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具有可选属性的UIView扩展

swift-extensions uiview swift

0

Rawr · 技术社区 · 7 年前

这是我现在的代码:

@objc protocol BaseView {
  @objc optional var header: UILabel { get set }
  @objc optional var footer: UILabel { get set }
}

class ViewWithHeader: UIView, BaseView {
  @IBOutlet var header: UILabel!
}

class ViewWithFooter: UIView, BaseView {
  @IBOutlet var footer: UILabel!
}


var view: BaseView!
if (header != nil) {
  view = Bundle.main.loadNibNamed("ViewWithHeader", owner: self, option: nil)?.first as! ViewWithHeader
} else if (footer != nill) {
  view = Bundle.main.loadNibNamed("ViewWithFooter", owner: self, option: nil)?.first as! ViewWithFooter
}

view.header?.text = "Header"
view.footer?.text = "Footer"
view.alpha // This line fails because BaseView has no member 'alpha'

我的问题是如何扩展UIView以包括可选的 header 和 footer 变量?也许我做得完全错了,在这种情况下,我希望有一个指向正确方向的指针。

1 回复 | 直到 7 年前

1

Malik 7 年前

如果我正确理解你的问题,你需要 BaseView 的一个子类 UIView

class BaseView: UIView {
    var header: UILabel?
    var footer: UILabel?
}

编辑

class BaseView: UIView {
    @IBOutlet var header: UILabel?
    @IBOutlet var footer: UILabel?
}

class ViewWithHeader: BaseView {
}

class ViewWithFooter: BaseView {
}


var view: BaseView!
if (header != nil) {
  view = Bundle.main.loadNibNamed("ViewWithHeader", owner: self, option: nil)?.first as! ViewWithHeader
} else if (footer != nil) {
  view = Bundle.main.loadNibNamed("ViewWithFooter", owner: self, option: nil)?.first as! ViewWithFooter
}

view.header?.text = "Header"
view.footer?.text = "Footer"
view.alpha // This line fails because BaseView has no member 'alpha'