MobileMessageBox.Show
From Xojo Documentation
Method
Displays the message box. This is not modal, so your code continues to run. When the user selects a button, the Pressed event handler is called.
Sample Code
Displays a message box. HelloMessage is a MobileMessageBox that was dragged onto the Screen from the Library:
HelloMessage.Title = "Hello"
HelloMessage.Message = "Hello, World!"
HelloMessage.Show // Not modal, so code does not pause here
HelloMessage.Message = "Hello, World!"
HelloMessage.Show // Not modal, so code does not pause here