Blinking effect on UILabel

Question

I have a UILabel with background color as grey.

I want a blinking effect on this label like it should become a little white & then become gray and it should keep happen till I turn it off programatically.

Any clue how to achieve this?

Answer 1

You can simply make an extension to the UILabel class that will support the blinking effect. I don't think using a timer is a right approach since you won't have any fade effect.

Here is the Swift way to do this:

extension UILabel {
    func blink() {
        self.alpha = 0.0;
        UIView.animateWithDuration(0.8, //Time duration you want,
                            delay: 0.0,
                          options: [.CurveEaseInOut, .Autoreverse, .Repeat],
                       animations: { [weak self] in self?.alpha = 1.0 },
                       completion: { [weak self] _ in self?.alpha = 0.0 })
    }
}

Swift 3:

extension UILabel {
    func blink() {
        self.alpha = 0.0;
        UIView.animate(withDuration: 0.8, //Time duration you want,
            delay: 0.0,
            options: [.curveEaseInOut, .autoreverse, .repeat],
            animations: { [weak self] in self?.alpha = 1.0 },
            completion: { [weak self] _ in self?.alpha = 0.0 })
    }
}

EDIT Swift 3: Works for almost any view

extension UIView {
    func blink() {
        self.alpha = 0.0;
        UIView.animate(withDuration: 0.8, //Time duration you want,
            delay: 0.0,
            options: [.curveEaseInOut, .autoreverse, .repeat],
            animations: { [weak self] in self?.alpha = 1.0 },
            completion: { [weak self] _ in self?.alpha = 0.0 })
    }
}

Answer 2

-(void) startBlinkingLabel:(UILabel *)label 
{
    label.alpha =1.0f;
    [UIView animateWithDuration:0.32
                          delay:0.0
                        options: UIViewAnimationOptionAutoreverse |UIViewAnimationOptionRepeat | UIViewAnimationOptionCurveEaseInOut | UIViewAnimationOptionAllowUserInteraction |UIViewAnimationOptionBeginFromCurrentState
                     animations:^{
                         label.alpha = 0.0f;
                     }
                     completion:^(BOOL finished){
                         if (finished) {

                         }
                     }];
}

-(void) stopBlinkingLabel:(UILabel *)label 
{
    // REMOVE ANIMATION
    [label.layer removeAnimationForKey:@"opacity"];
    label.alpha = 1.0f;
}

Answer 3

Rather use the view animations. It makes it very simple and is easy to control. Try this:

self.yourLabel.alpha = 1.0f;
[UIView animateWithDuration:0.12
  delay:0.0
  options:UIViewAnimationOptionCurveEaseInOut | 
          UIViewAnimationOptionRepeat | 
          UIViewAnimationOptionAutoreverse | 
          UIViewAnimationOptionAllowUserInteraction
  animations:^{
   self.yourLabel.alpha = 0.0f;
}
completion:^(BOOL finished){
// Do nothing
}];

You can tweak the values to get different effects for example, changing animateWithDuration wil set the blinking speed. Further you can use it on anything that inherits from UIView example a button, label, custom view etc.

Answer 4

You can do this within a block:

self.yourLabel.alpha = 1;
[UIView animateWithDuration:1.5 delay:0.5 options:UIViewAnimationOptionRepeat | UIViewAnimationOptionAutoreverse animations:^{
        self.yourLabel.alpha = 0;
} completion:nil];

So you dont need a second method.

Answer 5

Swift 3

extension UILabel {

    func startBlink() {
        UIView.animate(withDuration: 0.8,
              delay:0.0,
              options:[.allowUserInteraction, .curveEaseInOut, .autoreverse, .repeat],
              animations: { self.alpha = 0 }, 
              completion: nil)
    }

    func stopBlink() {
        layer.removeAllAnimations()
        alpha = 1
    }
}

Answer 6

My swift version based on Flex Elektro Deimling's answer:

private func startTimeBlinkAnimation(start: Bool) {
    if start {
        timeContainerView.alpha = 1
        UIView.animateWithDuration(0.6, delay: 0.3, options:[.Repeat, .Autoreverse], animations: { _ in
            self.timeContainerView.alpha = 0
        }, completion: nil)
    }
    else {
        timeContainerView.alpha = 1
        timeContainerView.layer.removeAllAnimations()
    }
}