Creating a Pop animation similar to the presentation of UIAlertView - iphone

Question

I would like to present a view in the same manner as that of UIAlertView - a pop/spring. Unfortunately subclassing UIAlertView is not an option for the view I need to present. I have written some code, but I can't seem to get it as realistic as I would like. I would appreciate any suggestions for greater realism or a link if anything similar has been done (I could not find anything on Google). Thank you.
- (id)initWithFrame:(CGRect)frame {
if ((self = [super initWithFrame:frame])) {
self.backgroundColor = [UIColor whiteColor];
v = [[UIView alloc] initWithFrame:CGRectMake(140, 140, 60, 60)];
v.backgroundColor = [UIColor blueColor];
[self addSubview:v];
[self animate];
}
return self;
}
- (void)animate {
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
[UIView setAnimationDuration:0.2];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:#selector(popStep1Complete)];
v.frame = CGRectMake(90, 90, 140, 140);
[UIView commitAnimations];
}
- (void)popStep1Complete {
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
[UIView setAnimationDuration:0.15];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:#selector(popStep2Complete)];
v.frame = CGRectMake(110, 110, 100, 100);
[UIView commitAnimations];
}
- (void)popStep2Complete {
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationCurve:UIViewAnimationCurveLinear];
[UIView setAnimationDuration:0.15];
v.frame = CGRectMake(100, 100, 120, 120);
[UIView commitAnimations];
}

Answer 1

- (void) attachPopUpAnimation
{
CAKeyframeAnimation *animation = [CAKeyframeAnimation
animationWithKeyPath:#"transform"];
CATransform3D scale1 = CATransform3DMakeScale(0.5, 0.5, 1);
CATransform3D scale2 = CATransform3DMakeScale(1.2, 1.2, 1);
CATransform3D scale3 = CATransform3DMakeScale(0.9, 0.9, 1);
CATransform3D scale4 = CATransform3DMakeScale(1.0, 1.0, 1);
NSArray *frameValues = [NSArray arrayWithObjects:
[NSValue valueWithCATransform3D:scale1],
[NSValue valueWithCATransform3D:scale2],
[NSValue valueWithCATransform3D:scale3],
[NSValue valueWithCATransform3D:scale4],
nil];
[animation setValues:frameValues];
NSArray *frameTimes = [NSArray arrayWithObjects:
[NSNumber numberWithFloat:0.0],
[NSNumber numberWithFloat:0.5],
[NSNumber numberWithFloat:0.9],
[NSNumber numberWithFloat:1.0],
nil];
[animation setKeyTimes:frameTimes];
animation.fillMode = kCAFillModeForwards;
animation.removedOnCompletion = NO;
animation.duration = .2;
[self.layer addAnimation:animation forKey:#"popup"];
}

Answer 2

the pointer to delackner's post is the best initial one i found as well. i would only offer for folks trying to really mimic UIAlertView a few things:
adding the rounded edges, border, and semi-transparent layer color
some alpha fade-in/-out, and
redoing with blocks as somewhat more succinct with latest iOS toolchain
i also found the initial 1.1 scale-out he suggests too large, 1.05 seemed more correct visually to me in most cases
Code:
self.layer.cornerRadius = 10.0;
[self.layer setMasksToBounds:YES];
self.layer.backgroundColor = [[UIColor blueColor] colorWithAlphaComponent:0.60].CGColor;
self.layer.borderColor = [UIColor whiteColor].CGColor;
self.layer.borderWidth = 1.1;
if (self.hidden == YES) { // swoop in if coming from hidden, otherwise pulse in-place
self.transform = CGAffineTransformMakeScale(0.6, 0.6);
}
self.hidden = NO;
[UIView animateWithDuration:0.2
animations:^{
self.transform = CGAffineTransformMakeScale(1.05, 1.05);
self.alpha = 0.8;
}
completion:^(BOOL finished){
[UIView animateWithDuration:1/15.0
animations:^{
self.transform = CGAffineTransformMakeScale(0.9, 0.9);
self.alpha = 0.9;
}
completion:^(BOOL finished) {
[UIView animateWithDuration:1/7.5
animations:^{
self.transform = CGAffineTransformIdentity;
self.alpha = 1.0;
}
];
}
];
}
];

Answer 3

One thing: multi-step animations like this are much easier if you use a CAKeyframeAnimation instead of mutiple UIView queued animations.