UIButton flashing animation

Question

I was wondering if it was possible to apply a flashing animation to a UIButton. I have searched but only found the code for a pulse animation which changes the size of my UIButt

Answer 1

I did this by creating my own control, subclassing UIControl since Apple doesn't recommend screwing with the view hierarchy of UIButton. I add a background imageView representing the standard background image of the button, and a "glowing" imageView above the background to represent the lit-up state, and toggle its opacity to make it pulse.

I additionally toggle the layer's shadow opacity to make it glow.

Initializing Code:

- (void)TS_commonButtonInit
{
    UIImage *shoutoutBackground            = [UIImage imageNamed:@"root-navigation-bar-share-button"];
    UIImage *shoutoutHighlightedBackground = [UIImage imageNamed:@"root-navigation-bar-share-button-highlighted"];
    UIImage *shoutoutPulseImage            = [UIImage imageNamed:@"root-navigation-bar-share-button-glowing"];

    shoutoutBackground            = [shoutoutBackground            stretchableImageWithLeftCapWidth:7 topCapHeight:0];
    shoutoutHighlightedBackground = [shoutoutHighlightedBackground stretchableImageWithLeftCapWidth:7 topCapHeight:0];
    shoutoutPulseImage            = [shoutoutPulseImage            stretchableImageWithLeftCapWidth:7 topCapHeight:0];

    [[self backgroundView] setImage:shoutoutBackground];
    [[self backgroundView] setHighlightedImage:shoutoutHighlightedBackground];

    [self setGlowingImage:shoutoutPulseImage];

    [self setExclusiveTouch:YES];

    [self addSubview:[self backgroundView]];
    [self addSubview:[self glowingImageView]];

    [[self layer] setShadowColor:[[UIColor colorWithHexString:@"ffc521" alpha:1] CGColor]];
    [[self layer] setShadowOpacity:0];
    [[self layer] setShadowRadius:5];
    [[self layer] setShadowOffset:CGSizeMake(0, 0)];
    [[self layer] setShadowPath:[[UIBezierPath bezierPathWithRoundedRect:[self bounds] cornerRadius:6] CGPath]];
}

Pulsing Code:

- (void)pulse:(NSInteger)numberOfTimes
{
    CGFloat pulseLength = .8;

    [[self glowingImageView] setAlpha:0];

    CABasicAnimation *pulseAnimation = [CABasicAnimation animationWithKeyPath:@"opacity"];
    [pulseAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
    [pulseAnimation setDuration:pulseLength];
    [pulseAnimation setRepeatCount:numberOfTimes];
    [pulseAnimation setAutoreverses:YES];
    [pulseAnimation setFromValue:@(0)];
    [pulseAnimation setToValue:@(1)];
    [pulseAnimation setRemovedOnCompletion:YES];

    [[self layer] setShadowOpacity:0];

    CABasicAnimation *shadowAnimation = [CABasicAnimation animationWithKeyPath:@"shadowOpacity"];
    [shadowAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
    [shadowAnimation setDuration:pulseLength];
    [shadowAnimation setRepeatCount:numberOfTimes];
    [shadowAnimation setAutoreverses:YES];
    [shadowAnimation setFromValue:@(0)];
    [shadowAnimation setToValue:@(1)];
    [shadowAnimation setRemovedOnCompletion:YES];

    [[[self glowingImageView] layer] addAnimation:pulseAnimation forKey:@"opacity"];
    [[self layer] addAnimation:shadowAnimation forKey:@"shadowOpacity"];
}