How to Set Activity as Dialog in android

Simply use this Below Code to Set Activity as Dialog.
Using android:theme="@android:style/Theme.Dialog"
                                          (OR)  
 android:theme="@android:style/Theme.Holo.Dialog"

attribute in activity tag we can define our activity appear as a dialog.

<activity
            android:name="com.androidsurya.DialogActivity"
            android:theme="@android:style/Theme.Dialog" >