快速移动设备时不触发AVCaptureDeviceSubjectAreaDidChangeNotification

Question

当我的用户点击聚焦时，我注册了AVCaptureDeviceSubjectAreaDidChangeNotification的通知，这是我的代码：

        CGPoint autofocusPoint = CGPointMake(xValue, yValue);
        [device setFocusPointOfInterest:autofocusPoint];
        [device setFocusMode:AVCaptureFocusModeAutoFocus];

        CGPoint exposurePoint = CGPointMake(xValue, yValue);
        [device setExposurePointOfInterest:exposurePoint];
        [device setExposureMode:AVCaptureExposureModeAutoExpose];

        RCTLogWarn(@"DID autofocusand autoexpose");

        if (!self.isFocusedOnPoint) {
            self.isFocusedOnPoint = true;

            RCTLogWarn(@"clog: ok add listener");
            device.subjectAreaChangeMonitoringEnabled = YES;
            [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(AutofocusDelegate:) name:AVCaptureDeviceSubjectAreaDidChangeNotification object:device];
        }

      }

但是，如果我快速移动设备，快速更改相机视图的主题，则不会触发通知。我必须移动设备，直到最终看到此触发器。有人遇到这个问题吗？

在我的通知代表中，我撤消了点击以专注于以下目的：

AVCaptureDevice *device = [self.videoCaptureDeviceInput device];

if (self.isFocusedOnPoint) {
    RCTLogWarn(@"clog: ok remove listener");

    self.isFocusedOnPoint = false;

    CGPoint autofocusPoint = CGPointMake(0.5f, 0.5f);
    CGPoint exposurePoint = CGPointMake(0.5f, 0.5f);

    [device setExposurePointOfInterest: autofocusPoint];
    [device setFocusPointOfInterest: exposurePoint];

    [device setFocusMode:AVCaptureFocusModeContinuousAutoFocus];
    [device setExposureMode:AVCaptureExposureModeContinuousAutoExposure];

    [[NSNotificationCenter defaultCenter] removeObserver:self name:AVCaptureDeviceSubjectAreaDidChangeNotification object:device];
    device.subjectAreaChangeMonitoringEnabled = NO;
}