Android – how do I refresh the last activity after pressing the back button?

I'm building an alarm application. I currently have a listactivity that displays a list of alarms and another activity that changes the time of a specific alarm. My problem is that it won't refresh when I decide to enter the activity to change the time of the alarm clock and then press the back button. However, I have implemented a button to redirect back to listactivity. If I press it, Will refresh the alarm list. How do I refresh the alarm list after pressing the back button?

resolvent:

You should override onresume() to check if the alert list has been refreshed so that it is updated whenever you enter / return to listactivity