        preview.addView(mPreview);
    } catch (Exception e){
        Log.d(TAG, "Error starting camera preview: " + e.getMessage());
    }
}   
}

그리고 마지막으로 내 getCameraInstance()방법 :

public Camera getCameraInstance(){
    Camera camera = null;
    try {
        camera = Camera.open(); // attempt to get a Camera instance
    }
    catch (Exception e){
        // Camera is not available (in use or does not exist)
    }
    Camera.Parameters parameters = camera.getParameters();
    //mPreviewSize = getBestPreviewSize(parameters, wt, ht);
    //mPictureSize = getBestPictureSize(parameters, wt, ht);
    //Shift W & H => if camera rotates 90 deg

    mPreviewSize = getOptimalPreviewSize(parameters, wt, ht); //original => wt,ht
    mPictureSize = getOptimalPictureSize(parameters, wt, ht); //original => wt,ht

    Log.d("CAMERA", "SCREEN RESOLUTION H: "+ht);
    Log.d("CAMERA", "SCREEN RESOLUTION W: "+wt);

    Log.d("CAMERA", "PREVIEW RESOLUTION H: "+mPreviewSize.height);
    Log.d("CAMERA", "PREVIEW RESOLUTION W: "+mPreviewSize.width);

    Log.d("CAMERA", "PICTURE RESOLUTION H: "+mPictureSize.height);
    Log.d("CAMERA", "PICTURE RESOLUTION W: "+mPictureSize.width);
    //set preview size based on device screen
    parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
    //set picture size based on device screen
    parameters.setPictureSize(mPictureSize.width, mPictureSize.height);
    //set output camera mode
    parameters.setPictureFormat(PixelFormat.JPEG);
    //set focous mode
    parameters.setFocusMode(FOCUS_MODE_AUTO);
    //set flash mode
    parameters.setFlashMode("auto");
    List<int[]> fps = parameters.getSupportedPreviewFpsRange();
    //System.out.println("FPS size: " +fps.size());
    //System.out.println("MAX FPS:"+(fps.get(fps.size()-1)[1])/1000);
    //log min and max camera supported fps
    Log.d("CAMERA", "CAMERA MAX FPS: "+(fps.get(fps.size()-1)[1])/1000);
    Log.d("CAMERA", "CAMERA MIN FPS: "+(fps.get(fps.size()-1)[0])/1000);
    if(camera_fps)
    {
        parameters.setPreviewFpsRange(fps.get(fps.size()-1)[1], fps.get(fps.size()-1)[1]);
    }
    //set camera parameters
    camera.setParameters(parameters);

    Toast.makeText(getApplicationContext(), "Your device are capable of previewing @" + fps.get(fps.size()-1)[1]/1000+"fps!",Toast.LENGTH_SHORT).show();
    return camera; // returns null if camera is unavailable
}

이 문제를 해결하는 방법에 대한 아이디어가 있습니까?

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나도 같은 문제가 있습니다. mCamera.setPreviewCallback(null);도움이되지 않았습니다. 내 활동에서 나는 이것을 다음에 추가했습니다 releaseCamera.

mPreview.getHolder().removeCallback(mPreview);

이제 작동합니다.

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@ ookami.kb 솔루션이 저에게도 효과가 있었고 @srunni가 댓글을 달았습니다.

public void onPause() {
    super.onPause();

    if (mCamera != null) {
        mCamera.setPreviewCallback(null);
        mPreview.getHolder().removeCallback(mPreview);
        mCamera.release();
    }
}

나는 onDestroy 메소드도 제거했습니다.

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문서 camera.release()는 모든 카메라 리소스 를 해제 한다고 명확하게 말합니다 . 이 통화 후에는 더 이상 카메라 참조를 사용할 수 없습니다.

카메라를 다시 사용하려면 open(int)방법을 통해 획득해야합니다 .

카메라 문서 에 모두 설명되어 있습니다.

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올바르게 재개하려면 다음을 수행해야합니다.

@Override
public void onResume() {
    super.onResume();  

    // Get the Camera instance as the activity achieves full user focus
    if (mCamera == null) {
        initializeCamera(); // Local method to handle camera initialization
    }
}



protected void initializeCamera(){
    // Get an instance of Camera Object
    mCamera = getCameraInstance();

   // create a basic camera preview class that can be included in a View layout.
    mPreview=new CameraPreview(this,mCamera);

    //add your preview class to the FrameLayout element.
    preview.addView(mPreview);

   //Trigger capturing an image by calling the Camera.takePicture() method.
    captureButton.setOnClickListener(
            new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // get an image from the camera
                    mCamera.takePicture(null, null, mPicture);
                }
            }
        );
}

또한 oncreate ()에서 FrameLayout 미리보기 및 Button captureButton을 정의하는 것 외에는 아무것도하지 않습니다.

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@Override public void surfaceDestroyed(SurfaceHolder surfaceHolder) {

    this.getHolder().removeCallback(this);
    mCamera.stopPreview();
    mCamera.release();
    mCamera = null;
  Log.e("surfaceDestroyed", "surfaceDestroyed");

}

Resume 기능에서 카메라를 다시 초기화하십시오.

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okambi의 대답에 추가합니다.

재개 할 때 모든 것을 엉망으로 만드는 함수입니다.

 public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, now tell the camera where to draw the preview.
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            Log.d(TAG, "Error setting camera preview: " + e.getMessage());
        }
    }

try {}가 throw되는 예외를 포착하지 않습니다. 즉, mCamera가 존재하지 않고 setPreviewDisplay (holder)를 호출하려고하면 충돌이 발생합니다.

따라서 콜백을 제거하면이 surfaceCreated가 호출되지 않고 충돌을 방지합니다.

이것은 Google에서 문서화가 매우 부족합니다.

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나는 넣었다

mPreview.getHolder().removeCallback(mPreview);  

중에서.

mCamera.setPreviewCallback(null);

과

mCamera.release();

그리고 그것은 나를 위해 일했습니다.

 @Override
            protected void onPause() {
                super.onPause();

                this.saveTextEdits();
                try {
                    mCamera.stopPreview();
                    mCamera.setPreviewCallback(null);
                    **mPreview.getHolder().removeCallback(mPreview);**
                    mCamera.release();
                    mCamera = null;
                }catch (Exception e){

                }
            }

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I faced same issue, i fixed it by - Adding mCamera = null; in surfaceDestroyed(SurfaceHolder holder) method of Preview class.

public void surfaceDestroyed(SurfaceHolder holder) {
    // Surface will be destroyed when we return, so stop the preview.
    if (mCamera != null) {
        mCamera.stopPreview();
        mCamera.release();
        mCamera = null;
    }
}

and - Adding

camera = Camera.open();
    camera.startPreview();
    params = camera.getParameters();
    preview.setCamera(camera);

in OnResume() method of my CameraActivity.

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If you got:

Attempt to invoke virtual method 'void android.hardware.Camera.setPreviewCallback(android.hardware.Camera$PreviewCallback)' on a null object reference

I agree with @ookami.kb - mCamera.setPreviewCallback(null); is not enough, behind it also add this:

mCameraView.getHolder().removeCallback(mCameraView);

참고URL : https://stackoverflow.com/questions/8868732/method-called-after-release-exception-unable-to-resume-with-android-camera