iOS 11 UIImagePickerController 后选择取消按钮错误答案

【问题标题】：iOS 11 UIImagePickerController after selection cancel button bugiOS 11 UIImagePickerController 后选择取消按钮错误
【发布时间】：2018-03-27 11:53:48
【问题描述】：

我正在使用 UIImagePickerController 来选择照片并裁剪图像。

这与在 https://forums.developer.apple.com/thread/88286

这是我的代码：

- (void) onTest:(UIButton *)btn {
    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;
    picker.delegate = self;
    picker.allowsEditing = YES;
    [picker setModalPresentationStyle: UIModalPresentationOverCurrentContext];
    [self presentViewController:picker animated:YES completion:nil];
}

这是视图层。我没有添加这个 UIView。我无法按下取消按钮，也无法放大/缩小。

iOS 10 没有问题。我只有 iOS 11 有问题。

【问题讨论】：

您是否尝试过bringSubViewToFront: 选择器将其带到此视图的前面以阻止触摸？
你最后找到解决方案了吗？

标签： ios objective-c iphone uiimagepickercontroller ios11

【解决方案1】：

使用此代码打开照片库：

        UIImagePickerController *pickerView = [[UIImagePickerController alloc] init];
        pickerView.allowsEditing = YES;
        pickerView.delegate = self;
        [pickerView setSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
        [self presentViewController:pickerView animated:YES completion:nil];

并使用此委托将裁剪后的图像发送到您的视图控制器：

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
    UIImage *chosenImage = info[UIImagePickerControllerEditedImage];
    UIImage *image = chosenImage;
   [picker dismissViewControllerAnimated:YES completion:NULL];

}

【讨论】：

【解决方案2】：

我有一个好主意来解决这个问题。

将控制器（从中显示UIImagePickerController）设置为UIImagePickerController 的委托，然后符合UINavigationControllerDelegate，因为UIImagePickerController 是UINavigationController 的子类，然后实现方法：

- (void)navigationController:(UINavigationController *)navigationController didShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
  if ([UIDevice currentDevice].systemVersion.floatValue < 11) {
    return;
  }
  if ([viewController isKindOfClass:NSClassFromString(@"PUPhotoPickerHostViewController")]) {
    weakify(viewController);
    [viewController.view.subviews enumerateObjectsUsingBlock:^(__kindof UIView * _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
      if (obj.frame.size.width < 42 && FLOAT_EQUAL(obj.frame.size.height, [[UIScreen mainScreen] bounds].size.height)) {
        strongify(viewController);
        [viewController.view sendSubviewToBack:obj];
        *stop = YES;
      }
    }];
  }
}

【讨论】：

什么是弱化、强化和 FLOAT_EQUAL？我尝试了您的解决方案，但 xcode 显示错误函数“...”的隐式声明在 C99 中无效
weakController ， FLOAT_EQUAL 是比较两个浮点值

【解决方案3】：

- (IBAction)addPhoto:(UIButton *)sender {

    UIImagePickerController *picker = [[UIImagePickerController alloc] init];
    picker.delegate = self;
    picker.allowsEditing = YES;
    picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;

    [self presentViewController:picker animated:YES completion:NULL];
 }

使用这个委托：-

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {

    [picker dismissViewControllerAnimated:YES completion:NULL];

}

【讨论】：

PUPhotoPickerHostViewController 是照片裁剪视图控制器。这个 viewController 有两个按钮。取消按钮和选择按钮。取消按钮不起作用.. PUPhotoPickerHostViewController 的取消按钮与委托无关。