ios代码添加NSLayoutConstraint的问题

Q1

在工做中发现，须要代码添加NSLayoutConstraint的时候，发现出现以下问题：

Unable to simultaneously satisfy constraints.

Probably at least one of the constraints in the following list is one you don't want

‍解决方案: 设置view的translatesAutoresizingMaskIntoConstraints的属性为NO便可解决‍

Q2

出现以下问题：The view hierarchy is not prepared for the constraint:

解决方案：先将view添加到superview上，而后再添加NSLayoutConstraint约束条件便可解决