If you want to use a custom theme for Chat SDK you need to make sure your theme inherits from the ChatSDKTheme:
Open your App's theme file in
res -> values -> styles.xml
<resources><style name="AppTheme" parent="ChatSDKTheme"></style></resources>
Then you need to disable the default Chat SDK theme:
If you want to use a completely separate theme for Chat SDK then your main project, make a new theme that has the
ChatSDKTheme as it's parent.
Then tell Chat SDK to use that theme: