如何在
Swift中将字符串属性与UIButton相关联？我不希望字符串显示为按钮文本,只是将其指定为按钮作为标识符或键.这是我到目前为止：
func createAnswerButtons() {
var index:Int
for index = 0; index < self.currentQuestion?.answers.count; index++ {
// Create an answer button view
var answer:AnswerButtonView = AnswerButtonView()
selection.setTranslatesAutoresizingMaskIntoConstraints(false)
// Place into content view
self.scrollViewContentView.addSubview(answer)
// Add a tapped gesture recognizer to the button
let tapGesture:UITapGestureRecognizer = UITapGestureRecognizer(target: self,action: Selector("answerTapped:"))
answer.addGestureRecognizer(tapGesture)
// Add constraints etc
// Set the answer button text
let answerText = self.currentQuestion!.answers[index]
answer.setAnswerText(answerText)
// Set the identifier for each answer button
self.identifier = self.currentQuestion!.answerIdentifier[index]
// Add to the selection button array
self.answerButtonArray.append(answer)
}
所以我想我需要一些东西
// Set the identifier for each answer
self.identifier = self.currentQuestion!.answerIdentifier[index]
将标识符分配给按钮.
这样做的原因是我正在尝试实现一个决策树逻辑,这样我就可以跟踪每个被点击的答案按钮,以生成一个与最终结果相对应的代码字符串.
解决方法
使用Objective-C运行时,我们可以在运行时向类添加属性：
extension UIButton {
private struct AssociatedKeys {
static var DescriptiveName = "nsh_DescriptiveName"
}
@IBInspectable var descriptiveName: String? {
get {
return objc_getAssociatedObject(self,&AssociatedKeys.DescriptiveName) as? String
}
set {
if let newValue = newValue {
objc_setAssociatedObject(
self,&AssociatedKeys.DescriptiveName,newValue as NSString?,UInt(OBJC_ASSOCIATION_RETAIN_NONATOMIC)
)
}
}
}
}
添加@IBInspectable还允许我们通过Interface Builder设置descriptiveName属性.
有关Objective-C运行时的更多信息,我建议您查看this NSHipster article.
