The lifecycle of a mobile app is more complex and different from a desktop app. On a mobile device an application runs either in the foreground or in the background. When a phone calls arrive or when user opens another app, our app is going to background. If you are a programmer, you might be interested in responding to changes in the application state, for example saving current app state when your app goes into the background or refreshing the screen after moving into foreground. Main two m...