在安卓系统中连接到相机服务失败

Question

从另一个活动导航到相机活动时，得到一个异常 "未能连接到相机服务".问题发生在Camera.open().我搜索了很多，也尝试了可用的解决方案，但问题没有解决，请提供一些帮助，先谢谢了。

 @Override
    public void surfaceChanged(final SurfaceHolder holder, int arg1,
            int arg2, int arg3) {


        cameraHandler = new Handler() {
            /*
             * (non-Javadoc)
             * 
             * @see android.os.Handler#handleMessage(android.os.Message)
             */
            @Override
            public void handleMessage(Message msg) {
                switch (msg.what) {
                case LOADCAMERA:
                    if (null != mProgress) {
                        if (mProgress.isShowing()) {
                            mProgress.dismiss();
                        }
                    }
                    try {
                        try {

                            mCam = Camera.open(); // attempt to get a Camera
                                                    // instance
                        } catch (Exception e) {
                            Log.e("Exception", e.getMessage());
                        }
                        mCam.setPreviewDisplay(holder);
                        mCameraParameters = mCam.getParameters();
                        if (isFlashLightOn) {
                            mCameraParameters
                                    .setFlashMode(Parameters.FLASH_MODE_TORCH);
                        } else {
                            mCameraParameters
                                    .setFlashMode(Parameters.FLASH_MODE_OFF);
                        }
                        mCameraParameters.setPreviewSize(mVideoWidth,
                                mVideoHeight);
                        mCam.setParameters(mCameraParameters);
                        mCam.startPreview();
                        mCam.unlock();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                }
                super.handleMessage(msg);
            }
        };
        Message msg = new Message();
        msg.what = LOADCAMERA;
        cameraHandler.sendMessageDelayed(msg, 700);

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder arg0) {


        if (mCam != null) {
            mCam.stopPreview();
            mCam.setPreviewCallback(null);
            mCam.release();
            mCam = null;
        }

    }
}

日志猫已添加

W/CameraService(   78): CameraService::connect X (pid 623) rejected (camera 0 is still      busy).
E/Exception(  623): Fail to connect to camera service
D/AndroidRuntime(  623): Shutting down VM
W/dalvikvm(  623): threadid=1: thread exiting with uncaught exception(group=0x40015560)
E/AndroidRuntime(  623): FATAL EXCEPTION: main
E/AndroidRuntime(  623): java.lang.NullPointerException
E/AndroidRuntime(  623):    at   com.gui.MainActivity$CameraPreview$1.handleMessage(MainActivity.java:2041)
E/AndroidRuntime(  623):    at android.os.Handler.dispatchMessage(Handler.java:99)
E/AndroidRuntime(  623):    at android.os.Looper.loop(Looper.java:130)
E/AndroidRuntime(  623):    at  android.app.ActivityThread.main(ActivityThread.java:3683)
E/AndroidRuntime(  623):    at java.lang.reflect.Method.invokeNative(Native Method)
E/AndroidRuntime(  623):    at java.lang.reflect.Method.invoke(Method.java:507)
E/AndroidRuntime(  623):    at    com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:845)
E/AndroidRuntime(  623):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:603)
E/AndroidRuntime(  623):    at dalvik.system.NativeStart.main(Native Method)
W/ActivityManager(  106):   Force finishing activity com.gui/.MainActivity
W/ActivityManager(  106):   Force finishing activity com.gui/.MainActivity
E/v4l2_utils(   78): Error = Try again from dqbuf
E/SEC_Overlay(   78): Failed to DQ/-1
E/CameraHardwareSec(   78): ERR(int    android::CameraHardwareSec::previewThread()):overlay dequeueBuffer fail
I/CameraHardwareSec(   78): int android::CameraHardwareSec::previewThreadWrapper():  calling mSecCamera->stopPreview() and waiting
I/CameraHardwareSec(   78): int android::CameraHardwareSec::previewThreadWrapper(): return from wait
I/CameraHardwareSec(   78): int android::CameraHardwareSec::previewThreadWrapper(): exiting
W/SecCamera(   78): int android::SecCamera::stopPreview(): doing nothing because m_flag_camera_start is zero
I/CameraHardwareSec(   78): virtual void android::CameraHardwareSec::release(): calling mPreviewHeap.dispose()
W/SecCamera(   78): int android::SecCamera::stopRecord(): doing nothing because     m_flag_record_start is zero
I/SecCamera(   78): DeinitCamera: m_cam_fd(15)
I/SecCamera(   78): DeinitCamera: m_cam_fd2(21)

Answer 1

CameraService::connect X (pid 623) rejected (camera 0 is still busy).

这意味着其他进程(App)已经调用了'Camera.open'并且没有释放它。在它释放之前，你无法访问相机。

你说的 "当从另一个活动导航到相机活动时，得到一个异常 "未能连接到相机服务 "是什么意思？

这个其他活动是什么，它是否访问了摄像机？

Answer 2

也许，您可以在您的MainActivity中添加。

protected override void OnDestroyed() {
    if (mCam != null) {
        mCam.release();
    }
}

我想你的错误可能是因为摄像头在退出之前仍然与应用程序保持着开放的连接。至少，这就是解决我问题的方法。