Android6.0运行时权限简介：http://unclechen.github.io/2016/03/05/Android6.0%E8%BF%90%E8%A1%8C%E6%97%B6%E6%9D%83%E9%99%90%E7%AE%80%E4%BB%8B/
Android6.0权限适配之WRITE_EXTERNAL_STORAGE（SD卡写入）:https://blog.csdn.net/xiechengfa/article/details/52699233
Android 6.0 运行时权限理解:https://blog.csdn.net/hehe26/article/details/52804630
1.Android6.0运行时权限简介_2.Android6.0权限适配之WRITE_EXTERNAL_STORAGE（SD卡写入）3_.Android 6.0 运行时权限理解