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I am trying to learn programming for the iPhone and I keep seeing these files and I am not sure when is each file and content of those files referred to in the execution of a program built for the iPhone. I am trying to follow tutorials and tips available online but nowhere is there a point by point comparison or something like that. It would be great if any of you could list a few basic differences like when is each file referred and what should ideally go into each file and so on. Thanks for your time already.
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The tab bar controller is configured with two tabs by default. You can delete a tab by selecting the corresponding view controller (or segue) and deleting it the storyboard. To add a tab, first drag a new View Controller object to the storybard.
The root view controller provides the content view of the window. Assigning a view controller to this property (either programmatically or using Interface Builder) installs the view controller's view as the content view of the window.
The root view controller defines the initial content seen by the user. Figure 2-1 shows the relationship between the root view controller and the window. Because the window has no visible content of its own, the view controller’s view provides all of the content.
The root view controller is the anchor of the view controller hierarchy. Every window has exactly one root view controller whose content fills that window. The root view controller defines the initial content seen by the user. Figure 2-1 shows the relationship between the root view controller and the window.
Clearly from above section, @RestController is a convenience annotation that does nothing more than adds the @Controller and @ResponseBody annotations in single statement. A key difference between a traditional MVC @Controller and the RESTful web service @RestController is the way that the HTTP response body is created.
A spring mvc controller is used typically in UI based applications where response is generally HTML content. The handler method returns the response “view name” which is resolved to a view technology file (e.g. JSP or FTL) by view resolver.
In general, delegates can be thought of as event handlers. Accordingly, the AppDelegate is the main event handler for your entire application. It is told when the application has launched, when it will exit, when a Push notification comes in, when the app has gone into the background, etc. One of those events - applicationDidFinishLaunching - is typically responsible for creating the application's window and adding views to that window.
In most applications, the view that is added to the window is actually controlled by a UIViewController. Each UIViewController is responsible for managing the appearance of one main view plus all of its subviews. For example, a UITableViewController is responsible for managing a UITableView (main view) and all of the UITableViewCells (subview) that are inserted into that UITableView. The UIViewController typically acts as a delegate (event handler) to the views it is responsible for. When a user taps a table view cell, a method in the UITableViewController is called. When the user swipes to delete a separate method is called.
A generic UIViewController provides the same basic functionality, but for custom views. For example, the UIViewController may be responsible for displaying a few text views and a button. The UIViewController would create its main view, the text views and the button view. The text views and button view would be added to the view controller's main view as subviews. The UIViewController would register itself as the delegate for events from the text view (for example learning when the user has finished editing the text in the text view). It would also register a method to handle a button press originating from the button it owned. When any of these registered events occur, methods on the UIViewController are called allowing you to take whatever action is needed.
The rootViewController is a specific type of view controller used with navigation controllers. If you want an application that has the typical iOS navigation view hierarchy, your AppDelegate would typically add a UINavigationController to the app's window. That UINavigationController is useless without actually having content to display. That is where the rootViewController comes into play. You are responsible for providing a view controller (such as the one described above) to act as the first view stored in the UINavigationController's stack of views. This view will be displayed when the app starts up and anytime that the user pops subsequent ViewControllers off of the UINavigationController's stack.
Long winded I realize - but hope it helps.
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