Swift-创建进度条

Question

Hi I am using this code to try and animate a progress bar based on time.

  import UIKit

class LoadingScreen: UIViewController {

    @IBOutlet var progressView: UIProgressView!

    override func viewDidLoad() {
        super.viewDidLoad()



        var time = 0.0
        var timer: NSTimer

        timer = NSTimer.scheduledTimerWithTimeInterval(0.1, target: self, selector:Selector("setProgress"), userInfo: nil, repeats: true)

        func setProgress() {
            time += 0.1
                progressView.progress = time / 3
            if time >= 3 {
                timer.invalidate()
            }
        }

However I get an error which says: cannot sign a value of type double to a value of type float.

EDIT:

The error is on this line:

progressView.progress = time / 3 

Answer 1

Unless told otherwise swift compiler assumes type inference of Double for 0.0 - declare as

var time : Float = 0.0

Reference - https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/TheBasics.html - Swift always chooses Double (rather than Float) when inferring the type of floating-point numbers.