IOS (formerly iPhone OS) is a mobile operating system created and developed by Apple Inc.
exclusively for its hardware. It is the operating system that presently powers many of the company’s
mobile devices, including the iPhone, iPad, and iPod Touch.
It is the most popular mobile operating system globally.
> Let we start with Objective C language
*An Overview of Objective-C Object Oriented Programming.
*Installing Xcode and Compiling Objective-C on Mac OS X.
*Start Using Xcode.
->We Are learning here realtime Topics:
> Now we are learning about ViewController & its lifeCycle:
The UIViewController class defines the shared behavior that is common to all view
controllers.You rarely create instances of the UIViewController class directly. Instead,
you subclass UIViewController and add the methods and properties needed to manage the view controller’s
view hierarchy.A view controller’s main responsibilities include the following:
Updating the contents of the views, usually in response to changes to the underlying data.
Responding to user interactions with views.Resizing views and managing the layout of the overall interface.
Coordinating with other objects—including other view controllers—in your app.
ViewDidLoad : Called when you create the class and load from xib. Great for initial setup and one-time-only work.
ViewWillAppear : Called right before your view appears, good for hiding/showing fields or any operations that you want to happen
every time before the view is visible. Because you might be going back and forth between views, this will be called
every time your view is about to appear on the screen.
ViewDidAppear : Called after the view appears – great place to start an animations or the loading of external data from an API.
ViewWillDisappear/DidDisappea : Same idea as ViewWillAppear/ViewDidAppear.
ViewDidUnload/ViewDidDispose : In Objective C, this is where you do your clean-up and release of stuff, but this is handled automatically so not much you really need to do here.