Application Life Cycle

• Application is launched until it is deactivated.

• Only one application run at a time in windows phone, This model execution is designed for provide a faster, responsive any time.

• This way to prevent the device from being slow or unresponsive due to running background application.

Terminologies for Application State:

Tombstoning :

• Operating System deactivates the application process or use exits application.

• Operating System preserves any information about application’s state.

• When the application is re-launched, operating system restarts the process and sends the last known state from the application

Page State:

• Page State completely related to application page.

• It’s includes scroll positions or text fields content.

• We can modify page state is done by overriding OnNavigatedTo or OnNavigatedFrom methods.

Application State:

• It’s maintained state of application.

• we can modified Application State using PhoneApplicationService class

Persistent (Preserved) Data:

• Persistent Data is stored and retrieved from Isolated Storage.

Transient (Temporary) State:

• Transient Data is stored in State Dictionary provided by PhoneApplicationService.

• When application reactivated, Tombstoned state will be return to Transient State.

Which Events are fired in Application Lifecycle ?

Four events are fired in application lifecycle process.

• Launching

• Deactivated

• Activated

• Closing

• Launching:
• When:
• when new instance created of application, at the time Launching event is raised.
• Process:
• Run application from installed application list or from Tiles in start screen.
• Advice
• In Launching event, should not retrieve any data from Isolated Storage, because application will be slow down.
• Only create instance for application
• Deactivated:
• When:
  • When running application is closed by another application, it will be deactivated.
  • When pressing the START button.
  • Due to timeout when main screen locked.
  • Application can also be deactivated by invocation of a Launcher or Chooser or taking picture or sending emails.
• Do:
  • Application should stored information regarding the current state using State property on PhoneApplicationService
  • No guarantee that application Tombstoned condition will be reactivated, so application data should stored into Isolated.
• Advice:
• The whole action has to be finished within 10 sec, Otherwise operating system will not terminate the application, then application failed Certification.
• Activated:
  • When:
  • Application will be activated from Tombstoned condition.
  • Do:
  • Application should load data from PhoneApplicationService.
  • Advice
  • Similar to Launching event, application should not access resources from network or isolated storage to avoid the process down.
• Closing:
  • When:
  • When user press back button from application’s initial page
  • Do:
  • Application has to store persistent data into Isolated Storage.
  • Advice
  • No need to store transient data.