objective-c - UIImagePickerController 的快门

Question

我有 UIImagePickerController 的错误，源类型是相机。有时 Controller 出现后，快门打不开，看不到相机视频信号，但拍出来的照片是正确的。

可能是我做错了什么？代码:

    if ([UIImagePickerController isSourceTypeAvailable: UIImagePickerControllerSourceTypeCamera]){

            UIImagePickerController *cameraUI = [[UIImagePickerController alloc] init];
            cameraUI.sourceType = UIImagePickerControllerSourceTypeCamera;
            cameraUI.allowsEditing = NO;
            cameraUI.showsCameraControls = NO;
            cameraUI.delegate = self;

            NSArray *nibObjects = [[NSBundle mainBundle] loadNibNamed:@"OverlayView" owner:self options:nil];
            UIView *controlsView = [nibObjects objectAtIndex:0];

            CGRect overlayViewFrame = cameraUI.cameraOverlayView.frame;
            CGRect controlsFrame = CGRectMake(0.0, CGRectGetHeight(overlayViewFrame) - 54.0,
                                         CGRectGetWidth(overlayViewFrame), 54.0);

            controlsView.frame = controlsFrame;
            [cameraUI.cameraOverlayView addSubview:controlsView];

            [self presentModalViewController: cameraUI animated: YES];            
    }

Answer 1

在锁定/解锁应用程序后，同样的事情发生在我身上，看起来快门在 viewDidAppear 上打开了。

因此，我将我的父 View Controller 订阅到 UIApplicationDidBecomeActiveNotification 并手动重新执行包含 UIImagePickerController 的 Controller 的 viewWillAppear 和 viewDidAppear 方法

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(applicationBecomeActive)
                                             name:UIApplicationDidBecomeActiveNotification
                                           object:nil];

.
. 
.

- (void)applicationBecomeActive {
    if (imagePicker_)
        [imagePicker_ openShutter];
}

然后在包含 UIImagePickerController 的 Controller 上

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    [imagePickerController_ viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [imagePickerController_ viewDidAppear:animated];
    imagePickerController_.cameraFlashMode = cameraFlashMode_;
    imagePickerController_.cameraDevice = cameraDevice_;
}
- (void)openShutter {
    [imagePickerController_ viewWillAppear:YES];
    [imagePickerController_ viewDidAppear:YES];
}

PS:如果你尝试这个，不要忘记移除观察者

[[NSNotificationCenter defaultCenter] removeObserver:self];

希望对你有帮助