安卓-topic 通知 Toast
http://developer.android.youdaxue.com/guide/topics/ui/notifiers/toasts.html#Positioning
创建自定义 Toast View
To create a custom layout, define a View layout, in XML or in your application code, and pass the root View object to the setView(View) method.
For example, you can create the layout for the toast visible in the screenshot to the right with the following XML (saved as layout/custom_toast.xml):