前言

在做项目的时候，无意间看到自动布局约束警告，开始也也觉得没什么，虽然有警告，但并不影响UI展示效果。但是越来越有代码洁癖的我，也忍受不了控制台输出一大堆约束警告Log，于是就查阅如何定位解决约束冲突，同时自己也记录下来。下面开始介绍具体操作步骤吧。

一、添加UIViewAlertForUnsatisfiableConstraints断点

• 添加Symbolic Breakpoints

• 编辑断点symbol填入

UIViewAlertForUnsatisfiableConstraints复制代码

• 添加控制台打印action

po [[UIWindow keyWindow] _autolayoutTrace]复制代码

二、定位约束警告冲突

• 添加好断点之后，当界面有约束冲突，就会触发断点，控制打印如下：

[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. (	
    
     ,	
     
      ,	
      
       ,	
       
        ,)Will attempt to recover by breaking constraint 
        
         Make a symbolic breakpoint at UIViewAlertForUnsatisfiableConstraints to catch this in the debugger.The methods in the UIConstraintBasedLayoutDebugging category on UIView listed in 
         
           may also be helpful.复制代码
         
        
       
      
     
    

• 根据提示，找到约束有问题的控件地址0x7faf99f04010，然后全局搜索，就能找到具体是哪个控件
• 如果控制台打印不够直观看出是哪个控件约束有问题，我们可以通过 LLDB命令工具定位寻找。

三、解决冲突

通常解决冲突的方法有：

• 删除多余约束
• 修改约束优先级

参考

1、