我不确定一些答案在谈论什么，但我需要把这个答案放在这里，当我下次在谷歌中搜索时。关键词:“如何从一个nib加载一个UIView”或“如何从一个NSBundle加载一个UIView”

下面的代码几乎100%直接来自Apress Beginning iPhone 3的书籍(第247页，“使用新的表视图单元格”):

- (void)viewDidLoad {
    [super viewDidLoad];
    NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:@"Blah"
                                                 owner:self options:nil];
    Blah *blah;
    for (id object in bundle) {
        if ([object isKindOfClass:[Blah class]]) {
            blah = (Blah *)object;
            break;
        }
    }   
    assert(blah != nil && "blah can't be nil");
    [self.view addSubview: blah];
} 

这假设你有一个UIView子类叫Blah，一个nib叫Blah它包含一个UIView它的类设置为Blah。

类别:+ LoadFromNib NSObject

#import "NSObject+LoadFromNib.h"

@implementation NSObject (LoadFromNib)

+ (id)loadFromNib:(NSString *)name classToLoad:(Class)classToLoad {
    NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:name owner:self options:nil];
    for (id object in bundle) {
        if ([object isKindOfClass:classToLoad]) {
            return object;
        }
    }
    return nil;
}

@end

迅速扩展

extension UIView {
    class func loadFromNib<T>(withName nibName: String) -> T? {
        let nib  = UINib.init(nibName: nibName, bundle: nil)
        let nibObjects = nib.instantiate(withOwner: nil, options: nil)
        for object in nibObjects {
            if let result = object as? T {
                return result
            }
        }
        return nil
    }
}

还有一个正在使用的例子:

class SomeView: UIView {
    class func loadFromNib() -> SomeView? {
        return self.loadFromNib(withName: "SomeView")
    }
}

我最终为这个添加了一个类别到UIView:

 #import "UIViewNibLoading.h"

 @implementation UIView (UIViewNibLoading)

 + (id) loadNibNamed:(NSString *) nibName {
    return [UIView loadNibNamed:nibName fromBundle:[NSBundle mainBundle] retainingObjectWithTag:1];
 }

 + (id) loadNibNamed:(NSString *) nibName fromBundle:(NSBundle *) bundle retainingObjectWithTag:(NSUInteger) tag {
    NSArray * nib = [bundle loadNibNamed:nibName owner:nil options:nil];
    if(!nib) return nil;
    UIView * target = nil;
    for(UIView * view in nib) {
        if(view.tag == tag) {
            target = [view retain];
            break;
        }
    }
    if(target && [target respondsToSelector:@selector(viewDidLoad)]) {
        [target performSelector:@selector(viewDidLoad)];
    }
    return [target autorelease];
 }

 @end

这里的解释:在ios和mac中viewcontroller是更少的视图加载

你不应该在Interface Builder中将视图控制器的类设置为UIView的子类。这肯定是你的部分问题。保留它为UIViewController，它的子类，或者其他自定义类。

As for loading only a view from a xib, I was under the assumption that you had to have some sort of view controller (even if it doesn't extend UIViewController, which may be too heavyweight for your needs) set as the File's Owner in Interface Builder if you want to use it to define your interface. I did a little research to confirm this as well. This is because otherwise there would be no way to access any of the interface elements in the UIView, nor would there be a way to have your own methods in code be triggered by events.

If you use a UIViewController as your File's Owner for your views, you can just use initWithNibName:bundle: to load it and get the view controller object back. In IB, make sure you set the view outlet to the view with your interface in the xib. If you use some other type of object as your File's Owner, you'll need to use NSBundle's loadNibNamed:owner:options: method to load the nib, passing an instance of File's Owner to the method. All its properties will be set properly according to the outlets you define in IB.

在Swift 4中以编程方式从nib/xib加载视图:

// Load a view from a Nib given a placeholder view subclass
//      Placeholder is an instance of the view to load.  Placeholder is discarded.
//      If no name is provided, the Nib name is the same as the subclass type name
//
public func loadViewFromNib<T>(placeholder placeholderView: T, name givenNibName: String? = nil) -> T {

    let nib = loadNib(givenNibName, placeholder: placeholderView)
    return instantiateView(fromNib: nib, placeholder: placeholderView)
}

// Step 1: Returns a Nib
//
public func loadNib<T>(_ givenNibName: String? = nil, placeholder placeholderView: T) -> UINib {
    //1. Load and unarchive nib file
    let nibName = givenNibName ?? String(describing: type(of: placeholderView))

    let nib = UINib(nibName: nibName, bundle: Bundle.main)
    return nib
}

// Step 2: Instantiate a view given a nib
//
public func instantiateView<T>(fromNib nib: UINib, placeholder placeholderView: T) -> T {
    //1. Get top level objects
    let topLevelObjects = nib.instantiate(withOwner: placeholderView, options: nil)

    //2. Have at least one top level object
    guard let firstObject = topLevelObjects.first else {
        fatalError("\(#function): no top level objects in nib")
    }

    //3. Return instantiated view, placeholderView is not used
    let instantiatedView = firstObject as! T
    return instantiatedView
}

对于那些需要管理多个自定义视图实例的人，也就是Outlet Collection，我合并并定制了@Gonso， @AVeryDev和@Olie的答案:

Create a custom MyView : UIView and set it as "Custom Class" of the root UIView in the desired XIB; Create all outlets you need in MyView (do it now because after point 3 the IB will propose you to connect outlets to the UIViewController and not to the custom view as we want); Set your UIViewController as "File's Owner" of the custom view XIB; In the UIViewController add a new UIViews for each instance of MyView you want, and connect them to UIViewController creating an Outlet Collection: these views will act as "wrapper" views for the custom view instances; Finally, in the viewDidLoad of your UIViewController add the following lines:

NSArray *bundleObjects; MyView *currView; NSMutableArray *myViews = [NSMutableArray arrayWithCapacity:myWrapperViews.count]; for (UIView *currWrapperView in myWrapperViews) { bundleObjects = [[NSBundle mainBundle] loadNibNamed:@"MyView" owner:self options:nil]; for (id object in bundleObjects) { if ([object isKindOfClass:[MyView class]]){ currView = (MyView *)object; break; } } [currView.myLabel setText:@"myText"]; [currView.myButton setTitle:@"myTitle" forState:UIControlStateNormal]; //... [currWrapperView addSubview:currView]; [myViews addObject:currView]; } //self.myViews = myViews; if need to access them later..

我不确定一些答案在谈论什么，但我需要把这个答案放在这里，当我下次在谷歌中搜索时。关键词:“如何从一个nib加载一个UIView”或“如何从一个NSBundle加载一个UIView”

下面的代码几乎100%直接来自Apress Beginning iPhone 3的书籍(第247页，“使用新的表视图单元格”):

- (void)viewDidLoad {
    [super viewDidLoad];
    NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:@"Blah"
                                                 owner:self options:nil];
    Blah *blah;
    for (id object in bundle) {
        if ([object isKindOfClass:[Blah class]]) {
            blah = (Blah *)object;
            break;
        }
    }   
    assert(blah != nil && "blah can't be nil");
    [self.view addSubview: blah];
} 

这假设你有一个UIView子类叫Blah，一个nib叫Blah它包含一个UIView它的类设置为Blah。

类别:+ LoadFromNib NSObject

#import "NSObject+LoadFromNib.h"

@implementation NSObject (LoadFromNib)

+ (id)loadFromNib:(NSString *)name classToLoad:(Class)classToLoad {
    NSArray *bundle = [[NSBundle mainBundle] loadNibNamed:name owner:self options:nil];
    for (id object in bundle) {
        if ([object isKindOfClass:classToLoad]) {
            return object;
        }
    }
    return nil;
}

@end

迅速扩展

extension UIView {
    class func loadFromNib<T>(withName nibName: String) -> T? {
        let nib  = UINib.init(nibName: nibName, bundle: nil)
        let nibObjects = nib.instantiate(withOwner: nil, options: nil)
        for object in nibObjects {
            if let result = object as? T {
                return result
            }
        }
        return nil
    }
}

还有一个正在使用的例子:

class SomeView: UIView {
    class func loadFromNib() -> SomeView? {
        return self.loadFromNib(withName: "SomeView")
    }
}