How to animate incrementing number in UILabel

Question

I have a label showing a number and I want to change it to a higher number, however I'd like to add a bit of flare to it. I'd like to have the number increment up to the higher number with an ease inout curve so it speeds up then slows down. This answer shows how to make it increment (the 2nd answer, not the accepted answer) but I'd rather animate it so I could also make it increase in size slightly then shrink again as well as the ease inout curve. how to do a running score animation in iphone sdk

Any ideas how best to achieve this? Thanks

The start/end numbers will be user inputted and I want it to increment up the the end number in the same amount of time. So if I have start 10 end 100 or start 10 end 1000 I want it to count up to the end number in say 5 seconds.

Answer 1

I actually made such a class just for this called UICountingLabel:

http://github.com/dataxpress/UICountingLabel

It allows you to specify whether you want the counting mode to be linear, ease in, ease out, or ease in/out. Ease in/out starts counting slowly, speeds up, and then finishes slowly - all in whatever amount of time you specify.

It doesn't currently support setting the actual font size of the label based on the current value, though I may add support for that if it's a feature that's in-demand. Most of the labels in my layouts don't have a lot of room to grow or shrink, so I'm not sure how you want to use it. However, it behaves totally like a normal label, so you can change the font size on your own as well.

Answer 2

Here @malex's answer in swift 3.

func incrementLabel(to endValue: Int) {
    let duration: Double = 2.0 //seconds
    DispatchQueue.global().async {
        for i in 0 ..< (endValue + 1) {
            let sleepTime = UInt32(duration/Double(endValue) * 1000000.0)
            usleep(sleepTime)
            DispatchQueue.main.async {
                self.myLabel.text = "\(i)"
            }
        }
    }
}

However, I strongly recommend simply downloading this class from GitHub and dragging it into your project, I've resorted to using it because the timing in my code doesn't seem to adjust properly for lower/higher count numbers. This class works great and looks very good. See this medium article for reference.

Answer 3

You can use GCD to shift delays to background threads.

Here is the example of value animation (from 1 to 100 in 10 seconds)

float animationPeriod = 10;
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), ^{
    for (int i = 1; i < 101; i ++) {
        usleep(animationPeriod/100 * 1000000); // sleep in microseconds
        dispatch_async(dispatch_get_main_queue(), ^{
            yourLabel.text = [NSString stringWithFormat:@"%d", i];
        });
    }
});