In Android, the customer has implemented the Facebook login using MAG and Mobile SDK.
During the social login flow, when the users are redirect to native app. the user wants to customize this screen. If so, how could we do that?
The Mobile SDK uses Android AppAuth (https://github.com/openid/AppAuth-Android) to launch the Custom Chrome Tab, the section: https://github.com/openid/AppAuth-Android#obtaining-an-authorization-code explains how to directly transit to another activity on completion or cancellation.
You can reference to the MASUI implementation under
https://github.com/CAAPIM/Android-MAS-SDK/blob/Stable/masui/src/main/java/com/ca/mas/ui/MASCustomTabs.java, you can replace the MASOAuthRedirectActivity with your custom activity.