Question

I didnt found any solution on the internet so I decided to ask my question here. There is this cool animation effect you can make with a buttton that if you tap it it jumps and lands like a pop. If you know what I mean. I simply mean that the button bounces like a rubberbal if you hit the floor once. I saw this effect on many different gaming apps and would like to do this in my app. It is actually like making the button bigger and immediatly smaller if it was tapped. Does anybody know how to do this?

Thanks in advance.

Answer 1

Check this blog which describes about bounce effect on icon. That should guide you to right direction. Also check this lantean blog and this cocoanetics blog.

This is the code he is using,

+ (CAKeyframeAnimation*)dockBounceAnimationWithViewHeight:(CGFloat)viewHeight
{
    NSUInteger const kNumFactors    = 22;
    CGFloat const kFactorsPerSec    = 30.0f;
    CGFloat const kFactorsMaxValue  = 128.0f;
    CGFloat factors[kNumFactors]    = {0,  60, 83, 100, 114, 124, 128, 128, 124, 114, 100, 83, 60, 32, 0, 0, 18, 28, 32, 28, 18, 0};

    NSMutableArray* transforms = [NSMutableArray array];

    for(NSUInteger i = 0; i < kNumFactors; i++)
    {
        CGFloat positionOffset  = factors[i] / kFactorsMaxValue * viewHeight;
        CATransform3D transform = CATransform3DMakeTranslation(0.0f, -positionOffset, 0.0f);

        [transforms addObject:[NSValue valueWithCATransform3D:transform]];
    }

    CAKeyframeAnimation* animation = [CAKeyframeAnimation animationWithKeyPath:@"transform"];
    animation.repeatCount           = 1;
    animation.duration              = kNumFactors * 1.0f/kFactorsPerSec;
    animation.fillMode              = kCAFillModeForwards;
    animation.values                = transforms;
    animation.removedOnCompletion   = YES; // final stage is equal to starting stage
    animation.autoreverses          = NO;

    return animation;
}

- (void)bounce:(float)bounceFactor
{
    CGFloat midHeight = self.frame.size.height * bounceFactor;
    CAKeyframeAnimation* animation = [[self class] dockBounceAnimationWithViewHeight:midHeight];
    [self.layer addAnimation:animation forKey:@"bouncing"];
}