Windows 8 Metro app developers must not only create responsive software, they must also be aware of what Microsoft calls an app's "lifecycle". This term means what kind of state an app might be in while running in a Windows 8-based device. In the newest post on the official Windows 8 app developer blog, Microsoft goes over some details on how app creators can manager the lifecycle of their Metro-based software.
There are four parts to a Windows 8 Metro lifecycle: Not running, running , suspended or terminated. The chart above not only shows those lifecycles but also shows how a Metro app transitions between different states. For example, if a person switches between apps on Windows 8, the app they were using beforehand is put in the suspended lifecycle, which freezes it in memory. The app is supposed to instantly start running again when a user goes back to it.
However, it is possible that an app may stay suspended for a long time before a user goes back to it. Microsoft states:
Data or network connections could become stale and may need to be refreshed when your app resumes. When a user brings your app back to the foreground, your app receives a resuming event. You can refresh the app content and reconnect network resources when your app receives this event.
The highly technical blog entry also offers up some more tips for app makers, including resetting the app to its default view if it hasn't been used in a long time and making sure that the most important data in your Metro app is saved when it goes into its suspended lifecycle.
Image via Microsoft