https://blog.csdn.net/fengsh998/article/details/9039629
https://www.jianshu.com/p/61dff0c46ada
https://www.jianshu.com/p/d60b388b19f5
http://www.cnblogs.com/junhuawang/p/5742535.html
http://blog.sina.com.cn/s/blog_5da93c8f0102wkz9.html
https://bestswifter.com/uiviewlifetime/
