I want to change basicTheme instead of the initial thing "Theme.Black.NoTitleBar.Fullscreen."

I spent all day finding the way to change the theme.

The reason why I did this thing is to change the style of “AlertDialog” I used in the game.

These are what I tried to do.

A. styles.xml in ‘values’ folder
In order to get rid of the basic theme style,
I changed it

<style name=“UE4BaseTheme” parent = “@android:style/Theme.Black.NoTitleBar.Fullscreen” />

to

<style name=“UE4BaseTheme”>
<item name=“android:windowNoTitle”>true</item>
<item name=“android:windowFullscreen”>true</item>
</style>

B. styles.xml files in values-land and values-port folders
I removed this line below.
<style name=“UE4BaseTheme” parent = “@android:style/Theme.Black.NoTitleBar.Fullscreen” />

Not work at all!!!

I must miss something.

Anyone help me. Thanks.