当屏幕关闭时，后台相机预览出错

Question

代码基于 GoogleSamples，并在示例代码中更改了一些内容以便在后台预览而不是拍照。

例如：

     @Override
    public void onResume() {
        super.onResume();
        /*startBackgroundThread();

        // When the screen is turned off and turned back on, the SurfaceTexture is already
        // available, and "onSurfaceTextureAvailable" will not be called. In that case, we can open
        // a camera and start preview from here (otherwise, we wait until the surface is ready in
        // the SurfaceTextureListener).
        if (mTextureView.isAvailable()) {
            openCamera(mTextureView.getWidth(), mTextureView.getHeight());
        } else {
            mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
        }*/
    }

    @Override
    public void onPause() {
        /*closeCamera();
        stopBackgroundThread();*/
        super.onPause();
    }

   public synchronized void start() {
        if (mCameraDevice != null) {
            return;
        }
        startBackgroundThread();

        // When the screen is turned off and turned back on, the SurfaceTexture is already
        // available, and "onSurfaceTextureAvailable" will not be called. In that case, we can open
        // a camera and start preview from here (otherwise, we wait until the surface is ready in
        // the SurfaceTextureListener).
        if (mTextureView.isAvailable()) {
            openCamera(mTextureView.getWidth(), mTextureView.getHeight());
        } else {
            mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
        }
    }

    public synchronized void stop() {
        if (mCameraDevice == null) {
            return;
        }
        closeCamera();
        stopBackgroundThread();
    }

但是，当屏幕关闭一分钟时，相机预览出现错误： enter image description here enter image description here

为什么以及如何避免？

Answer 1

startForegroundService(new Intent(this, EmptyService.class));

activity 需要前台服务，然后一切正常。

当屏幕关闭时，后台相机预览出错

When screen is off, camera preview in background comes to error

android

android-camera2