Hello I have tried to override the theme to the dialogFragment for fullscreen but the full screen I wanted was an overlay on top of the previous activity so when the dialogFragment is opened, we still can see back activity from the padding between the screen and the dialogFragment.
This is the style I have used for full screen
<style name="fullscreen_dialog" parent="android:Theme" >
You could just manually set the layout params in code like so. Hope it helps ! :). Also check it this SO Adjusting size of custom dialog box in android
Window window = myDialog.getWindow(); window.setLayout(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);