How to automate OAuth login screen for a Native app in iPhone device?

Unable to spy objects in OAuth login page for a Native app installed in iPhone device. Object Spy properties dialog box opened in Native (non-instrumented) mode.

Nature of the login screen:-
After launching the application and entered the credentials in the login screen by manually, the endpoint of the login screen hits the safari browser and once it is authenticated, then it is re-directed to the native app.

Kindly help on this issue.