在iOS 8中,我有从相机捕捉图像的问题,直到现在我正在使用这段代码

UIImagePickerController *controller=[[UIImagePickerController alloc] init];
controller.videoQuality=UIImagePickerControllerQualityTypeMedium;
controller.delegate=(id)self;
controller.sourceType=UIImagePickerControllerSourceTypeCamera;
[self presentViewController:controller animated:YES completion:nil];

但在iOS 8中,我得到了这个:

Snapshotting a view that has not been rendered results in an empty snapshot. Ensure your view has been rendered at least once before snapshotting or snapshot after screen updates.

我已经尝试了本文提供的解决方案

@property (strong,nonatomic)UIImagePickerController *controller;

_controller=[[UIImagePickerController alloc] init];
_controller.videoQuality=UIImagePickerControllerQualityTypeMedium;
_controller.delegate=(id)self;
_controller.sourceType=UIImagePickerControllerSourceTypeCamera;
_[self presentViewController:controller animated:YES completion:nil];

...
controller.modalPresentationStyle=UIModalPresentationFullScreen;
or
controller.modalPresentationStyle=UIModalPresentationCurrentContext;
...

double delayInSeconds = 0.1;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
    [self presentViewController:controller animated:YES completion:nil];
});

[self presentViewController:controller animated:YES completion:NULL];

[self presentViewController:controller animated:YES completion:^{

}];

任何想法?


当前回答

在我的情况下(XCode 7和iOS 9),我使用UINavigationController“隐藏”,所以我必须添加UINavigationControllerDelegate来呈现相机或滚动,它的工作就像它应该做的!和pickerControllerDelegate。Self也不显示错误!

其他回答

我很确定这只是iOS 8.0的一个bug。这是最简单的POC应用程序的可复制性,它只是尝试呈现一个UIImagePickerController,就像你上面做的那样。此外,据我所知,没有其他模式可以显示图像拾取器/相机。你甚至可以下载苹果的Using UIImagePickerController示例应用程序,运行它,它会立即生成相同的错误。

也就是说,功能对我来说仍然有效。除了警告/错误,你的应用程序的功能有问题吗?

我使用Phonegap,但这个线程一直作为第一个当谷歌关于错误消息。

对我来说,通过将imagetype定义为PNG,这个问题就消失了。

encodingType : Camera.EncodingType.PNG

所以整条线是:

 navigator.camera.getPicture(successFunction, failFunction, { encodingType : Camera.EncodingType.PNG, correctOrientation:true, sourceType : Camera.PictureSourceType    .PHOTOLIBRARY, quality: 70, allowEdit : false , destinationType: Camera.DestinationType.DATA_URL});

你的里程可能会有所不同,但这对我来说很管用。

I don't have enough reputation points to comment on @greg's answer above, so will add my observations here. I have a Swift project for both iPad and iPhone. I have a method inside my main view controller (relevant bit below). When I test this on a phone, everything works properly and no warnings are generated. When I run it on an iPad, everything works properly but I see the warning about snapshotting the view. The interesting bit, however, is that when I run on an iPad without using the popover controller, everything works properly with no warning. Unfortunately, Apple mandates that the image picker must be used within a popover on iPad, if the camera is not being used.

    dispatch_async(dispatch_get_main_queue(), {
        let imagePicker: UIImagePickerController = UIImagePickerController();
        imagePicker.sourceType = UIImagePickerControllerSourceType.SavedPhotosAlbum;
        imagePicker.mediaTypes = [kUTTypeImage];
        imagePicker.allowsEditing = false;
        imagePicker.delegate = self;

        if(UIDevice.currentDevice().userInterfaceIdiom == .Pad){ // on a tablet, the image picker is supposed to be in a popover
            let popRect: CGRect = buttonRect;
            let popover: UIPopoverController = UIPopoverController(contentViewController: imagePicker);
            popover.presentPopoverFromRect(popRect, inView: self.view, permittedArrowDirections: UIPopoverArrowDirection.Up, animated: true);
        }else{
            self.presentViewController(imagePicker, animated: true, completion: nil);
        }
    });

对于任何人来说,在图像捕捉后看到黑色预览的问题,隐藏状态栏后显示UIPickerController似乎可以解决这个问题。

UIImagePickerControllerSourceType source = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] ? UIImagePickerControllerSourceTypeCamera : UIImagePickerControllerSourceTypeSavedPhotosAlbum;
UIImagePickerController *cameraController = [[UIImagePickerController alloc] init];
        cameraController.delegate = self;
        cameraController.sourceType = source;
        cameraController.allowsEditing = YES;
        [self presentViewController:cameraController animated:YES completion:^{
            //iOS 8 bug.  the status bar will sometimes not be hidden after the camera is displayed, which causes the preview after an image is captured to be black
            if (source == UIImagePickerControllerSourceTypeCamera) {
                [[UIApplication sharedApplication] setStatusBarHidden:YES withAnimation:UIStatusBarAnimationNone];
            }
        }];

我发现了同样的问题,并尝试了所有方法。我有两个不同的应用程序,一个在objective-C和一个在swift -两者都有同样的问题。错误消息出现在调试器中,屏幕在第一张照片之后变黑。这只发生在iOS >= 8.0,显然这是一个错误。

我找到了一个困难的变通办法。用imagePicker关闭相机控制。showsCameraControls = false并创建自己的overlayView,其中有缺失的按钮。关于如何做到这一点,有各种各样的教程。 奇怪的错误信息保留了下来,但至少屏幕不会变黑,而且你有一个工作的应用程序。