Add gradient animation

gistfile1.m

- (void)addGradientAnimation
{
    UIColor *color1 = [UIColor redColor];
    UIColor *color2 = [UIColor yellowColor];
    UIColor *color3 = [UIColor grayColor];
    
    CAGradientLayer *gradient = [CAGradientLayer layer];
    gradient.frame = self.view.frame;
    gradient.colors = @[(id)color1.CGColor, (id)color2.CGColor, (id)color2.CGColor];
    
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"colors"];
    animation.toValue = @[(id)color3.CGColor, (id)color1.CGColor, (id)color1.CGColor];
    animation.duration = 3.0;
    animation.autoreverses = YES;
    animation.repeatCount = HUGE_VALF;
    
    [gradient addAnimation:animation forKey:@"colors"];
    
    [self.view.layer addSublayer:gradient];
}