This document discusses launchers and choosers in Windows Phone applications. Launchers launch built-in applications like making a phone call or sending a text message without returning any data. Choosers also launch built-in applications but do return data to the calling application, like allowing the user to select a contact. The document provides code examples and explains the application lifecycle events that occur when launchers and choosers are used, such as navigating away from the application.

1. Launchers and Choosers Jason Lee Ethos Technologies

3. Full List

4. Code Example

5. Execution Model

6. Event Flow

7. Play Time

9. Telephone Call, SMS, Email, Camera, Contacts etc.

10. Indirect access to phone features & data

11. Applications can NOT directly access information such as contacts.

12. Applications can NOT directly execute behaviors such as phone call or SMS.

13. Launchers & Choosers allow applications to access various phone features and data through them.

14. They invoke new applications

16. Launches one of the built-in applications through which a user can complete a certain task

17. No data is returned to calling application

18. Examples :

19. PhoneCallTask

21. Also launches one of the built-in applications through which a user can complete a certain task

22. Returns some data to calling application

23. When a chooser completes, calling application is reactivated and supplied with the result

24. A user can cancel the launcher, in which case an empty value is returned

25. Examples :

26. PhoneNumberChooserTask

29. Different launchers has different parameters

30. They all have a Show() method to invoke tasks

31. Example 1

33. Hook to a Chooser’s Completed event for result data

34. Use Show() method to invoke tasks

36. OnNavigatedFrom event occurs to the page

37. Deactivated event occurs to the App

38. Control switches to the task

39. While Launchers & Choosers running

40. There’s no guarantee that the user will come back to your app

41. If the user navigates away from the task, your app will be dormant, and therefore has a possibility to be tombstoned eventually

42. Thus, every stateful application should handle tombstoning

43. After Launchers & Choosers complete

44. Activated event occurs to App

45. OnNavigatedTo event occurs to the page

49. Get familiar with various Launchers and Choosers