我试图将UILabel固定在它的父母单元上.我添加了四个约束(顶部,前导,尾随,底部),在iOS 8.0上可以正常工作,但不在iOS 7.X上.请看下图：
我究竟做错了什么？请指教！
编辑#1
似乎它只是因为Xcode 6通用汽车破碎了.我的方法在Xcode 6 beta 7中正常工作.
此外,如果我减小内部视图的宽度,它会引发以下警告：
2014-09-10 19:58:28.109 Test[57827:60b] 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:0x799573a0 H:|-(8)-[UIView:0x798a86e0] (Names: '|':UIView:0x798ae5d0 )>","<NSLayoutConstraint:0x799573d0 H:[UIView:0x798a86e0]-(43)-| (Names: '|':UIView:0x798ae5d0 )>","<NSAutoresizingMaskLayoutConstraint:0x798a8b00 h=--& v=--& H:[UIView:0x798ae5d0(50)]>"
)
Will attempt to recover by breaking constraint
<NSLayoutConstraint:0x799573d0 H:[UIView:0x798a86e0]-(43)-| (Names: '|':UIView:0x798ae5d0 )>
Break on objc_exception_throw to catch this in the debugger.
The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in <UIKit/UIView.h> may also be helpful.
