UIImagePickerController没有在iOS 8中呈现

Question

是否有其他人UIImagePickerController在iOS 8中遇到问题？下面的方法在iPad上的iOS 7中运行得非常好,但是当我尝试呈现选择器(最后一行)时,我在XCode 6(Beta 3或4)中运行时会出现以下错误.如果重要,那么sourceType的选择来自于在同一个地方呈现的alertView.

Warning: Attempt to present <UIImagePickerController: 0x7c0ae400>  on <CAGUCreateContactViewController: 0x7bf61a00> which is already presenting (null)

打开imagePicker的方法.

- (void)openPhotoPicker:(UIImagePickerControllerSourceType)sourceType
{
    if ([UIImagePickerController isSourceTypeAvailable:sourceType]) {
        NSArray *availableMediaTypes = [UIImagePickerController availableMediaTypesForSourceType:sourceType];
        if ([availableMediaTypes containsObject:(NSString *)kUTTypeImage]) {
            UIImagePickerController *imagePickerController = [[UIImagePickerController alloc] init];
            imagePickerController.modalPresentationStyle = UIModalPresentationFullScreen;
            imagePickerController.sourceType = sourceType;
            imagePickerController.mediaTypes = @[(NSString *)kUTTypeImage];
            imagePickerController.delegate = self;

            self.imagePickerController = imagePickerController;

            if (sourceType == UIImagePickerControllerSourceTypeCamera) {
                [self presentViewController:self.imagePickerController animated:YES completion:nil];
            } else {                    
                if (self.popoverVC) {
                    [self.popoverVC dismissPopoverAnimated:YES];
                    self.popoverVC = nil;
                }

                self.popoverVC = [[UIPopoverController alloc] initWithContentViewController:imagePickerController];
                [self.popoverVC presentPopoverFromRect:self.nameAndPicCell.picture.frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionUp animated:YES];
            }
        }
    }
}

Answer 1

我认为这是因为在iOS 8中,警报视图和操作表实际上是视图控制器(UIAlertController).因此,如果您正在呈现一个新的视图控制器以响应来自该动作的动作UIAlertView,那么它将在UIAlertController被解雇时呈现.我通过延迟UIImagePickerController直到下一次runloop迭代的演示来解决这个问题,通过这样做:

[[NSOperationQueue mainQueue] addOperationWithBlock:^{
    [self openPhotoPicker:sourceType];
}];

但是,解决这个问题的正确方法是UIAlertController在iOS 8上使用新的API(即使用if ([UIAlertController class])...来测试它).如果您尚未使用新API,这只是一种解决方法.

Answer 2

我同意Ben Lings问题的检测.在使用UIActionSheet时,我会建议一个更简单的解决方案.我只是简单地移动了我的代码,该代码对Action Sheet选择起反应:

- (void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex;
{
// my code
}

成:

- (void)actionSheet:(UIActionSheet *)actionSheet didDismissWithButtonIndex:(NSInteger)buttonIndex;  // after animation
{
// my code
}

这样,应用程序可以保证在UIActionSheet动画完成后将执行代码.

由于UIAlertView具有类似的委托方法:

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex;  // after animation
{
// my code
}

我想类似的解决方案可能适用.

Answer 3

这是一个适合我的解决方案

if([[[UIDevice currentDevice] systemVersion] floatValue]>=8.0)
{
    [[NSOperationQueue mainQueue] addOperationWithBlock:^{

        [self presentViewController:cameraUI animated:NO completion:nil];
    }];

}
else{

    [controller presentViewController:cameraUI animated:NO completion:nil];
}

记住分配 cameraUI

UIImagePickerController *cameraUI = [[UIImagePickerController alloc] init];
cameraUI.sourceType = UIImagePickerControllerSourceTypeCamera;

建立和去!

Answer 4

我在iOS 8中遇到了同样的问题.然后我在设备上看到了iOS即8.0.2的最新更新的更改日志.

本次更新中提到_

"修复了导致某些应用无法访问照片库中的照片的问题"

因此,在iOS 8.0.2版本的设备上使用XCode 6测试您的应用程序它将正常工作不要在iOS 8.0模拟器上测试它.

这对我有所帮助,希望对你也一样.