使用 NSTimer 快速查看进度

Question

我有一个进度 View 栏，我想用它来指示时间。这是我在 Swift 中的第一个项目，我不确定如何去做。所以任何帮助/建议将不胜感激......

(使用 Xcode 7.2 和 Swift 2.0)

下面是我的 View Controller 。触发“btnPlaySession”时， View Controller 上的内容每 20 秒更改一次。当计时器计数到 20 时，我喜欢用进度条来指示这一点(因此进度条会重置，每次内容更改时)。

class CreatedSessionViewController: UIViewController {

var createdSession: [YogaPose]!
var poseDuration: Double = 20.00 
var timer = NSTimer!()
var currentPoseIndex = 1

//Outlets:
@IBOutlet var poseProgressView: UIProgressView!
@IBOutlet var lblPoseCount: UILabel!
@IBOutlet var lblPoseName: UILabel!
@IBOutlet var imgPose: UIImageView!
@IBOutlet var tvDescription: UITextView!

// Do any additional setup after loading the view:
override func viewDidLoad() {
    super.viewDidLoad()

    displayFirstPoseInArray()
}

func displayFirstPoseInArray(){
    lblPoseCount.text = (String(currentPoseIndex) + "/" + String(createdSession.count))
    lblPoseName.text = createdSession[0].title
    imgPose.image = UIImage(named: String(format: "%d.jpg", (createdSession[0].id)!))
    tvDescription.text = createdSession[0].desc
}

@IBAction func btnPlaySession(sender: AnyObject) {
    timer = NSTimer.scheduledTimerWithTimeInterval(poseDuration, target: self, selector: "getNextPoseData", userInfo: nil, repeats: true)
}

func getNextPoseData(){
    if (currentPoseIndex < createdSession.count){

        setProgressBar()

        lblPoseCount.text = (String(currentPoseIndex + 1) + "/" + String(createdSession.count))
        lblPoseName.text = createdSession[currentPoseIndex].title
        imgPose.image = UIImage(named: String(format: "%d.jpg",(createdSession[currentPoseIndex].id)!))
        tvDescription.text = createdSession[currentPoseIndex].desc
        currentPoseIndex += 1
        print(currentPoseIndex)
    }
}

func setProgressBar(){


}
}

Answer 1

好的 - 所以如果你想让进度条每秒更新一次，那么你需要一个每秒触发的计时器 - 但它会触发 20 次，并调用 setProgressBar 作为选择器而不是 getNextPoseData

在 setProgressBar 中，您需要增加一个类级别的属性，indexProgressBar 可能，并且只需将进度条属性 progress 设置为 1.0/索引进度条

如果 indexProgressBar == 20，则调用 getNextPoseData，并重置进度条

这里是你如何做的一个简化版本

class ViewController: UIViewController
{
    @IBOutlet weak var progressBar: UIProgressView!
    var timer = NSTimer!()
    var poseDuration = 20
    var indexProgressBar = 0
    var currentPoseIndex = 0

    override func viewDidLoad()
    {
        super.viewDidLoad()

        // initialise the display
        progressBar.progress = 0.0
    }


    @IBAction func cmdGo(sender: AnyObject)
    {
        // display the first pose
        getNextPoseData()

        // start the timer
        timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: "setProgressBar", userInfo: nil, repeats: true)
    }

    func getNextPoseData()
    {
        // do next pose stuff
        currentPoseIndex += 1
        print(currentPoseIndex)
    }

    func setProgressBar()
    {
        if indexProgressBar == poseDuration
        {
            getNextPoseData()

            // reset the progress counter
            indexProgressBar = 0
        }

        // update the display
        // use poseDuration - 1 so that you display 20 steps of the the progress bar, from 0...19
        progressBar.progress = Float(indexProgressBar) / Float(poseDuration - 1)

        // increment the counter
        indexProgressBar += 1
    }
}