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我想通过学习教程(link)和来了解MVVM模式我无法获得我添加到UIButton中的操作来工作(I'使用Swift 3.0)。我已经尝试了几个小时的调试,研究了这个线程(@selector in swift)和其他人,而且我仍然陷入困境。当我点击按钮时,根本没有任何反应。我用选择器尝试了各种语法选项,我认为你在下面看到的是正确的。我认为我使用的协议可能会导致问题,但鉴于我对协议的有限经验,我可能完全错误。在UIButton上的操作不起作用
我会把所有的代码放在这里,以防有人想把它放到Xcode中。这里所讨论的行动是在我UIViewController
,我添加到showGreetingButton
:
class GreetingViewController : UIViewController {
let showGreetingButton = UIButton()
@IBOutlet weak var greetingLabel: UILabel!
var viewModel: GreetingViewModelProtocol! {
didSet {
self.viewModel.greetingDidChange = { [unowned self] viewModel in
self.greetingLabel.text = viewModel.greeting
}
}
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func viewDidLoad() {
super.viewDidLoad()
showGreetingButton.backgroundColor = UIColor.red
showGreetingButton.tintColor = UIColor.black
showGreetingButton.setTitle("Show Greeting", for: .normal)
// I add the action here:
showGreetingButton.addTarget(self.viewModel, action: #selector(GreetingViewModel.showGreeting), for: .touchUpInside)
showGreetingButton.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(showGreetingButton)
let buttonTop = NSLayoutConstraint(item: showGreetingButton, attribute: NSLayoutAttribute.top, relatedBy: NSLayoutRelation.greaterThanOrEqual, toItem: view, attribute: NSLayoutAttribute.topMargin, multiplier: 1.0, constant: 20)
let buttonLeading = NSLayoutConstraint(item: showGreetingButton, attribute: NSLayoutAttribute.leading, relatedBy: NSLayoutRelation.equal, toItem: view, attribute: NSLayoutAttribute.leadingMargin, multiplier: 1.0, constant: 0.0)
showGreetingButton.contentEdgeInsets = UIEdgeInsetsMake(2, 2, 2, 2)
NSLayoutConstraint.activate([buttonTop, buttonLeading])
let model = Person(firstName: "David", lastName: "Blaine")
let viewModel = GreetingViewModel(person: model)
self.viewModel = viewModel
}
}
我的视图模型被称为GreetingViewModel其采用的协议:
protocol GreetingViewModelProtocol: class {
var greeting: String? { get }
var greetingDidChange: ((GreetingViewModelProtocol) ->())? { get set }
init(person: Person)
func showGreeting()
}
class GreetingViewModel : GreetingViewModelProtocol {
let person: Person
var greeting: String? {
didSet {
self.greetingDidChange?(self)
}
}
var greetingDidChange: ((GreetingViewModelProtocol) ->())?
required init(person: Person) {
self.person = person
}
@objc func showGreeting() {
self.greeting = "Hello" + " " + self.person.firstName + " " + self.person.lastName
}
}
我的简单模式是:
struct Person {
let firstName: String
let lastName: String
}
任何帮助将真的,真的很感激。
我也不得不搬到'让模型=人(名字:“大卫”,姓氏:“布莱恩”)与这两行,但它的工作!谢谢! – Jim
@Vinodh,@ beyoulf的回答在你编辑它之前是更好的,因为它明确表示重要的是这些行在showGreetingButton.addTarget(self.viewModel,action:#selector(GreetingViewModel.showGreeting)之前,用于: .touchUpInside)'。你的编辑不太清楚。 – Jim
将替换旧的 – Vinodh