App Launch presentation

[ybakos]

Need to incorporate the presentation on app launch, including application entry point, top level code, main.swift, and the synthesis we get with @UIApplicationMain.

(To be referenced in RSSReader Lesson 1).

In addition, we'll want to include the storyboard unmarshaling, initial view controller instantiation, and the interaction between the app instance, delegate, window, the initial view controller, and its view.

[ybakos]

More context:
"Explain how the UIApplicationMain function instantiates a UIApplication object, assigns the app delegate to the UIApplication object delegate property, begins the main event loop, and, if configured, loads the main storyboard interface."

(Let's show, not tell.)

[ybakos]

Additional context:
"warning indicating that although view controllers exist in the storyboard, the tab controller scene is unreachable because no initial view controller has been specified."
Per warning: Unsupported Configuration: Scene is unreachable due to lack of entry points and does not have an identifier for runtime access via -instantiateViewControllerWithIdentifier:.
Lesson 2:
"Discuss how, when a project is configured with a main storyboard, the work started by the UIApplicationMain function instantiates a window, loads the main storyboard, instantiates the storyboard's initial view controller, assigns the new view controller to the window’s rootViewController property, and then makes the window visible on the screen."

[ybakos]

Summarizing this material, for Swift and modern iOS:
https://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/TheAppLifeCycle/TheAppLifeCycle.html