CABasicAnimation how to get current angle of rotation - ios

Question

I have some problem with CABasicAnimation. It`s similar to that post: CABasicAnimation rotate returns to original position
So, i have uiimageview that rotate in touchMove. In touchEnd invoke method that do "animation of inertia" :
-(void)animationRotation: (float)beginValue
{
CABasicAnimation *anim;
anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation"];
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
anim.duration = 0.5;
anim.repeatCount = 1;
anim.fillMode = kCAFillModeForwards;
anim.fromValue = [NSNumber numberWithFloat:beginValue];
[anim setDelegate:self];
anim.toValue = [NSNumber numberWithFloat:(360*M_PI/180 + beginValue)];
[appleView.layer addAnimation:anim forKey:#"transform"];
CGAffineTransform rot = CGAffineTransformMakeRotation(360*M_PI/180 + beginValue);
appleView.transform = rot;
}
This animation works fine, but if I invoke touchBegan before animationRotation ended, angle of rotation is beginValue. I need cath current angle of rotation. As an experiment, i declare method
-(vod) animationDidStop:(CAAnimation *)anim finished:(BOOL)flag
{
NSLog(#"Animation finished!");
}
and it's seems working. but I don't know how get that value of angle or CGAffineTransform for my UIImageView in animationDidStop.
It's even possible to do? Thanks.

Answer 1

you should use presentationLayer method to get layer properties during animation in flight.
so your code should be like this,
#define RADIANS_TO_DEGREES(__ANGLE__) ((__ANGLE__) / (float)M_PI * 180.0f)
-(void)animationRotation: (float)beginValue
{
CABasicAnimation *anim;
anim = [CABasicAnimation animationWithKeyPath:#"transform.rotation.z"];
anim.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
anim.duration = 0.5;
anim.repeatCount = 1;
anim.fillMode = kCAFillModeForwards;
anim.fromValue = [NSNumber numberWithFloat:beginValue];
[anim setDelegate:self];
//get current layer angle during animation in flight
CALayer *currentLayer = (CALayer *)[appleView.layer presentationLayer];
float currentAngle = [(NSNumber *)[currentLayer valueForKeyPath:#"transform.rotation.z"] floatValue];
currentAngle = roundf(RADIANS_TO_DEGREES(currentAngle));
NSLog(#"current angle: %f",currentAngle);
anim.toValue = [NSNumber numberWithFloat:(360*M_PI/180 + beginValue)];
[appleView.layer addAnimation:anim forKey:#"transform"];
CGAffineTransform rot = CGAffineTransformMakeRotation(360*M_PI/180 + beginValue);
appleView.transform = rot;
}