UIActivityViewController，無法同時滿足約束，在設備上時8.x的編譯爲iOS 7.x的

Question

我有一個上的UIViewController所示（名爲viewCon這裏）的UIActivityViewController：

// items contains text and/or image 
UIActivityViewController *activityViewController = [[UIActivityViewController alloc] initWithActivityItems:items applicationActivities:nil]; 
activityViewController.excludedActivityTypes = @[UIActivityTypePostToWeibo, UIActivityTypeAssignToContact]; 

[viewCon presentViewController:activityViewController animated:YES completion:NULL]; 

我使用Xcode 6.1。我的應用的部署目標爲7.0。我在兩個物理iPhone（5S（8.0.2）和6（8.1））上運行它。
當我在物理設備（不是模擬器）上編譯iOS 7.x的應用程序時，將顯示UIActivityViewController並且可以正常工作，但它會顯示在所有屏幕上（高度過大），並且此日誌消息將打印在輸出：

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. 
(Note: If you're seeing NSAutoresizingMaskLayoutConstraints that you don't understand, refer to the documentation for the UIView property translatesAutoresizingMaskIntoConstraints) 
(
"<NSLayoutConstraint:0x1742941e0 UIView:0x174385960.bottom == _UIAlertControllerView:0x134ef4fc0.bottom>", 
"<NSLayoutConstraint:0x174293d80 V:|-(0)-[UIView:0x170385960] (Names: '|':_UIAlertControllerView:0x134ef4fc0)>", 
"<NSLayoutConstraint:0x17429a270 UIView:0x170385960.bottom <= _UIAlertControllerView:0x134ef4fc0.bottom>", 
"<NSLayoutConstraint:0x174292cf0 UIView:0x174385960.centerY == UIView:0x170385960.centerY>", 
"<NSLayoutConstraint:0x174294410 V:|-(>=8)-[UIView:0x174385960] (Names: '|':_UIAlertControllerView:0x134ef4fc0)>" 
) 

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x17429a270 UIView:0x170385960.bottom <= _UIAlertControllerView:0x134ef4fc0.bottom> 

Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger. 
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful. 

當我編譯和運行的iOS 8.x一切正常。但我當然需要爲iOS 7.x編譯兼容性。
UIViewController使用使用Autolayout的.xib。但我試圖不使用Autolayout並出現同樣的問題。我嘗試了另外兩個項目，也在iOS 7上，它仍然是一樣的。

我也試圖呈現activityViewController前添加以下代碼，但同樣的問題：

[activityViewController.view setTranslatesAutoresizingMaskIntoConstraints:NO]; 

我看着別人的開發人員有同樣的問題（here），但它是由Xcode的6公測引起的。我有版本6.1。

Answer 1

我想這是一個iOS7的錯誤。 它帶有一些特殊的sourceRect值。 您可以通過集中的另一個sourceRect解決這個問題，例如，你可以嘗試：

[activityView popoverPresentationController].sourceRect=CGRectMake(0,200,768,20);