Open activity as pop-up and not in other screen in Android?

I am working with Bluetooth Chat sample code. In sample app the Device opens up in another screen but I have implemented the same code with the difference that DeviceListActivity is called as soon as the app is started but this opens it in another screen and I want that it should be opened as pop-up in Bluetooth chat sampl开发者_如何学Goe code.

Can someone let me know how to open Activity as pop-up?

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in your manifest file, set your activity theme to dialog

 <activity android:theme="@android:style/Theme.Dialog">