iOS 13 UIActivityViewController 保存图片后自动呈现上一张VC

Question

我正在尝试实现“将图像保存到库”功能，然后 return 返回到当前视图控制器，但是在新的 iOS 13 上它返回到视图控制器出示当前的：

PHPhotoLibrary.requestAuthorization({(_ status: PHAuthorizationStatus) -> Void in })

let shareItems: Array = [newImg,"Hello"] as [Any]

let activityController = UIActivityViewController(activityItems: shareItems, applicationActivities: nil)

if UIDevice.current.userInterfaceIdiom == .pad {
    activityController.popoverPresentationController?.sourceView = saveButton
}

present(activityController, animated: true)

Answer 1

我通过将根视图控制器设置为当前 window 解决了这个问题，我不知道为什么它会关闭当前视图控制器。我注意到，在 iOS 13 中呈现新的视图控制器时，它将以卡片堆叠样式呈现，如果我在 UIActivityController 中选择 "Save Image"，则当前视图控制器（卡片）将被关闭并显示前一个视图控制器。

guard let appDelegate = UIApplication.shared.delegate as? AppDelegate,
      let window = appDelegate.window else { return }
window.rootViewController = viewcontroller

当我需要开始一个新故事时，我使用这个而不是呈现视图控制器。

顺便说一句，这取决于您的要求。在这种情况下，我可以关闭旧的未使用的，因为不需要返回，也许您可以使用它来代替呈现新场景。

Answer 2

这是我目前解决此错误的方法。我创建了一个假视图控制器并将其推送到当前堆栈。似乎 UIActivityTypeSaveToCameraRoll 取消了堆栈上的顶视图控制器，而其他选项则没有。如果 activity 类型不完整且 UIActivityTypeSaveToCameraRoll.

，我会在完成块中关闭假视图控制器

typeof(self) __weak weakSelf = self;

[self.activityViewController setCompletionHandler:^(NSString *activityType, BOOL completed) {
        if (activityType== UIActivityTypeSaveToCameraRoll && completed){
              weakSelf.activityViewController = nil;
        }
        else{
             [weakSelf dismissViewControllerAnimated:NO completion:nil];
             weakSelf.activityViewController = nil;       
        }
}];


UIViewController *fakeVC=[[UIViewController alloc] init];

[self presentViewController:fakeVC animated:NO completion:^{
       [fakeVC presentViewController:self.activityViewController animated:YES completion:nil];
}];

Answer 3

我生成了以下猴子补丁（由 iOS 13.1.2 检查）

- (void)export {

  //
  // ... Generate Your Activity Items ...
  //

  UIActivityViewController *activityViewController = [[UIActivityViewController alloc] initWithActivityItems:activityItems
                                                                                           applicationActivities:nil
                                                                                                   completeBlock:^(NSError *activityError, BOOL completed) {
                                                                                                       // Swizzling Dismiss Method
                                                                                                       [[self class]   switchInstanceMethodFrom:@selector(dismissViewControllerAnimated:completion:) To:@selector(lockedDismissViewControllerAnimated:completion:)];
                                                                                                   }
                                                                                ];
  // Swizzling Dismiss Method
  [[self class] switchInstanceMethodFrom:@selector(dismissViewControllerAnimated:completion:) To:@selector(lockedDismissViewControllerAnimated:completion:)];
  [self presentViewController:activityViewController animated:YES completion:nil];
}

- (void)lockedDismissViewControllerAnimated:(BOOL)flag completion:(void (^)(void))completion {
    if ([self presentedViewController]) {
        [self lockedDismissViewControllerAnimated:flag completion:completion];
    }
}

// from http://qiita.com/paming/items/25eaf89e4f448ab05752
+(void)switchInstanceMethodFrom:(SEL)from To:(SEL)to
{
    Method fromMethod = class_getInstanceMethod(self,from);
    Method toMethod   = class_getInstanceMethod(self,to  );
    method_exchangeImplementations(fromMethod, toMethod);
}

Answer 4

- (UIWindow *)displayWindow
{
    if (!_displayWindow)
    {
        _displayWindow = [[UIWindow alloc] initWithFrame:UIScreen.mainScreen.bounds];
        _displayWindow.rootViewController = [[UIViewController alloc] init];
    }
    return _displayWindow;
}

- (void)showActivityController
{
    UIActivityViewController *activityViewController = [[UIActivityViewController alloc] initWithActivityItems:@[] applicationActivities:nil];
    activityViewController.completionWithItemsHandler = ^(UIActivityType __nullable activityType, BOOL completed, NSArray * __nullable returnedItems, NSError * __nullable activityError)
    {
        [UIApplication.sharedApplication.delegate.window makeKeyAndVisible];
    };

    [self.displayWindow makeKeyAndVisible];
    [self.displayWindow.rootViewController presentViewController:activityViewController animated:true completion:nil];
}

确保 _displayWindow 是强引用。

Answer 5

Swift @KDP 解决方案的版本：

let fakeViewController = TransparentViewController()
fakeViewController.modalPresentationStyle = .overFullScreen

activityViewController.completionWithItemsHandler = { [weak fakeViewController] _, _, _, _ in
    if let presentingViewController = fakeViewController?.presentingViewController {
        presentingViewController.dismiss(animated: false, completion: nil)
    } else {
        fakeViewController?.dismiss(animated: false, completion: nil)
    }
}
present(fakeViewController, animated: true) { [weak fakeViewController] in
    fakeViewController?.present(activityViewController, animated: true, completion: nil)
}

fakeViewController 要么被 activity 完成解雇，要么我们需要在完成时解雇它。

Answer 6

我可以确认这个错误在 iOS 13.3.1 中仍然存在。以下解决方法是的 Swift 版本。我更喜欢这种方法，因为它不对视图控制器层次结构做任何进一步的假设，也不使用方法调配。

使用这个额外的 UIWindow 会破坏 iOS 12 和更早版本上 UIActivityViewController 的 Cancel 按钮，所以我添加了一个检查OS 版本。

private let activityWindow: UIWindow = {
  let window = UIWindow(frame: UIScreen.main.bounds)
  window.rootViewController = UIViewController()
  return window
}()

func showActivityController() {
  let activityViewController = UIActivityViewController(/* ... */)
  activityViewController.completionWithItemsHandler = {
     // ...
     UIApplication.shared.delegate?.window??.makeKeyAndVisible()       
  }

  // Use this workaround only on iOS 13
  if ProcessInfo.processInfo.operatingSystemVersion.majorVersion == 13 {
    activityWindow.makeKeyAndVisible()
    activityWindow.rootViewController?.present(activityViewController, animated: true)
  } else {
    present(activityViewController, animated: true)
  }
}

更新： 显然，此解决方案不能在 iPad 上可靠地工作。看起来 iPad 和 UIActivityViewController 的显示方式有所不同，只要它在屏幕上可见，就不会注册任何触摸事件，从而有效地冻结了应用程序。

Answer 7

对于那些在 iPad 上屏幕冻结的用户，这里有一个简单的解决方案。它也适用于 iPhone。

func shareItems(_ sharedItems: [Any]) {

        let activityViewController = UIActivityViewController(activityItems: sharedItems, applicationActivities: nil)
        if let popoverController = activityViewController.popoverPresentationController {
            popoverController.sourceRect = CGRect(x: UIScreen.main.bounds.width / 2, y: UIScreen.main.bounds.height / 2, width: 0, height: 0)
            popoverController.sourceView = self.view
            popoverController.permittedArrowDirections = UIPopoverArrowDirection(rawValue: 0)
        }

        self.present(activityViewController, animated: true, completion: nil)
}

Answer 8

似乎已在 iOS 14 中修复。对于旧版本，我发现通过使用空实现覆盖 dismiss(animated:) 方法更容易解决。参见

iOS 13 UIActivityViewController 保存图片后自动呈现上一张VC

iOS 13 UIActivityViewController automatically present previous VC after image saving

ios

uiactivityviewcontroller

swift

ios13