我将 UIAlertController 呈现为操作表，并带有一个按钮，该按钮应在选择时打开 ActivityView....
这两种方法都在同一个 ViewController 类中......并且在 iphone 8、iPhone Pro 11 Max 等上运行良好。但在 iPad 上测试时失败。（全部运行 13.5）
最初的失败是 popoverPresentationController 没有设置 sourceview 或 barbuttonitem （或类似的东西），所以我添加了以下行：
activityViewController.popoverPresentationController.sourceView = [self view];
到分享方法。这让我过去了……所以，现在 IPAD 不会因 GenericException 崩溃……但它也不会出现 activityView。它只是抛出了一堆似乎与试图显示的 ActivityView 相关的约束违规，
[LayoutConstraints] Unable to simultaneously satisfy constraints.
Probably at least one of the constraints in the following list is one you don't want.
Try this:
(1) look at each constraint and try to figure out which you don't expect;
(2) find the code that added the unwanted constraint or constraints and fix it.
(
"<NSLayoutConstraint:0x6000000d2580 LPLinkView:0x7fda08498900.leading == UILayoutGuide:0x600001a39dc0'UIViewLayoutMarginsGuide'.leading (active)>",
"<NSLayoutConstraint:0x6000000d23f0 H:[LPLinkView:0x7fda08498900]-(59)-| (active, names: '|':_UIActivityContentTitleView:0x7fda08493b90 )>",
"<NSLayoutConstraint:0x6000000cf660 H:|-(0)-[_UIActivityContentTitleView:0x7fda08493b90] (active, names: '|':_UINavigationBarContentView:0x7fda085d5550 )>",
"<NSLayoutConstraint:0x6000000cf6b0 _UIActivityContentTitleView:0x7fda08493b90.trailing == _UINavigationBarContentView:0x7fda085d5550.trailing (active)>",
"<NSLayoutConstraint:0x6000000d08c0 'UIView-Encapsulated-Layout-Width' _UINavigationBarContentView:0x7fda085d5550.width == 0 (active)>",
"<NSLayoutConstraint:0x6000000d2260 'UIView-leftMargin-guide-constraint' H:|-(16)-[UILayoutGuide:0x600001a39dc0'UIViewLayoutMarginsGuide'](LTR) (active, names: '|':_UIActivityContentTitleView:0x7fda08493b90 )>"
)
但我对此没有设置任何限制......以及关于引用我的应用程序没有或使用的导航栏的投诉区域。这些约束必须来自一些仅与 IPAD 相关的默认设置。有谁知道我需要在这里做什么才能在 IPAD 上解决这个问题？为什么地狱是与我从未设置的东西相关的默认约束。我只设置了sourceView。
-(UIAlertController *)displayActionSheet
{
UIAlertController *sheet = [UIAlertController
alertControllerWithTitle:nil
message:nil
preferredStyle:UIAlertControllerStyleActionSheet];
.
.
.
UIAlertAction *share = [UIAlertAction
actionWithTitle:NSLocalizedString(@"Share with Friends", @"Share with Friends")
style:UIAlertActionStyleDefault
handler:^(UIAlertAction *action){
[self share];
}];
[sheet addAction:share];
.
.
.
[sheet popoverPresentationController].sourceView = [self view];
sheet.popoverPresentationController.permittedArrowDirections = 0;
[sheet popoverPresentationController].sourceRect = CGRectMake(view.bounds.size.width/2, view.bounds.size.height/2, 0, 0);
[self presentViewController:sheet animated:YES completion:nil];
return sheet;
}
-(void)share
{
NSString *shareString = @"a string to share";
UIImage *shareImage = [UIImage imageNamed:@"animagetoshare"];
NSURL *shareUrl = [NSURL URLWithString:@"a url to share"];
NSArray *activityItems = [NSArray arrayWithObjects:shareString, shareImage, shareUrl, nil];
UIActivityViewController *activityViewController = [[[UIActivityViewController alloc]
initWithActivityItems:activityItems applicationActivities:nil] autorelease];
activityViewController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
activityViewController.excludedActivityTypes = @[UIActivityTypePrint,
UIActivityTypeCopyToPasteboard, UIActivityTypeAssignToContact,
UIActivityTypeSaveToCameraRoll, UIActivityTypeAddToReadingList];
activityViewController.popoverPresentationController.sourceView = [self view];
[self presentViewController:activityViewController animated:YES completion:nil];
}