iOS自定义转场动画实战讲解
1 https://blog.csdn.net/cloudybird/article/details/50763312
3 https://www.jianshu.com/p/fb0d6b0f8008
4https://blog.csdn.net/yangzm/article/details/51292233
5 https://www.jianshu.com/p/a9b1307b305b
6 https://www.jianshu.com/p/45434f73019e (目前项目里用的 xw)
7http://www.cocoachina.com/articles/21621 （圆圈 扩散开动画）
8 https://www.cnblogs.com/demodashi/p/8509303.html
9 iOS-OC-可交互自定义转场动画，带你填坑
