Swift 为什么无法强制转换类型为';UIView&x27;换个角度看?
这个问题涉及的代码与我前面的问题相同Swift 为什么无法强制转换类型为';UIView&x27;换个角度看?,swift,uiview,casting,Swift,Uiview,Casting,这个问题涉及的代码与我前面的问题相同 (上一个问题是) 但是完全不同的方法 这不是重复的问题 因此,让我重新构造我的问题 首先,让我总结一下我的项目 由于前面的回答,我现在可以重用xib了。 这是CardContentView.xib 代码如下 @IBDesignable class CardContentView: UIView { @IBOutlet weak var backgroundView: UIView! @IBInspectable var nibName:
(上一个问题是)
但是完全不同的方法
这不是重复的问题
因此,让我重新构造我的问题
首先,让我总结一下我的项目 由于前面的回答,我现在可以重用xib了。 这是CardContentView.xib 代码如下
@IBDesignable class CardContentView: UIView {
@IBOutlet weak var backgroundView: UIView!
@IBInspectable var nibName:String?
var contentView: UIView?
override func awakeFromNib() {
super.awakeFromNib()
xibSetup()
}
override func prepareForInterfaceBuilder() {
super.prepareForInterfaceBuilder()
xibSetup()
contentView?.prepareForInterfaceBuilder()
}
func xibSetup(){
guard let view = loadViewFromNib() else { return }
view.frame = self.bounds
view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
addSubview(view)
contentView = view
}
func loadViewFromNib() -> UIView? {
guard let nibName = nibName else { return nil }
let bundle = Bundle(for: type(of: self))
let nib = UINib(nibName: nibName, bundle: bundle)
return nib.instantiate(withOwner: self, options: nil).first as? UIView
}
}
class CardView: UIView {
@IBOutlet weak var cardContentView: CardContentView!
override func awakeFromNib() {
cardContentView.layer.cornerRadius = 16
}
}
class ViewController: UIViewController {
@IBOutlet weak var cardView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
}
}
这是cardwiew.xib,属性位于“class CardContentView”之后
代码如下
@IBDesignable class CardContentView: UIView {
@IBOutlet weak var backgroundView: UIView!
@IBInspectable var nibName:String?
var contentView: UIView?
override func awakeFromNib() {
super.awakeFromNib()
xibSetup()
}
override func prepareForInterfaceBuilder() {
super.prepareForInterfaceBuilder()
xibSetup()
contentView?.prepareForInterfaceBuilder()
}
func xibSetup(){
guard let view = loadViewFromNib() else { return }
view.frame = self.bounds
view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
addSubview(view)
contentView = view
}
func loadViewFromNib() -> UIView? {
guard let nibName = nibName else { return nil }
let bundle = Bundle(for: type(of: self))
let nib = UINib(nibName: nibName, bundle: bundle)
return nib.instantiate(withOwner: self, options: nil).first as? UIView
}
}
class CardView: UIView {
@IBOutlet weak var cardContentView: CardContentView!
override func awakeFromNib() {
cardContentView.layer.cornerRadius = 16
}
}
class ViewController: UIViewController {
@IBOutlet weak var cardView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
}
}
这是主故事板。只有一个视图。
代码如下
@IBDesignable class CardContentView: UIView {
@IBOutlet weak var backgroundView: UIView!
@IBInspectable var nibName:String?
var contentView: UIView?
override func awakeFromNib() {
super.awakeFromNib()
xibSetup()
}
override func prepareForInterfaceBuilder() {
super.prepareForInterfaceBuilder()
xibSetup()
contentView?.prepareForInterfaceBuilder()
}
func xibSetup(){
guard let view = loadViewFromNib() else { return }
view.frame = self.bounds
view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
addSubview(view)
contentView = view
}
func loadViewFromNib() -> UIView? {
guard let nibName = nibName else { return nil }
let bundle = Bundle(for: type(of: self))
let nib = UINib(nibName: nibName, bundle: bundle)
return nib.instantiate(withOwner: self, options: nil).first as? UIView
}
}
class CardView: UIView {
@IBOutlet weak var cardContentView: CardContentView!
override func awakeFromNib() {
cardContentView.layer.cornerRadius = 16
}
}
class ViewController: UIViewController {
@IBOutlet weak var cardView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
}
}
但是,我想在ViewController中将类“CardView”重用为“CardView”属性我想将'background'属性改为'cardwiew'属性(简单地说,我想在CardContentView中将黄色框改为蓝色框!)
我想使“cardView”属性具有过渡效果
但是,我无法进行扩展,因为它不在UIView类中,而是在ViewController类中
所以我需要制作另一个UIView类
这就是为什么我单独制作了一个CardView类
(当然,我希望通过创建另一个文件来整齐地组织代码。) 所以,我尝试了两种不同的方法
class ViewController: UIViewController {
@IBOutlet weak var cardView: CardView!
override func viewDidLoad() {
super.viewDidLoad()
}
}
override func viewDidLoad() {
super.viewDidLoad()
let tappedView = self.cardView as! CardView
self.view.addSubview(tappedView)
}
1.当我制作“@ibvar-cardwiew:cardwiew!”时,它抛出错误消息,“在展开可选值cardContentView=nil时意外发现nil”
2.当我制作“let tappedView=self.cardView as!”!CardView'会引发错误消息,“无法将类型为'UIView'(0x10a229ff8)的值强制转换为'awakefromnibtuitorial.CardView'(0x1060aa8d0)。” 我怎样才能解决这个问题
请帮帮我
- 在CardView类的
中,您没有调用awakeFromNib()
super.awakeFromNib()
- 您必须使用与从其相应的XIB加载CardContentView相同的逻辑(
),才能从其XIB加载CardView李>xibSetup()
- 在故事板的ViewController中,您是否已将UIView的类指定给CardView