Question

以下是代码：

import Cocoa
import Foundation

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {

    @IBOutlet weak var window: NSWindow!


    func applicationDidFinishLaunching(_ aNotification: Notification) {
        // Insert code here to initialize your application
        lbl.drawsBackground = true
        lbl.backgroundColor = NSColor.black
        Timer.scheduledTimer(withTimeInterval: 1.0/Double(hz * 2), repeats: true, block: toggleBackground)
    }

    var hz = 40

    func toggleBackground(_ timer: Timer) {
        if lbl.backgroundColor == NSColor.white{
            lbl.backgroundColor = NSColor.black
        } else {
            lbl.backgroundColor = NSColor.white
        }
    }

    func applicationWillTerminate(_ aNotification: Notification) {
        // Insert code here to tear down your application
    }


    @IBOutlet weak var lbl: NSTextField!
}

此处的完整项目：https://github.com/kindlychung/Flickalz

这是一个简单的应用程序，可以在80Hz下更改标签的背景颜色。我想在运行时使频率可以自定义（通过文本字段或滑块），但不知道如何完成。有什么想法吗？

Answer 1

诀窍是使计时器无效并重新计算：

import Cocoa
import Foundation

@NSApplicationMain
class AppDelegate: NSObject, NSApplicationDelegate {

    @IBOutlet weak var window: NSWindow!

    @IBOutlet weak var freqFld: NSTextField!

    @IBAction func setFreq(_ sender: NSButton) {
        restartTimer(freqFld.integerValue)
    }


    func applicationDidFinishLaunching(_ aNotification: Notification) {
        // Insert code here to initialize your application
        window.backgroundColor = NSColor.black
    }

    var timer: Timer = Timer()

    func restartTimer(_ hz: Int) {
        timer.invalidate()
        timer = Timer.scheduledTimer(withTimeInterval: 1.0/Double(hz * 2), repeats: true, block: toggleBackground)
    }

    override init() {
        super.init()
        restartTimer(40)
    }

    func toggleBackground(_ timer: Timer) {
        if window.backgroundColor == NSColor.white{
            window.backgroundColor = NSColor.black
        } else {
            window.backgroundColor = NSColor.white
        }
    }

    func applicationWillTerminate(_ aNotification: Notification) {
        // Insert code here to tear down your application
    }


}

可在此处找到完整项目：https://github.com/kindlychung/Flickalz

Answer 2

您可以尝试将UISlider放入第一个UIViewController。

然后，请按照本教程：http://sourcefreeze.com/ios-slider-uislider-example-using-swift/

在运行时更改调度程序的时间间隔

2 个答案: