https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIViewController_Class/#//apple_ref/occ/instp/UIViewController/nibName

用xib这种方式是需要加载xib文件的。加载xib文件有两种方法：

// 第一种方法（较为常用）
CYLView *view = [[[NSBundle mainBundle] loadNibNamed:@"CYLView" owner:nil options:nil] firstObject]; // CYLView代表CYLView.xib，代表CYLView这个类对应的xib文件。这个方法返回的是一个NSArray，我们取第一个Object或最后一个（因为这个数组只有一个CYLView没有其他对象）就是需要加载的CYLView。

// 第二种方法
UINib *nib = [UINib nibWithNibName:@"CYLView" bundle:nil];
NSArray *objectArray = [nib instantiateWithOwner:nil options:nil];
CYLView *view = [objectArray firstObject];

App Programming Guide for iOS.

Configuring a View Controller Using Nib Files

• - initWithNibName:bundle:  Designated Initializer
• nibName  Property
  
  The name of the view controller'€™s nib file, if one was specified. (read-only)

Declaration

OBJECTIVE-C

@property(nonatomic, readonly, copy) NSString *nibName

Discussion

This property contains the value specified at initialization time to the initWithNibName:bundle: method. The value of this property may be nil.

If you use a nib file to store your view controller'€™s view, it is recommended that you specify that nib file explicitly when initializing your view controller. However, if you do not specify a nib name, and do not override the loadView method in your custom subclass, the view controller searches for a nib file using other means. Specifically, it looks for a nib file with an appropriate name (without the .nib extension) and loads that nib file whenever its view is requested. Specifically, it looks (in order) for a nib file with one of the following names:

1. If the view controller class name ends with the word ‘Controller’, as in MyViewController, it looks for a nib file whose name matches the class name without the word ‘€œController’, as in MyView.nib.

2. It looks for a nib file whose name matches the name of the view controller class. For example, if the class name is MyViewController, it looks for a MyViewController.nib file.

NOTE

Nib names that include a platform-specific identifier such as ~iphone or ~ipad are loaded only on a device of the corresponding type. For example, a nib name of MyViewController~ipad.nib is loaded only on iPad. If your app supports both platform types, you must provide versions of your nib files for each platform.

Availability

Available in iOS 2.0 and later.

See Also

– initWithNibName:bundle:nibBundle

• nibBundle  Property
• 
  
  
  

Interacting with Storyboards and Segues

• storyboard  Property
• - shouldPerformSegueWithIdentifier:sender:
• - prepareForSegue:sender:
• - performSegueWithIdentifier:sender:
• - allowedChildViewControllersForUnwindingFromSource:
• - childViewControllerContainingSegueSource:
• - canPerformUnwindSegueAction:fromViewController:withSender:
• - unwindForSegue:towardsViewController:
• - viewControllerForUnwindSegueAction:fromViewController:withSender:  (iOS 9.0)
• - segueForUnwindingToViewController:fromViewController:identifier:  (iOS 9.0)
• 
  
  
  

Managing the View

• view  Property
• - isViewLoaded
• - loadView
• - viewDidLoad
• - loadViewIfNeeded
• viewIfLoaded  Property
• title  Property
• preferredContentSize  Property
• 
  
  
  

Presenting View Controllers

• modalPresentationStyle  Property
• modalTransitionStyle  Property
• modalInPopover  Property
• - showViewController:sender:
• - showDetailViewController:sender:
• - presentViewController:animated:completion:
• - dismissViewControllerAnimated:completion:
• definesPresentationContext  Property
• providesPresentationContextTransitionStyle  Property
• - disablesAutomaticKeyboardDismissal
• 
  
  
  

Supporting Custom Transitions and Presentations

• transitioningDelegate  Property
• - transitionCoordinator
• - targetViewControllerForAction:sender:
• presentationController  Property
• popoverPresentationController  Property
• 
  
  
  

Responding to View Events

• - viewWillAppear:
• - viewDidAppear:
• - viewWillDisappear:
• - viewDidDisappear:
• 
  
  
  

Configuring the View’s Layout Behavior

• - viewWillLayoutSubviews
• - viewDidLayoutSubviews
• - updateViewConstraints
• bottomLayoutGuide  Property
• topLayoutGuide  Property
• edgesForExtendedLayout  Property
• extendedLayoutIncludesOpaqueBars  Property
• automaticallyAdjustsScrollViewInsets  Property
• 
  
  
  

Testing for Specific Kinds of View Transitions

• - isMovingFromParentViewController
• - isMovingToParentViewController
• - isBeingPresented
• - isBeingDismissed
• 
  
  
  

Configuring the View Rotation Settings

• - shouldAutorotate
• - supportedInterfaceOrientations
• - preferredInterfaceOrientationForPresentation
• + attemptRotationToDeviceOrientation
• 
  
  
  

Adapting to Environment Changes

• - collapseSecondaryViewController:forSplitViewController:
• - separateSecondaryViewControllerForSplitViewController:
• 
  
  
  

Managing Child View Controllers in a Custom Container

• childViewControllers  Property
• - addChildViewController:
• - removeFromParentViewController
• - transitionFromViewController:toViewController:duration:options:animations:completion:
• - shouldAutomaticallyForwardAppearanceMethods
• - beginAppearanceTransition:animated:
• - endAppearanceTransition
• - setOverrideTraitCollection:forChildViewController:
• - overrideTraitCollectionForChildViewController:
• 
  
  
  

Responding to Containment Events

• - willMoveToParentViewController:
• - didMoveToParentViewController:
• 
  
  
  

Getting Other Related View Controllers

• presentingViewController  Property
• presentedViewController  Property
• parentViewController  Property
• navigationController  Property
• splitViewController  Property
• tabBarController  Property
• 
  
  
  

Handling Memory Warnings

• - didReceiveMemoryWarning
• 
  
  
  

Managing State Restoration

• restorationIdentifier  Property
• restorationClass  Property
• - encodeRestorableStateWithCoder:
• - decodeRestorableStateWithCoder:
• - applicationFinishedRestoringState
• 
  
  
  

Supporting App Extensions

• extensionContext  Property
• 
  
  
  

Working With 3D Touch Previews and Preview Quick Actions

peek and pop. For clarity here, and to align with the API names, this document uses the corresponding terms preview and commit view. To learn more about 3D Touch, read Adopting 3D Touch on iPhone.

• - registerForPreviewingWithDelegate:sourceView:
• - unregisterForPreviewingWithContext:
• - previewActionItems
• 
  
  
  

Managing the Status Bar

• - childViewControllerForStatusBarHidden
• - childViewControllerForStatusBarStyle
• - preferredStatusBarStyle
• - prefersStatusBarHidden
• modalPresentationCapturesStatusBarAppearance  Property
• - preferredStatusBarUpdateAnimation
• - setNeedsStatusBarAppearanceUpdate
• 
  
  
  

Configuring a Navigation Interface

• navigationItem  Property
• hidesBottomBarWhenPushed  Property
• - setToolbarItems:animated:
• toolbarItems  Property
• 
  
  
  

Configuring Tab Bar Items

• tabBarItem  Property
• 
  
  
  

Adding Editing Behaviors to Your View Controller

• editing  Property
• - setEditing:animated:
• - editButtonItem
• 
  
  
  

Accessing the Available Key Commands

• - addKeyCommand:
• - removeKeyCommand:
• 
  
  
  

Managing Banner Ads

• canDisplayBannerAds  Property
• originalContentView  Property
• 
  
  
  

Determining Whether the View Controller is Displaying an Ad

• presentingFullScreenAd  Property
• displayingBannerAd  Property
• 
  
  
  

Managing Interstitial Ads

• + prepareInterstitialAds
• interstitialPresentationPolicy  Property
• - requestInterstitialAdPresentation
• - shouldPresentInterstitialAd
• 
  
  
  

Deprecated

• - viewWillUnload  (iOS 6.0)
• - viewDidUnload  (iOS 6.0)
• contentSizeForViewInPopover  (iOS 7.0)  Property
• - presentModalViewController:animated:  (iOS 6.0)
• - dismissModalViewControllerAnimated:  (iOS 6.0)
• wantsFullScreenLayout  (iOS 7.0)  Property
• - shouldAutorotateToInterfaceOrientation:  (iOS 6.0)
• - rotatingHeaderView  (iOS 8.0)
• - rotatingFooterView  (iOS 8.0)
• interfaceOrientation  (iOS 8.0)  Property
• - willRotateToInterfaceOrientation:duration:  (iOS 8.0)
• - willAnimateRotationToInterfaceOrientation:duration:  (iOS 8.0)
• - didRotateFromInterfaceOrientation:  (iOS 8.0)
• - willAnimateFirstHalfOfRotationToInterfaceOrientation:duration:  (iOS 5.0)
• - didAnimateFirstHalfOfRotationToInterfaceOrientation:  (iOS 5.0)
• - willAnimateSecondHalfOfRotationFromInterfaceOrientation:duration:  (iOS 5.0)
• searchDisplayController  (iOS 8.0)  Property
• modalViewController  (iOS 6.0)  Property
• - shouldAutomaticallyForwardRotationMethods  (iOS 8.0)
• - automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers  (iOS 6.0)
• - presentMoviePlayerViewControllerAnimated:  (iOS 9.0)
• - dismissMoviePlayerViewControllerAnimated  (iOS 9.0)
• 
  
  
  

Constants

• UIModalPresentationStyle
• UIModalTransitionStyle
• ADInterstitialPresentationPolicy
• Exceptions
• 
  
  
  

Notifications

• UIViewControllerShowDetailTargetDidChangeNotification