android.hardware.camera2.CameraAccessException: CAMERA_DISCONNECTED (2): cancelRequest:473: 相机设备不再活动

如何解决android.hardware.camera2.CameraAccessException: CAMERA_DISCONNECTED (2): cancelRequest:473: 相机设备不再活动

运行我的应用，我可以看到完美的相机视图，现在我打开内置相机应用并再次切换到我自己的应用程序（在这里，我只有黑屏）

日志

2020-12-26 16:57:45.696 16445-16768/app.video I/CameraManagerGlobal: Camera 0 facing CAMERA_FACING_BACK state now CAMERA_STATE_IDLE for client app.video API Level 2
2020-12-26 16:57:45.883 16445-16768/app.video I/CameraManagerGlobal: Camera 0 facing CAMERA_FACING_BACK state now CAMERA_STATE_CLOSED for client app.video API Level 2
2020-12-26 16:57:45.886 16445-16596/app.video E/CameraCaptureSession: Session 0: Exception while stopping repeating: 
    android.hardware.camera2.CameraAccessException: CAMERA_DISCONNECTED (2): cancelRequest:473: Camera device no longer alive
        at android.hardware.camera2.CameraManager.throwAsPublicException(CameraManager.java:1127)
        at android.hardware.camera2.impl.ICameraDeviceUserWrapper.cancelRequest(ICameraDeviceUserWrapper.java:97)
        at android.hardware.camera2.impl.CameraDeviceImpl.stopRepeating(CameraDeviceImpl.java:1151)
        at android.hardware.camera2.impl.CameraCaptureSessionImpl.close(CameraCaptureSessionImpl.java:526)
        at android.hardware.camera2.impl.CameraCaptureSessionImpl$2.onDisconnected(CameraCaptureSessionImpl.java:737)
        at android.hardware.camera2.impl.CameraDeviceImpl$7.run(CameraDeviceImpl.java:244)
        at android.os.Handler.handleCallback(Handler.java:883)
        at android.os.Handler.dispatchMessage(Handler.java:100)
        at android.os.Looper.loop(Looper.java:237)
        at android.os.HandlerThread.run(HandlerThread.java:67)
     Caused by: android.os.ServiceSpecificException: cancelRequest:473: Camera device no longer alive (code 4)
        at android.os.Parcel.createException(Parcel.java:2102)
        at android.os.Parcel.readException(Parcel.java:2056)
        at android.os.Parcel.readException(Parcel.java:2004)
        at android.hardware.camera2.ICameraDeviceUser$Stub$Proxy.cancelRequest(ICameraDeviceUser.java:676)
        at android.hardware.camera2.impl.ICameraDeviceUserWrapper.cancelRequest(ICameraDeviceUserWrapper.java:95)
        at android.hardware.camera2.impl.CameraDeviceImpl.stopRepeating(CameraDeviceImpl.java:1151) 
        at android.hardware.camera2.impl.CameraCaptureSessionImpl.close(CameraCaptureSessionImpl.java:526) 
        at android.hardware.camera2.impl.CameraCaptureSessionImpl$2.onDisconnected(CameraCaptureSessionImpl.java:737) 
        at android.hardware.camera2.impl.CameraDeviceImpl$7.run(CameraDeviceImpl.java:244) 
        at android.os.Handler.handleCallback(Handler.java:883) 
        at android.os.Handler.dispatchMessage(Handler.java:100) 
        at android.os.Looper.loop(Looper.java:237) 
        at android.os.HandlerThread.run(HandlerThread.java:67) 
2020-12-26 16:57:45.886 16445-16596/app.video I/org.webrtc.Logging: Camera2Session: Stop internal
2020-12-26 16:57:45.887 16445-16596/app.video I/org.webrtc.Logging: SurfaceTextureHelper: stopListening()
2020-12-26 16:57:45.887 16445-16468/app.video W/app.video: Long monitor contention with owner CaptureThread (16596) at boolean android.os.BinderProxy.transactNative(int,android.os.Parcel,int)(BinderProxy.java:-2) waiters=0 in void android.hardware.camera2.impl.CameraDeviceImpl$CameraDeviceCallbacks.onCaptureStarted(android.hardware.camera2.impl.CaptureResultExtras,long) for 381ms
2020-12-26 16:57:45.890 16445-16596/app.video I/org.webrtc.Logging: Camera2Session: Stop done
2020-12-26 16:57:45.890 16445-16596/app.video I/org.webrtc.Logging: CameraCapturer: Stop capture
2020-12-26 16:57:45.890 16445-16596/app.video I/org.webrtc.Logging: CameraCapturer: Stop capture: Nulling session
2020-12-26 16:57:45.891 16445-16596/app.video I/org.webrtc.Logging: CameraCapturer: Stop capture done
2020-12-26 16:57:45.891 16445-16596/app.video I/org.webrtc.Logging: Camera2Session: Camera device closed.
2020-12-26 16:57:45.892 16445-16596/app.video I/org.webrtc.Logging: Camera2Session: Stop camera2 session on camera 0
2020-12-26 16:57:45.892 16445-16768/app.video I/CameraManagerGlobal: Camera 1 facing CAMERA_FACING_FRONT state now CAMERA_STATE_OPEN for client com.sec.android.app.camera API Level 1
2020-12-26 16:57:46.274 16445-16839/app.video I/CameraManagerGlobal: Camera 1 facing CAMERA_FACING_FRONT state now CAMERA_STATE_ACTIVE for client com.sec.android.app.camera API Level 1

XML

<com.src.webrtc.android.VideoView
     android:id="@+id/main_view"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content" />

代码

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)

    viewModel = ViewModelProvider(
        this,ViewModelFactory.getInstance(application)
    ).get(MainViewModel::class.java)

    binding = DataBindingUtil.setContentView(this,R.layout.activity_main)
    binding.viewModel = this.viewModel
    binding.lifecycleOwner = this

    binding.apply {
        peerViews.add(mainView)
        peerViews.add(subView1)
        for (i in viewRenderers.indices) {
            viewRenderers[i].setTarget(peerViews[i])
        }
    }

    viewModel.room.observe(this,Observer {
        Log.d(TAG,"observe room $it")
        if (it != null) {
            binding.mainView.apply {
                init(null)
                setScalingType(RendererCommon.ScalingType.SCALE_ASPECT_FIT)
                setEnableHardwareScaler(false)
            }
            initSubView(it,binding.subView1)
        } else {
            binding.mainView.clearImage()
            binding.subView1.clearImage()
            Handler().postDelayed({
                binding.mainView.release()
                binding.subView1.release()
            },100)
        }
    })

}

解决方法

当您将应用置于后台，然后从该应用中分离相机时，您可以在 onPause() 方法中执行此操作，然后在再次打开应用时在 onResume() 方法中重新附加它。

,

在您的相机中执行此操作@Override protected void onResume() { super.onResume(); try { if (AppConstants.isActivityPaused) {//isActivityPaused is boolean var in AppConstant class startCamera(); mBinding.frmCameraPreview.startPreview(); AppConstants.isActivityPaused = false; } } catch (Exception e) { e.printStackTrace(); } } @Override protected void onPause() { AppConstants.isActivityPaused = true; try { if (mCamera != null) {//mCamera is Camera object mCamera.stopPreview(); mCamera.lock(); mCamera.release(); mCamera = null; } } catch (Exception e) { e.printStackTrace(); } super.onPause(); } private void startCamera() { mBinding.frmCameraPreview.requestLayout(); try { if (mCamera == null) mCamera = getCameraInstance(); if (mCamera != null) { //setup camera } } catch (Exception e) { e.printStackTrace(); } } /** * Helper method to access the camera returns null if it cannot get the * camera or does not exist * * @return camera */ private Camera getCameraInstance() { Camera camera = null; try { camera = Camera.open(); if (camera == null) { camera = getFrontFacingCamera(); } } catch (Exception e) { e.printStackTrace(); } return camera; } /** * if there is no back camera we will get front camera instance * * @return front camera */ private Camera getFrontFacingCamera() { int cameraCount; Camera cam = null; Camera.CameraInfo cameraInfo = new Camera.CameraInfo(); cameraCount = Camera.getNumberOfCameras(); for (int camIdx = 0; camIdx < cameraCount; camIdx++) { Camera.getCameraInfo(camIdx,cameraInfo); if (cameraInfo.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) { cam = Camera.open(camIdx); } } if (cam == null) cam = Camera.open(); return cam; }

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