You can create controllers in several ways.

You can create controllers in several ways.

How to Create a controller:

<Method 1> Create directly:

XZOneViewController * one = [[XZOneViewController alloc] init];
One. view. backgroundColor = [UIColor redColor];
Self. window. rootViewController = one;

 

<Method 2> Create on storyboard:

1. Actively load the storyboard (load the already described items from the existing storyboard)

// 1.0 create a storyboard file Two. storyboard first, but do not set it in Main Interface to start loading main storyboard (remove main ).

 

// 1.1 load the storyboard file without creating the controller in the storyboard.

// Nil indicates mainBundle, and operations on the storyboard object mean operations on the Two. storyboard file.
UIStoryboard * storyboard = [UIStoryboard storyboardWithName: @ "Two" bundle: nil];

 

// 1.2 create a controller in the storyboard

// Case 1 of 1.2:

// UIViewController * vc = [storyboard instantiateInitialViewController]; // The returned result is the Controller indicated by the arrow.

// Case 2 of 1.2:
UIViewController * vc = [storyboard instantiateViewControllerWithIdentifier: @ "pink"]; // This controller is a controller with no arrows pointing to, and identifier is pink

Self. window. rootViewController = vc;

// 1:

 

2. Set storyboard as the Main storyboard of the entire program. After the program is started, the Main. storyboard will be loaded:

The code for Automatically Generating and loading storyboard is:

// 1. Create a window
Self. window = [[UIWindow alloc] initWithFrame: [UIScreen mainScreen]. bounds];

// 2. Load the storyboard and create the initialization controller (Controller pointed by the arrow)
UIStoryboard * storyboard = [UIStoryboard storyboardWithName: @ "Main" bundle: nil];
Self. window. rootViewController = [storyboard instantiateInitialViewController];

// 3. display window
[Self. window makeKeyAndVisible];

 

Loading the main storyboard will accomplish three things:

1> Create a window

2> Create the Initial View Controller pointed by the arrow.

3> set the Controller as the root controller of the window. The view of the controller is displayed on the window.

 

Conclusion: 1. the storyboard does not take the initiative to load it;

2. As long as the main window is set, storyboard code is automatically generated and loaded.

<Method 3> specify the xib file to create it:

XZViewController * viewVc = [[XZViewController alloc] initWithNibName: @ "xzVc" bundle: nil]; // an xzVc has been created before. xib file. Remember to drag the view of xib to the corresponding controller (file 'owner ).

 

 

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