Android Question Strange behaviour when using Activity.Finish

Hi Everyone,

I'm experiencing some strange behaviour when using Activity.Finish

I have an app that has a Main activity and it calls another activity called Students using a button. I compile and install the app. When I run the app from the Open button of the installer I tap the Students button to display the Students activity. When I tap a button the has Activity.Finish the app closes and any coding in the Activity_Resume sub procedure is not executed. The same thing happens when I tap the phone's Back button.

I placed toast messages in Activity_Resume and in Activity_Pause and Activity_Resume is displayed when running the app and Activity_Pause is displayed when calling the Students activity so at least I know those parts are working. When the toast messages are in those sub routines using Activity.Finish does work once in a while. It's intermittent.

I checked the phone's storage and there was 6.52GB left. The external SD card has 537MB available.

What is the proper way to start the Main activity then call the Students activity and return back to the Main activity without exiting the app?

Thanks.