How to display very long user name on text file of mobile (Android/iOS)

Please help me.

I'm creating test case to test for application on mobile (Android/iOS). Screen only display at land scape status.

In case, In database have account with user = long text (ex: HaPhamHaPhamHaPhamHaPhamHaPhamHaPhamHaPhamHaPhamHaPhamHaPham).

When open app, will load data from DB to view. With this case, text field to view user can not display full text.

In this case, how to show reasonable?

Thanks you.