android hasExtra的用法

public boolean hasExtra (String name)

Added in API level 1

Returns true if an extra value is associated with the given name.

Parameters

namethe extra's name

Returns

• true if the given extra is present.

Intent intent = getIntent();Log.i("TAG1", intent.hasExtra("x") + "");Log.i("TAG1", intent.hasExtra("y") + "");Log.i("TAG1", intent.hasExtra("z") + "");

个人理解是判断intent传值过来是否包含上一个页面的key值
文档解释