Final answer:
Android calls the onUpdate() method of the app widget when the user adds it to the Home screen. The onUpdate() method is responsible for updating the widget's view.
Step-by-step explanation:
When a user adds an app widget to the Home screen on Android, the operating system calls the onUpdate() method of the app widget. This method is responsible for updating the widget's view and is called whenever the widget needs to be refreshed, such as when the screen is turned on or when a configuration change occurs.
The onUpdate() method receives a RemoteViews object as a parameter, which is used to define the appearance and behavior of the widget. This allows developers to customize the widget's layout, handle user interaction, and update the displayed information as needed.
By implementing the onUpdate() method, developers can ensure that their app widget's view is always up-to-date and provides a seamless user experience.