我根据这段代码创建了一个类:https://gist.github.com/etartakovsky/06b8c9894458a3ff1b14
当我尝试实例化类并调用 tick 方法时,出现“无法识别的选择器已发送到实例”错误。我一遍又一遍地检查了代码,但不明白为什么会这样,欢迎任何建议:
秒表类来源:
import Foundation
import QuartzCore
class StopWatch: NSObject{
private var displayLink: CADisplayLink!
private let formatter = DateFormatter()
var callback: (() -> Void)?
var elapsedTime: CFTimeInterval!
override init() {
super.init()
self.displayLink = CADisplayLink(target: self, selector: "tick:")
displayLink.isPaused = true
displayLink.add(to: RunLoop.main, forMode: RunLoopMode.commonModes)
self.elapsedTime = 0.0
formatter.dateFormat = "mm:ss,SS"
}
convenience init(withCallback callback: @escaping () -> Void) {
self.init()
self.callback = callback
}
deinit {
displayLink.invalidate()
}
func tick(sender: CADisplayLink) {
elapsedTime = elapsedTime + displayLink.duration
callback?()
}
func start() {
displayLink.isPaused = false
}
func stop() {
displayLink.isPaused = true
}
func reset() {
displayLink.isPaused = true
elapsedTime = 0.0
callback?()
}
func elapsedTimeAsString() -> String {
return formatter.string(from: Date(timeIntervalSinceReferenceDate:elapsedTime))
}
}
这是 ViewController 代码:
import UIKit
class ActivityViewController: UIViewController {
let stopwatch = StopWatch()
@IBOutlet weak var elapsedTimeLabel: UILabel!
func tick() {
elapsedTimeLabel.text = stopwatch.elapsedTimeAsString()
}
override func viewDidLoad() {
super.viewDidLoad()
tick()
stopwatch.callback = self.tick
stopwatch.start()
// Do any additional setup after loading the view.
}
}
最佳答案
在 Swift 3 中使用 #selector
语法
self.displayLink = CADisplayLink(target: self, selector: #selector(tick))
在 Swift 4 中,你还必须在操作的开头插入 @objc
@objc func tick(...
关于ios - 无法识别的选择器发送到实例 - Swift 3,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47237270/