UIAlertView / Controller的Autolayout错误？

Question

我正在尝试为每个方向切换项目的Autolayout约束，并且通过以编程方式删除和添加NSAutoLayoutConstraints的纵向和横向集来实现。我对两个方向的布局都有正确的自动布局约束（我认为）。我的故事板是不使用大小类来实现兼容性。

我已截取正确布局的屏幕截图。红色部分是UIView红色。

人像布局

景观布局

我的viewWillLayoutSubviews：是

- (void)viewWillLayoutSubviews {
    [self.termToolbar invalidateIntrinsicContentSize];
}

添加和删除的所有约束都在updateViewConstraints

中

以纵向方向启动应用程序然后旋转到横向时，出现约束错误：

2015-07-26 10:50:42.856 reproduce[1084:23311] 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) 
(
    "<_UILayoutSupportConstraint:0x786436c0 V:[_UILayoutGuide:0x7864cb70(20)]>",
    "<_UILayoutSupportConstraint:0x78643680 V:|-(0)-[_UILayoutGuide:0x7864cb70]   (Names: '|':UIView:0x7864ca90 )>",
    "<NSLayoutConstraint:0x78657bc0 'UIView-Encapsulated-Layout-Width' H:[UIView:0x7864ca90(480)]>",
    "<NSLayoutConstraint:0x78657bf0 'UIView-Encapsulated-Layout-Height' V:[UIView:0x7864ca90(320)]>",
    "<NSLayoutConstraint:0x786593c0 V:[_UILayoutGuide:0x7864cb70]-(0)-[UISearchBar:0x78a21a70]>",
    "<NSLayoutConstraint:0x786593f0 V:[UISearchBar:0x78a21a70]-(0)-[UITableView:0x7982aa00]>",
    "<NSLayoutConstraint:0x78659420 V:[UITableView:0x7982aa00]-(0)-[UIView:0x78a216f0]>",
    "<NSLayoutConstraint:0x78620570 V:[UIView:0x78a216f0]-(0)-[UIToolbar:0x78b81d00]>",
    "<NSLayoutConstraint:0x786205a0 V:[UIToolbar:0x78b81d00]-(0)-|   (Names: '|':UIView:0x7864ca90 )>",
    "<NSLayoutConstraint:0x786590a0 UIView:0x78a216f0.height == 0.75*UIView:0x78a216f0.width>",
    "<NSLayoutConstraint:0x786596d0 H:|-(0)-[UIView:0x78a216f0]   (Names: '|':UIView:0x7864ca90 )>",
    "<NSLayoutConstraint:0x78659720 H:[UIView:0x78a216f0]-(0)-|   (Names: '|':UIView:0x7864ca90 )>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x786593f0 V:[UISearchBar:0x78a21a70]-(0)-[UITableView:0x7982aa00]>

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.

请注意，我正在从纵向旋转到横向，显示的错误是纵向方向！从横向旋转到纵向时，不会发生调试输出/错误。旋转回横向会导致相同的错误。

即使出现这些错误，在我显示UIAlertView / Controller之前，视图布局对于纵向和横向都显得正常。一旦显示警报，布局就会失败并且两者纵向和横向布局都显示错误（UITableView消失，红色UIView占据整个屏幕等）。无论如果警报被解除或仍在显示都无关紧要，每次警报后布局都会失败。

我创建了一个示例项目来重现可以找到here的行为。 UI元素插座在IB中连接。所有代码都在默认的ViewController类中。知道为什么会出现这种行为，或者这是一个在AutoLayout中为方向之间的简单布局更改而导致的错误？谢谢。

肖像限制：

<NSLayoutConstraint:0x7b05cda0 V:|-(0)-[_UILayoutGuide:0x7b0648a0]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05cc30 V:[_UILayoutGuide:0x7b0648a0]-(0)-[UISearchBar:0x7b0e9590]>,
<NSLayoutConstraint:0x7b05cc00 V:[UISearchBar:0x7b0e9590]-(0)-[UITableView:0x7cb4d600]>,
<NSLayoutConstraint:0x7b05cbd0 V:[UITableView:0x7cb4d600]-(0)-[UIView:0x7b0e9210]>,
<NSLayoutConstraint:0x7b05cba0 V:[UIView:0x7b0e9210]-(0)-[UIToolbar:0x7b069f10]>,
<NSLayoutConstraint:0x7b05cb70 V:[UIToolbar:0x7b069f10]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05ced0 UIView:0x7b0e9210.height == 0.75*UIView:0x7b0e9210.width>,
<NSLayoutConstraint:0x7b05c990 H:|-(0)-[UISearchBar:0x7b0e9590]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c940 H:[UISearchBar:0x7b0e9590]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c8a0 H:|-(0)-[UIView:0x7b0e9210]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c850 H:[UIView:0x7b0e9210]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c780 H:|-(0)-[UITableView:0x7cb4d600]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c730 H:[UITableView:0x7cb4d600]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c6c0 H:|-(0)-[UIToolbar:0x7b069f10]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c670 H:[UIToolbar:0x7b069f10]-(0)-|   (Names: '|':UIView:0x7b064990 )>

景观限制：

<NSLayoutConstraint:0x7b05c530 V:|-(0)-[_UILayoutGuide:0x7b0648a0]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c4e0 V:[_UILayoutGuide:0x7b0648a0]-(0)-[UISearchBar:0x7b0e9590]>,
<NSLayoutConstraint:0x7b05c4b0 V:[UISearchBar:0x7b0e9590]-(0)-[UIView:0x7b0e9210]>,
<NSLayoutConstraint:0x7b05c480 V:[UIView:0x7b0e9210]-(0)-[UIToolbar:0x7b069f10]>,
<NSLayoutConstraint:0x7b05c450 V:[UIToolbar:0x7b069f10]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c290 V:|-(0)-[_UILayoutGuide:0x7b0648a0]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c240 V:[_UILayoutGuide:0x7b0648a0]-(0)-[UISearchBar:0x7b0e9590]>,
<NSLayoutConstraint:0x7b05c210 V:[UISearchBar:0x7b0e9590]-(0)-[UITableView:0x7cb4d600]>,
<NSLayoutConstraint:0x7b05c1e0 V:[UITableView:0x7cb4d600]-(0)-[UIToolbar:0x7b069f10]>,
<NSLayoutConstraint:0x7b05c1b0 V:[UIToolbar:0x7b069f10]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05bf70 H:|-(0)-[UITableView:0x7cb4d600]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05bf20 H:[UITableView:0x7cb4d600]-(0)-[UIView:0x7b0e9210]>,
<NSLayoutConstraint:0x7b05bef0 H:[UIView:0x7b0e9210]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05c2f0 UIView:0x7b0e9210.height == 0.75*UIView:0x7b0e9210.width>,
<NSLayoutConstraint:0x7b05be30 H:|-(0)-[UISearchBar:0x7b0e9590]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05bde0 H:[UISearchBar:0x7b0e9590]-(0)-|   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05bd70 H:|-(0)-[UIToolbar:0x7b069f10]   (Names: '|':UIView:0x7b064990 )>,
<NSLayoutConstraint:0x7b05bd20 H:[UIToolbar:0x7b069f10]-(0)-|   (Names: '|':UIView:0x7b064990 )>

Answer 1

我还为此提交了一份Apple Bug Report和TSI，并得到了很好的答案。

在设备返回方向更改之前调用的方法的解决方案取决于您要支持的iOS版本。

iOS＆lt; 8 willRotateToInterfaceOrientation:

- (void)willRotateToInterfaceOrientation:(UIInterfaceOrientation)toInterfaceOrientation duration:(NSTimeInterval)duration
{
    [super willRotateToInterfaceOrientation:toInterfaceOrientation duration:duration];

    [self.view setNeedsUpdateConstraints];
}

iOS 8 + viewWillTransitionToSize: 和一些检查，以确定我们在哪个方向。

- (void)viewWillTransitionToSize:(CGSize)size withTransitionCoordinator:(id<UIViewControllerTransitionCoordinator>)coordinator
{
    if (size.width < size.height && self.view.bounds.size.width > self.view.bounds.size.height) {
        [NSLayoutConstraint deactivateConstraints:landscapeConstraints];
    } else if (size.width > size.height && self.view.bounds.size.width < self.view.bounds.size.height) {
        [NSLayoutConstraint deactivateConstraints:portraitConstraints];
    }
    [self.view setNeedsUpdateConstraints];
}