我正在尝试实现“保存图像到相册”功能，然后返回到当前的视图控制器，但在新的 iOS 13 上，它会关闭当前的视图控制器并返回到前一个呈现它的视图控制器：
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)
@KDP的解决方案的Swift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 要么在活动完成时被解除，要么我们需要在完成时解除它。UIWindow会破坏UIActivityViewController的取消按钮，因此我添加了一个操作系统版本的检查。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，这个解决方案在iPad上不可靠。在iPad上，UIActivityViewController的呈现方式似乎不同，一旦它出现在屏幕上，就无法注册触摸事件，从而导致应用程序冻结。
UIActivityViewController 的方法。然后，不要调用 present(activityViewController, animated: true)，而是调用 showActivityViewController()。 - Theoref.show(); 在我的情况下，我必须先添加 ref.hide()。我怀疑这不是你需要的，但可能会提供一些见解。 - troggy69- (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);
}
- (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。
目前，我是通过以下方式解决该bug的。我创建一个虚拟视图控制器，并将其推入当前堆栈中。似乎UIActivityTypeSaveToCameraRoll会关闭堆栈中的顶部视图控制器，而其他选项则不会。如果活动类型不是complete和UIActivityTypeSaveToCameraRoll，我会在完成块中处理关闭虚拟视图控制器的操作。
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];
}];
我通过将根视图控制器设置为当前窗口来解决了这个问题，我不知道为什么它会关闭当前的视图控制器。我注意到，在iOS 13中呈现新的视图控制器时，它会以卡堆叠样式呈现，并且如果我在UIActivityController中选择“保存图像”，则当前的视图控制器（卡）将被关闭并显示出先前的视图控制器。
guard let appDelegate = UIApplication.shared.delegate as? AppDelegate,
let window = appDelegate.window else { return }
window.rootViewController = viewcontroller
当需要开始新的故事时，我使用这个而不是呈现视图控制器。
顺便说一下，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故事，因为不需要后退，也许您可以使用这个来代替呈现新场景。
我曾经遇到过同样的问题，因此我改变了viewcontroller的显示方式。
调用分享按钮的viewcontroller对我来说存在问题。
我之前是这样调用分享按钮的viewcontoller的: enter image description here self.present(.......) 然后我进行了更改
self.view.window.rootviewcontroller = 分享按钮的viewcontoller
然后问题就解决了。
看起来在iOS 14中已经修复了。对于旧版本，我发现通过覆盖dismiss(animated:)方法并使用空实现更容易解决。请参见https://dev59.com/k7jna4cB1Zd3GeqP6DJG#66595125
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)
}