我有一个名为MyClass 的类，它是UIView 的子类，我想用XIB 文件对其进行初始化。我不确定如何使用名为 View.xib 的 xib 文件初始化此类
class MyClass: UIView {
// what should I do here?
//init(coder aDecoder: NSCoder) {} ??
}
【问题讨论】：
我测试了这段代码，效果很好：
class MyClass: UIView {
class func instanceFromNib() -> UIView {
return UINib(nibName: "nib file name", bundle: nil).instantiateWithOwner(nil, options: nil)[0] as UIView
}
}
初始化视图并像下面这样使用它：
var view = MyClass.instanceFromNib()
self.view.addSubview(view)
或
var view = MyClass.instanceFromNib
self.view.addSubview(view())
更新 Swift >=3.x & Swift >=4.x
class func instanceFromNib() -> UIView {
return UINib(nibName: "nib file name", bundle: nil).instantiate(withOwner: nil, options: nil)[0] as! UIView
}
【讨论】：
var view = MyClass.instanceFromNib() & self.view.addSubview(view) 而不是 var view = MyClass.instanceFromNib & self.view.addSubview(view())。只是一个改善答案的小建议:)
Sam 的解决方案已经很棒了，尽管它没有考虑不同的包（NSBundle:forClass 来拯救）并且需要手动加载，也就是输入代码。
如果您想全面支持您的 Xib Outlets、不同的捆绑包（在框架中使用！）并在 Storyboard 中获得不错的预览，请尝试以下操作：
// NibLoadingView.swift
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 weak var view: UIView!
override init(frame: CGRect) {
super.init(frame: frame)
nibSetup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
nibSetup()
}
private func nibSetup() {
backgroundColor = .clearColor()
view = loadViewFromNib()
view.frame = bounds
view.autoresizingMask = [.FlexibleWidth, .FlexibleHeight]
view.translatesAutoresizingMaskIntoConstraints = true
addSubview(view)
}
private func loadViewFromNib() -> UIView {
let bundle = NSBundle(forClass: self.dynamicType)
let nib = UINib(nibName: String(self.dynamicType), bundle: bundle)
let nibView = nib.instantiateWithOwner(self, options: nil).first as! UIView
return nibView
}
}
像往常一样使用您的 xib，即将 Outlets 连接到 File Owner 并将 File Owner 类设置为您自己的类。
用法：只需从 NibLoadingView 子类化您自己的 View 类并在 Xib 文件中将类名设置为 File's Owner
不再需要额外的代码。
信用到期的信用：与 GH 上的 DenHeadless 进行了细微的更改。我的要点：https://gist.github.com/winkelsdorf/16c481f274134718946328b6e2c9a4d8
【讨论】：
NibLoadingView 嵌入 XIB 中，从 init?(coder:) 调用 nibSetup 将导致无限递归。
.clearColor() - 从情节提要加载后。但是，如果在实例化后通过代码执行此操作，它应该可以工作。无论如何，如前所述，一种更优雅的方法是基于协议的方法。当然，这里有一个链接：github.com/AliSoftware/Reusable。我现在正在对 UITableViewCells 使用类似的方法（我在发现那个真正有用的项目之前就实现了它）。 hth！
从 Swift 2.0 开始，您可以添加协议扩展。在我看来，这是一种更好的方法，因为返回类型是Self 而不是UIView，因此调用者不需要强制转换为视图类。
import UIKit
protocol UIViewLoading {}
extension UIView : UIViewLoading {}
extension UIViewLoading where Self : UIView {
// note that this method returns an instance of type `Self`, rather than UIView
static func loadFromNib() -> Self {
let nibName = "\(self)".characters.split{$0 == "."}.map(String.init).last!
let nib = UINib(nibName: nibName, bundle: nil)
return nib.instantiateWithOwner(self, options: nil).first as! Self
}
}
【讨论】：
var myView = nib.instantiate... as! myViewType
let nibName = String(describing: Self.self) (Swift 3) 获取类的名称
这是 Frederik 在 Swift 3.0 上的回答
/*
Usage:
- make your CustomeView class and inherit from this one
- in your Xib file make the file owner is your CustomeView class
- *Important* the root view in your Xib file must be of type UIView
- link all outlets to the file owner
*/
@IBDesignable
class NibLoadingView: UIView {
@IBOutlet weak var view: UIView!
override init(frame: CGRect) {
super.init(frame: frame)
nibSetup()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
nibSetup()
}
private func nibSetup() {
backgroundColor = .clear
view = loadViewFromNib()
view.frame = bounds
view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
view.translatesAutoresizingMaskIntoConstraints = true
addSubview(view)
}
private func loadViewFromNib() -> UIView {
let bundle = Bundle(for: type(of: self))
let nib = UINib(nibName: String(describing: type(of: self)), bundle: bundle)
let nibView = nib.instantiate(withOwner: self, options: nil).first as! UIView
return nibView
}
}
【讨论】：
从 xib 加载视图的通用方式：
例子：
let myView = Bundle.loadView(fromNib: "MyView", withType: MyView.self)
实施：
extension Bundle {
static func loadView<T>(fromNib name: String, withType type: T.Type) -> T {
if let view = Bundle.main.loadNibNamed(name, owner: nil, options: nil)?.first as? T {
return view
}
fatalError("Could not load view with type " + String(describing: type))
}
}
【讨论】：
斯威夫特 4
在我的例子中，我必须将数据传递到该自定义视图中，因此我创建了静态函数来实例化视图。
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
}
}
创建我的自定义视图
class MyCustomView: UIView {
@IBOutlet weak var messageLabel: UILabel!
static func instantiate(message: String) -> MyCustomView {
let view: MyCustomView = initFromNib()
view.messageLabel.text = message
return view
}
}
实例化视图
let view = MyCustomView.instantiate(message: "Hello World.")
【讨论】：
Swift 3 答案：就我而言，我想在我的自定义类中有一个可以修改的插座：
class MyClassView: UIView {
@IBOutlet weak var myLabel: UILabel!
class func createMyClassView() -> MyClassView {
let myClassNib = UINib(nibName: "MyClass", bundle: nil)
return myClassNib.instantiate(withOwner: nil, options: nil)[0] as! MyClassView
}
}
在 .xib 文件中时，确保自定义类字段是 MyClassView。不要打扰文件的所有者。
另外，请确保将 MyClassView 中的插座连接到标签：
实例化它：
let myClassView = MyClassView.createMyClassView()
myClassView.myLabel.text = "Hello World!"
【讨论】：
Swift 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。
您现在可以像 ExampleView()、ExampleView(frame: CGRect) 等一样或直接从情节提要中初始化类。
您也可以像在UIViewController 中一样使用viewDidLoad。在那一刻呈现您所有的插座和布局。
【讨论】：
如果有人想以编程方式使用 XIB 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)
【讨论】：
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)
})
})
}
【讨论】：