http://blog.sunnyxx.com/2015/05/17/cell-height-calculation/

http://www.cnblogs.com/bugly/p/5845778.html

http://www.cnblogs.com/thsk/p/5423597.html

https://www.zhihu.com/question/35947281

http://www.keakon.NET/2011/08/03/%E4%BC%98%E5%8C%96UITableView%E6%80%A7%E8%83%BD

http://www.cocoachina.com/ios/20150602/11968.html

知识看点