autolayout detail

1、 [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:0x17068b630 UIButton:0x153b67fe0.right == UITableViewCellContentView:0x153b682a0.right - 2   (active)>",

    "<NSLayoutConstraint:0x17068b3b0 H:|-(372)-[UIButton:0x153b67fe0](LTR)   (active, names: '|':UITableViewCellContentView:0x153b682a0 )>",

    "<NSLayoutConstraint:0x17068bf90 'UIView-Encapsulated-Layout-Width' UITableViewCellContentView:0x153b682a0.width == 320   (active)>"

)

Will attempt to recover by breaking constraint 

<NSLayoutConstraint:0x17068b630 UIButton:0x153b67fe0.right == UITableViewCellContentView:0x153b682a0.right - 2   (active)>

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.

特别注意： 

（1）打symbolic breakpoint

(2)将[b]UIViewAlertForUnsatisfiableConstraints放入位置[/b]

这样能找到异常的准确的位置



2、用了自动布局框架purelayout 
方法后newAutoLayout()，再来重新设置frame必须重新初始化，否则，无效，newAutoLayout这个方法里面关闭了frame
，这种方法实例化出来的只能用自动布局了