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。
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