Core Animation - animationDidStop not called - ios

Question

there.
in iOS app, Core animation callback don't work.
- (void)startAnim {
CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
anim.fromValue = startAngle;
anim.toValue = endAngle;
anim.duration = 2;
anim.delegate = self;
[self.target addAnimation:anim forKey:nil]; // self.target is CALayer instance, it's sublayer of Custom UIView
}
- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag {
[self.target setValue:#(endAngle) forKeyPath:#"transform.rotation.z"];
}
But animationDidStop never be called.
If I change the code like as following, completion blocked is called.
- (void)startAnim {
CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
anim.fromValue = startAngle;
anim.toValue = endAngle;
anim.duration = 2;
anim.delegate = self;
[CATransaction begin];
[CATransaction setCompletionBlock:^{
[self.target setValue:#(endAngle) forKeyPath:#"transform.rotation.z"];
}];
[self.target addAnimation:anim forKey:nil];
[CATransaction commit];
}
But I don't want to use CATransaction.
Why is not animationDidStop called?
Update:
There is a way to set final value like as
- (void)startAnim {
CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
anim.fromValue = startAngle;
anim.toValue = endAngle;
anim.duration = 2;
anim.delegate = self;
[self.target setValue:#(endAngle) forKeyPath:#"transform.rotation.z"];
[self.target addAnimation:anim forKey:nil];
}
But final assignment should be done when the animation is finished. Because there are multiple dynamic animations of layer, so I don't know final value.

Answer 1

I found the reason why animationDidStop is not called.
Because animation was added in loop of other thread,
So I fixed like as following.
- (void)startAnim {
dispatch_async(dispatch_get_main_queue(), ^{
CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
anim.fromValue = startAngle;
anim.toValue = endAngle;
anim.duration = 2;
anim.delegate = self;
[self.target addAnimation:anim forKey:nil];
});
}

Answer 2

To me it sounds like you dont want the animation to reset its position, this is quite simple and achieved with a couple lines of code when setting up the animation.
It can be easily placed in your code like such:
anim.fillMode = kCAFillModeForwards;
anim.removedOnCompletion = NO;
What this means is when your animation has finished it will remain at the end and any further animations will be from that state.

Answer 3

Last year I use animation of UIView instead CABasicAnimation, but if my memory does not fail you have to set endAngle befor add animation, so try this:
- (void)startAnim {
CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
anim.fromValue = startAngle;
anim.toValue = endAngle;
anim.duration = 2;
anim.delegate = self;
[self.target setValue:#(endAngle) forKeyPath:#"transform.rotation.z"];
[self.target addAnimation:anim forKey:nil];
}
UPD:
You are setting anim.toValue = endAngle; before start animation, so its not good that end value changes after animation complete. Anyway you can set it again in animationDidStop
- (void)startAnim {
CABasicAnimation* anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
anim.fromValue = startAngle;
anim.toValue = endAngle;
anim.duration = 2;
anim.delegate = self;
intermediateAngle = endAngle;
[self.target setValue:#(endAngle) forKeyPath:#"transform.rotation.z"];
[self.target addAnimation:anim forKey:nil];
}
- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag {
if (intermediateAngle != endAngle) {
startAngle = intermediateAngle;
[self startAnim]; // or just [self.target setValue:#(endAngle) forKeyPath:#"transform.rotation.z"];
}
}