当我在自动搜索等搜索框中输入内容时，如何从服务器获取数据？

i trying to implement auto search mechanism in android like google. Here when i enter some words then display related search results in list view. For example i entered 3 letters then display related search results from server, again i will add another letter to previous 3 letters then automatically display related search results with out click search button.I don't know how to do it, every time api calling. How to use Search view option from android xml for searching? i trying to implement auto search mechanism in