如何在Swift中使用NSTimer？

本文介绍了如何在Swift中使用NSTimer？的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我试过

var timer = NSTimer() timer(timeInterval: 0.01, target: self, selector: update, userInfo: nil, repeats: false)

但是，我收到错误说

'(timeInterval: $T1, target: ViewController, selector: () -> (), userInfo: NilType, repeats: Bool) -> $T6' is not identical to 'NSTimer'

推荐答案

这将工作：

override func viewDidLoad() { super.viewDidLoad() // Swift block syntax (iOS 10+) let timer = Timer(timeInterval: 0.4, repeats: true) { _ in print("Done!") } // Swift >=3 selector syntax let timer = Timer.scheduledTimer(timeInterval: 0.4, target: self, selector: #selector(self.update), userInfo: nil, repeats: true) // Swift 2.2 selector syntax let timer = NSTimer.scheduledTimerWithTimeInterval(0.4, target: self, selector: #selector(MyClass.update), userInfo: nil, repeats: true) // Swift <2.2 selector syntax let timer = NSTimer.scheduledTimerWithTimeInterval(0.4, target: self, selector: "update", userInfo: nil, repeats: true) } // must be internal or public. @objc func update() { // Something cool }

对于Swift 4，您希望获取选择器的方法必须暴露给Objective-C，因此必须将 @objc 属性添加到方法声明中。

For Swift 4, the method of which you want to get the selector must be exposed to Objective-C, thus @objc attribute must be added to the method declaration.