fill_parent -1 The view should be as big as its parent (minus padding). This constant is deprecated starting from API Level 8 and is replaced by match_parent.
match_parent -1 The view should be as big as its parent (minus padding). Introduced in API Level 8.
wrap_content -2 The view should be only big enough to enclose its content (plus padding).
从Android 2.2开始FILL_PARENT改名为MATCH_PARENT ,定义本质是一样均为-1,只是换了个别名。
参考文章:
http://blog.csdn.net/junjieking/article/details/7067855
http://blog.sina.com.cn/s/blog_4ca9ceef0100zwc9.html