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
}

这是一件应该比较容易的事情。我最终扩展了UIViewController并添加了一个loadNib:inPlaceholder: selector。现在我可以说

self.mySubview = (MyView *)[self loadNib:@"MyView" inPlaceholder:mySubview];

下面是这个类别的代码(它和Gonso描述的一样):

@interface UIViewController (nibSubviews)

- (UIView *)viewFromNib:(NSString *)nibName;
- (UIView *)loadNib:(NSString *)nibName inPlaceholder:(UIView *)placeholder;

@end

@implementation UIViewController (nibSubviews)

- (UIView *)viewFromNib:(NSString *)nibName
{
  NSArray *xib = [[NSBundle mainBundle] loadNibNamed:nibName owner:self options:nil]; 
  for (id view in xib) { // have to iterate; index varies
    if ([view isKindOfClass:[UIView class]]) return view;
  }
  return nil;
}

- (UIView *)loadNib:(NSString *)nibName inPlaceholder:(UIView *)placeholder
{
  UIView *nibView = [self viewFromNib:nibName];
  [nibView setFrame:placeholder.frame];
  [self.view insertSubview:nibView aboveSubview:placeholder];
  [placeholder removeFromSuperview];
  return nibView;
}

@end

没有一个答案解释如何创建独立的XIB，这是这个问题的根源。Xcode 4没有“创建新的XIB文件”选项。

要做到这一点

1) Choose "New File..."
2) Choose the "User Interface" category under the iOS section
3) Choose the "View" item
4) You will then be prompted to choose an iPhone or iPad format

这看起来很简单，但它可以为您节省几分钟的时间，因为“XIB”这个词没有出现在任何地方。

我有一种命名xib的约定，其中的视图与视图相同。和视图控制器一样。这样，我就不必在代码中写出类名了。我从同名的nib文件中加载一个UIView。

一个名为MyView的类的例子。

创建一个名为MyView的nib文件。接口生成器中的xib 在Interface Builder中添加一个UIView。将其类设置为MyView。自定义到你的内心的内容，连接MyView的实例变量到子视图，你可能想以后访问。 在你的代码中，像这样创建一个新的MyView: MyView * MyView = [MyView nib_viewfromnibwiowner:owner];

这是它的分类:

@implementation UIView (nib)

+ (id) nib_viewFromNib {
    return [self nib_viewFromNibWithOwner:nil];
}

+ (id) nib_viewFromNibWithOwner:(id)owner {
    NSString *className = NSStringFromClass([self class]);
    NSArray *nib = [[NSBundle mainBundle] loadNibNamed:className owner:owner options:nil];
    UIView *view = nil;
    for(UIView *v in nib) {
        if ([v isKindOfClass:[self class]]) {
            view = v;
            break;
        }
    }
    assert(view != nil && "View for class not found in nib file");
    [view nib_viewDidLoad];
    return view;
}

// override this to do custom setup
-(void)nib_viewDidLoad {

}

然后，我将连接按钮与我正在使用的控制器的动作，并使用自定义视图子类中的outlet在标签上设置内容。

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.

谢谢大家。 我确实找到了做我想做的事的方法。

Create your UIView with the IBOutlets you need. Create the xib in IB, design it to you liking and link it like this: The File's Owner is of class UIViewController (No custom subclass, but the "real" one). The File Owner's view is connected to the main view and its class is declared as the one from step 1). Connect your controls with the IBOutlets. The DynamicViewController can run its logic to decide what view/xib to load. Once its made the decission, in the loadView method put something like this: NSArray* nibViews = [[NSBundle mainBundle] loadNibNamed:@"QPickOneView" owner:self options:nil]; QPickOneView* myView = [ nibViews objectAtIndex: 1]; myView.question = question;

就是这样!

主bundle的loadNibNamed方法将负责初始化视图和创建连接。

现在ViewController可以根据内存中的数据显示一个视图或另一个视图，而“父”屏幕不需要为这个逻辑而烦恼。