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

我也遇到了同样的问题,我通过检查相机是否可用来解决它:

BOOL cameraAvailableFlag = [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera];
    if (cameraAvailableFlag)
        [self performSelector:@selector(showcamera) withObject:nil afterDelay:0.3];

其他回答

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。

我已经尝试了一切,我的问题是,相机和图片库的图像选择器在它们显示后立即消失。我用下面这行(swift)解决了它

imagePicker.modalPresentationStyle = UIModalPresentationStyle.OverCurrentContext

或者,考虑使用drawviewherarchyinrect:

迅速:

extension UIImage{

    class func renderUIViewToImage(viewToBeRendered: UIView) -> UIImage
    {
        UIGraphicsBeginImageContextWithOptions(viewToBeRendered.bounds.size, true, 0.0)
        viewToBeRendered.drawViewHierarchyInRect(viewToBeRendered.bounds, afterScreenUpdates: true)
        viewToBeRendered.layer.renderInContext(UIGraphicsGetCurrentContext()!)

        let finalImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        return finalImage
    }
}

objective - c:

- (UIImage *)snapshot:(UIView *)view
{
    UIGraphicsBeginImageContextWithOptions(view.bounds.size, YES, 0);
    [view drawViewHierarchyInRect:view.bounds afterScreenUpdates:YES];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return image;
}

还看到:

https://developer.apple.com/library/ios/qa/qa1817/_index.html 如何捕获UIView到UIImage而不损失视网膜显示的质量

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。

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!