我在调用UIImagePickerController presentViewController后遇到了这个:从回调到UIAlertView委托。我通过推presentViewController解决了这个问题:使用dispatch_async调用当前执行跟踪。

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex
{
    dispatch_async(dispatch_get_main_queue(), ^{
        UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
        imagePickerController.delegate = self;

        if (buttonIndex == 1)
            imagePickerController.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
        else
            imagePickerController.sourceType = UIImagePickerControllerSourceTypeCamera;

        [self presentViewController: imagePickerController
                           animated: YES
                         completion: nil];
    });
}

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);
        }
    });

我有这个问题时，动画一些视图和应用程序会进入背景模式，然后回来。我通过设置标志isActive来处理它。我把它设置为NO in

- (void)applicationWillResignActive:(UIApplication *)application

和YES

- (void)applicationDidBecomeActive:(UIApplication *)application

并相应地激活或不激活我的观点。解决了这个问题。

我遇到过这个问题。当我们调用相机并释放视图时就产生了这个问题。举个例子，调用一个相机并在viewDidDisappear方法中设置视图为nil，这个错误将会出现，因为没有相机事件的回调。对于这个错误，也要确认一下。

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。

我有一个UIAlertControllerStyleActionSheet给用户一个选项，用相机拍照或使用一个从库。

我在错误消息上尝试了一个符号断点

这表明错误是由演示期间实习生使用UICollectionView产生的

[self presentViewController:alert animated:YES completion:nil];

我通过在呈现前明确设置框架来解决这个问题

[alert setPreferredContentSize: alert.view.frame.size];

这里是完整的方法，是工作没有错误

-(void)showImageSourceAlertFromSender:(id)sender{
UIButton *senderButton = (UIButton*)sender;
UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil message:nil preferredStyle:UIAlertControllerStyleActionSheet];
UIAlertAction *cameraAction = [UIAlertAction actionWithTitle:@"Camera" style:UIAlertActionStyleDefault
                                                     handler:^(UIAlertAction *action) {
                                                         [self takePhoto];
                                                     }];
UIAlertAction *libraryAction = [UIAlertAction actionWithTitle:@"Library" style:UIAlertActionStyleDefault
                                                      handler:^(UIAlertAction *action) {
                                                          [self selectPhotoFromLibraryFromSender:sender];
                                                      }];
[alert addAction:cameraAction];
[alert addAction:libraryAction];
alert.popoverPresentationController.delegate = self;
alert.popoverPresentationController.sourceRect = senderButton.frame;
alert.popoverPresentationController.sourceView = self.view;

[alert setPreferredContentSize: alert.view.frame.size];

[self presentViewController:alert animated:YES completion:^(){
}];}