android仿google按字母快速查找通讯录的功能，貌似现在很多手机都有这功能，的确用起来方便，怎么实现呢？这是个例子，并不是完整的通讯录程序。-Imitation google android quickly find contacts in alphabetical functions, looks like a lot of phones now have this feature, really easy to use them, how to achieve it? This is