自動布局 Autolayout 報錯：Unable to simultaneously satisfy constraints.

在使用自動布局時，不斷的報下面的錯誤：

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:0x8c67c10 V:[UIButton:0x8c67320]-(2)-|   (Names: '|':UIView:0x8c65ad0 )>",

    "<NSAutoresizingMaskLayoutConstraint:0x8e166b0 h=--& v=--& UIButton:0x8c67320.midY ==>",

    "<NSAutoresizingMaskLayoutConstraint:0x8e166e0 h=--& v=--& V:[UIButton:0x8c67320(0)]>",

    "<NSAutoresizingMaskLayoutConstraint:0x8e130d0 h=-&- v=-&- UIView:0x8c65ad0.height == PicCollectionViewCell:0x8c65a00.height>",

    "<NSLayoutConstraint:0x8e13710 'UIView-Encapsulated-Layout-Height' V:[PicCollectionViewCell:0x8c65a00(100)]>"

)

Will attempt to recover by breaking constraint 

<NSLayoutConstraint:0x8c67c10 V:[UIButton:0x8c67320]-(2)-|   (Names: '|':UIView:0x8c65ad0 )>

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.

這種錯誤，一般就兩個原因：1，你的限制的确設定錯誤；2，忘記設定控件的：setTranslatesAutoresizingMaskIntoConstraints 等于NO 。

我就屬于第二種情況，其實錯誤資訊裡也寫的很清楚了，NSAutoresizingMaskLayoutConstraint:0x8e166e0 。