Animate UILabel with progress percentage swift

Question

I am trying to animate a UILabel to go from 0% to (insert number)%, and show each number in between in a duration of 1 second..

I have failed until now and I am going crazy :-)

I haven't even made it to the part where I can set the duration yet.. What I have done so far (and failed at) is this:

        var current: Int = Int(0.0 * 100)
        let endValue: Int = Int(toValue * 100)


        if current < endValue {


            self.progressLabel.text = "\(current)%"

            current += Int(0.01 * 100)
        }

The toValue is a Double that it is receiving when the function is called. Any help would be great!

EDIT: I made it show the correct endValue in the uilabel using this code instead and moving var current... up before the viewDidLoad. The problem is now that it is not showing the numbers in between the current and the endValue in the progressLabel.text..

while current <= endValue {
            self.progressLabel.text = "\(current)%"
            current = current + Int(0.01 * 100)
        }

Have u place a debug point to check that your `current` is updated with correct value? — Zac Kwan, Oct 24 '16 at 15:33
Are you sure the function is being called? What part is not working exactly? — TheValyreanGroup, Oct 24 '16 at 15:35
@ZacKwan I added print(current) after the current should be updated. The only thing I got was a 1.. That is not even the `endValue`? — FeReTu, Oct 24 '16 at 15:41
That explain why it didn't get updated, because it is only call once. Can you show how the function is called? — Zac Kwan, Oct 24 '16 at 15:43
Hard to tell without seeing more, but it looks like you reset current each time it is called as well. — CodeBender, Oct 24 '16 at 15:45
@ZacKwan I have edited the question with a better working code but not exactly what I am looking for. — FeReTu, Oct 24 '16 at 15:49

CodeBender · Answer 1 · 2016-10-24T23:24:21.207

Here is a function that does not rely on timers, instead using the DispatchQueue asyncAfter method from GCD.

func updateCounter(currentValue: Int, toValue: Double) {
        if currentValue <= Int(toValue * 100) {
            progressLabel.text = "\(currentValue)%"
            let dispatchTime: DispatchTime = DispatchTime.now() + Double(Int64(1.0 * Double(NSEC_PER_SEC))) / Double(NSEC_PER_SEC)
            DispatchQueue.main.asyncAfter(deadline: dispatchTime, execute: {
                self.updateCounter(currentValue: currentValue + 1, toValue: toValue)
            })
        }
    }

Calling it with this will produce a count from 0-10:

updateCounter(currentValue: 0, toValue: 0.1)

score 0 · Answer 2 · edited May 23 '17 at 12:33

The problem you have now in your recently updated code is that your program will not update the UILabel every time current is changed. The while loop will continue until current reaches is final value, then your UILabel will be updated once.

What would probably help you is using timers, as referenced in this answer:

How to make a countdown with NSTimer on Swift

Make a method that increments the UILabel's current value by one, then use the timer to call that method once every second.

Animate UILabel with progress percentage swift

2 Answers2