如何用 Swift 中的 XIB 文件初始化/实例化自定义 UIView 类

override func draw(_ rect: CGRect)
{
AlertView.layer.cornerRadius = 4
AlertView.clipsToBounds = true


btnOk.layer.cornerRadius = 4
btnOk.clipsToBounds = true
}


class func instanceFromNib() -> LAAlertView {
return UINib(nibName: "LAAlertView", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! LAAlertView
}


@IBAction func okBtnDidClicked(_ sender: Any) {


removeAlertViewFromWindow()


UIView.animate(withDuration: 0.4, delay: 0.0, options: .allowAnimatedContent, animations: {() -> Void in
self.AlertView.transform = CGAffineTransform(scaleX: 0.1, y: 0.1)


}, completion: {(finished: Bool) -> Void in
self.AlertView.transform = CGAffineTransform.identity
self.AlertView.transform = CGAffineTransform(scaleX: 0.0, y: 0.0)
self.AlertView.isHidden = true
self.AlertView.alpha = 0.0


self.alpha = 0.5
})
}




func removeAlertViewFromWindow()
{
for subview  in (appDel.window?.subviews)! {
if subview.tag == 500500{
subview.removeFromSuperview()
}
}
}




public func openAlertView(title:String , string : String ){


lblTital.text  = title
txtView.text  = string


self.frame = CGRect(x: 0, y: 0, width: screenWidth, height: screenHeight)
appDel.window!.addSubview(self)




AlertView.alpha = 1.0
AlertView.isHidden = false


UIView.animate(withDuration: 0.2, animations: {() -> Void in
self.alpha = 1.0
})
AlertView.transform = CGAffineTransform(scaleX: 0.0, y: 0.0)


UIView.animate(withDuration: 0.3, delay: 0.2, options: .allowAnimatedContent, animations: {() -> Void in
self.AlertView.transform = CGAffineTransform(scaleX: 1.1, y: 1.1)


}, completion: {(finished: Bool) -> Void in
UIView.animate(withDuration: 0.2, animations: {() -> Void in
self.AlertView.transform = CGAffineTransform(scaleX: 1.0, y: 1.0)


})
})




}

Swift 4

在我的例子中，我必须将数据传递到自定义视图中，因此我创建静态函数来实例化视图。

1. 创建 UIView 扩展

   extension UIView {
   class func initFromNib<T: UIView>() -> T {
   return Bundle.main.loadNibNamed(String(describing: self), owner: nil, options: nil)?[0] as! T
   }
   }
   

2. Create MyCustomView

   class MyCustomView: UIView {
   
   
   @IBOutlet weak var messageLabel: UILabel!
   
   
   static func instantiate(message: String) -> MyCustomView {
   let view: MyCustomView = initFromNib()
   view.messageLabel.text = message
   return view
   }
   }
   

3. Set custom class to MyCustomView in .xib file. Connect outlet if necessary as usual.

4. Instantiate view

   let view = MyCustomView.instantiate(message: "Hello World.")
   

如果有人想用 XIB 以编程方式加载自定义视图，下面的代码将完成这项工作。

let customView = UINib(nibName:"CustomView",bundle:.main).instantiate(withOwner: nil, options: nil).first as! UIView
customView.frame = self.view.bounds
self.view.addSubview(customView)

斯威夫特5.3

创建一个名为 NibLoadingView的类，其内容如下:

import UIKit


/* Usage:
- Subclass your UIView from NibLoadView to automatically load an Xib with the same name as your class
- Set the class name to File's Owner in the Xib file
*/


@IBDesignable
class NibLoadingView: UIView {


@IBOutlet public weak var view: UIView!
    

private var didLoad: Bool = false


public override init(frame: CGRect) {
super.init(frame: frame)
        

self.nibSetup()
}


required public init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
        

self.nibSetup()
}
    

open override func layoutSubviews() {
super.layoutSubviews()
        

if !self.didLoad {
self.didLoad = true
self.viewDidLoad()
}
}
    

open func viewDidLoad() {
self.setupUI()
}


private func nibSetup() {
self.view = self.loadViewFromNib()
self.view.frame = bounds
self.view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
self.view.translatesAutoresizingMaskIntoConstraints = true


addSubview(self.view)
}


private func loadViewFromNib() -> UIView {
guard let nibName = type(of: self).description().components(separatedBy: ".").last else {
fatalError("Bad nib name")
}
        

if let defaultBundleView = UINib(nibName: nibName, bundle: Bundle(for: type(of: self))).instantiate(withOwner: self, options: nil).first as? UIView {
return defaultBundleView
} else {
fatalError("Cannot load view from bundle")
}
}
}

现在创建一个 XIB 和 UIView 类对，将 XIB 的所有者设置为 UIView 类和子类 NibLoadingView。

你现在可以像 ExampleView()、 ExampleView(frame: CGRect)等等一样初始化这个类，或者直接从故事板中进行初始化。

你也可以像在 UIViewController中一样使用 viewDidLoad。你所有的插座和布局都是在那一刻呈现的。

^{基于 弗雷德里克的回答}

从.xib 创建视图

let nib = UINib(nibName: "View1", bundle: nil) //View1 is a file name(View1.swift)
if let view = nib.instantiate(withOwner: self, options: nil).first as? UIView {
// logic
}


//or


if let view = Bundle.main.loadNibNamed("View1", owner: self, options: nil)?.first as? UIView {
// logic
}

因为. xib 可以包含多个视图，这就是为什么要在这里使用 array (.first)

比如说

1. 创建 View1.xib
2. 在代码中创建 View1.ift，其中 set owner (loadNibNamed())用于创建 class ("View1")的实例
3. 将 View1.xib中的 File's Owner设置为 View1。允许连接插座和操作

import UIKit


class View1: UIView {
@IBOutlet var contentView: UIView!
    

override init(frame: CGRect) {
super.init(frame: frame)
self.commonInit()
}


required init?(coder: NSCoder) {
super.init(coder: coder)
self.commonInit()
}
    

private func commonInit() {
if let view = Bundle.main.loadNibNamed("View1", owner: self, options: nil)?.first as? UIView {
addSubview(view)
view.frame = self.bounds
}
}
}

笔记 如果我们把 Custom Class从 File's owner移动到 Container View，我们会得到错误(循环) ，这是因为:

从 Container View初始化系统实例，在 commonInit()中再次初始化

.loadNibNamed

Thread 1: EXC_BAD_ACCESS (code=2, address=0x7ff7bf6fbfc8)