Animating a pulsing UILabel?
- by fuzzygoat
I am trying to animate the color the the text on a UILabel to pulse from: [Black] to [White] to [Black] and repeat.
- (void)timerFlash:(NSTimer *)timer {
[[self navTitle] setTextColor:[[UIColor whiteColor] colorWithAlphaComponent:0.0]];
[UIView animateWithDuration:1
delay:0
options:UIViewAnimationOptionAllowUserInteraction
animations:^{[[self navTitle] setTextColor:[[UIColor whiteColor] colorWithAlphaComponent:1.0]];}
completion:nil];
}
.
[self setFadeTimer:[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerFlash:) userInfo:nil repeats:YES]];
Firstly I am not sure of my method, my plan (as you can see above) was to set up a animation block and call it using a repeating NSTimer until canceled.
My second problem (as you can see above) is that I am animating from black (alpha 0) to white (alpha 1) but I don't know how to animate back to black again so the animation loops seamlessly
Essentially what I want is the text color to pulse on a UILabel until the user presses a button to continue.
EDIT_001:
I was getting into trouble because you can't animate [UILabel setColor:] you can however animated [UILabel setAlpha:] so I am going to give that a go.
EDIT_002:
- (void)timerFlash:(NSTimer *)timer {
[[self navTitle] setAlpha:0.5];
[UIView animateWithDuration:2
delay:0
options:UIViewAnimationOptionAllowUserInteraction
animations:^{[[self navTitle] setAlpha:0.9];}
completion:nil];
}
This works (BTW: I do want it to stop which is why I hooked it up to a NSTimer so I can cancel that) the only thing is that this animates from midGray to nearWhite and then pops back. Does anyone know how I would animate back from nearWhite to midGray so I get a nice smooth cycle?
EDIT_003: (Solution)
The code suggested by dave DeLong (see below) does indeed work when modified to use the CALayer opacity style attribute:
UILabel *navTitle;
@property(nonatomic, retain) UILabel *navTitle;
.
// ADD ANIMATION
CABasicAnimation *anim = [CABasicAnimation animationWithKeyPath:@"opacity"];
[anim setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];
[anim setFromValue:[NSNumber numberWithFloat:0.5]];
[anim setToValue:[NSNumber numberWithFloat:1.0]];
[anim setAutoreverses:YES];
[anim setDuration:0.5];
[[[self navTitle] layer] addAnimation:anim forKey:@"flash"];
.
// REMOVE ANIMATION
[[[self navTitle] layer] removeAnimationForKey:@"flash__"];
