在单独的线程中关闭CameraDevice [英] Close CameraDevice in a seperate thread

问题描述

我正在使用Android camera2创建自定义相机. cameraDevice.close()方法很慢，它会使UI冻结1秒钟.我把它放在另一个线程中，它似乎工作得很好.我想知道这是否会引起一些严重的问题，以及是否还有另一种方法可以解决此问题.这是我的closeCamera方法:

I am using Android camera2 to create a custom camera. The cameraDevice.close() method is slow and it makes UI freeze for 1 sec. I put it in another thread and it seems to work just fine. I want to know if this will cause some serious problem and whether there is another way to achieve this. Here is my closeCamera method:

private void closeCamera() {
    boolean release = false;
    try {
        mCameraOpenCloseLock.acquire();
        release = true;
    } catch (InterruptedException e) {
        release = false;
    }
    try {
        preparing = true;
        if (mCaptureSession != null) {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && mCaptureSession.isReprocessable()
                    || validCameraSession) {
                mCaptureSession.close();
            }
            mCaptureSession = null;
            validCameraSession = false;
        }
    } catch (IllegalStateException e) {
        mCaptureSession = null;
    } catch (Exception e) {
        mCaptureSession = null;
    }
    try {
        new Thread(new Runnable() {
            @Override
            public void run() {
                if (mCameraDevice != null) {
                    if (openCamera) {
                        mCameraDevice.close();
                        mCameraDevice = null;
                    }
                }
            }
        }).start();

    } catch (IllegalStateException e) {
        Log.e(TAG, "closeCamera: mCaptureSession - ", e);
    } catch (Exception e) {
        Log.e(TAG, "closeCamera: mCaptureSession - ", e);
    }

    if (release) {
        if (mCameraOpenCloseLock != null) {
            int lock = mCameraOpenCloseLock.availablePermits();
            if (lock > 1) mCameraOpenCloseLock.release(lock - 1);
            else if (lock == 0) mCameraOpenCloseLock.release();
        }
    }
}

我认为当mCameraDevice尚未关闭但用户再次打开相机时，可能会导致崩溃.但这是极少数情况，我想在再次打开相机之前再进行一次检查.我不希望UI冻结1秒以使其关闭，除了将其放在单独的线程中之外，还有其他方法可以实现吗?

I think it may cause crash when mCameraDevice has not been closed but user open camera again. But it is rare case, and I am thinking of putting another check before open camera again. I don't want my UI to freeze 1 sec for it to close, is there any other way I can achieve that except putting it in seperate thread?

推荐答案

据我所知，cameraDevice.close()的这种冻结发生在某些不幸的设备上，有时可以通过执行常规系统升级来解决.

As far as I know, such freeze with cameraDevice.close() happens on some unfortunate devices, and sometimes is cured by performing a normal system upgrade.

但是，如果这发生在您的设备上，这有点安慰.实际上，您很幸运可以为此准备一个修复程序.您的应用程序的最终用户将从您的不幸中受益.

But this is a little consolation if this happens to you, on your device. Actually, you are kind of lucky that you can prepare a fix for that. The end-users of your app will benefit from your misfortune.

如果您的代码可以为您提供所需的改进，则您的代码看起来不错.正如我所解释的，可能很难在另一个设备上重现此问题.

Your code looks OK, if it delivers desired improvements for you. As I explained, it may be hard to reproduce this problem on another device.

我宁愿将所有closeCamera()逻辑放在同一后台线程上.如果您为 openCamera()提供了 Handler ，则为

I would rather put all closeCamera() logic on the same background thread. If you provided a Handler to openCamera(), as in the official example,

manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);

然后我建议将所有closeCamera()序列发布到此 mBackgroundHandler .

then I would suggest posting all closeCamera() sequence to this mBackgroundHandler.

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