how to create android popup window?

I am trying to create a popup/floating window in my app. like the android app switcher when you long press the home key. 开发者_C百科It doesnt really count as an activity.

How can this be done?

Thanks!

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Hello please search before asking go here nice tuto http://www.helloandroid.com/tutorials/how-display-custom-dialog-your-android-application