title: Android override default dialog theme
body: <p>I want to create a custom style for an activity that will look like a dialog. But i want to put this dialog at the top right of the screen, and also set is background to transparent.</p>
  
  <p>I have setted the activity theme to @android:style/Theme.Dialog but now i want to override the existing theme but i have not found this theme in my sdk folder.</p>
  
  <p>Can someone tell me how can i change the default dialog theme?</p>