EXC_BAD_ACCESS while using CoreAnimation

问题:

I use CoreAnimation to animate UIImageView (curve Bezier animation). Here`s my code:

CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
pathAnimation.calculationMode = kCAAnimationCubic;
pathAnimation.fillMode = kCAFillModeForwards;
pathAnimation.removedOnCompletion = NO;

CGPoint endPoint = originalPosition;

UIBezierPath *path = [UIBezierPath bezierPath];
[path moveToPoint:star.layer.position];
[path addQuadCurveToPoint:endPoint controlPoint:CGPointMake(star.layer.position.x, endPoint.y)];

pathAnimation.path = path.CGPath;

[star.layer addAnimation:pathAnimation forKey:@"moveToScorebarAnimation"];

As a result, I get EXC_BAD_ACCESS (code=2, address=0x0) with stacktrace:

CoreGraphics`CG::Path::apply(void*, void (*)(void*, CGPathElementType, CGPoint const*)) const:
0x613c06:  pushl  %ebp
0x613c07:  movl   %esp, %ebp
0x613c09:  subl   $24, %esp
0x613c0c:  movl   8(%ebp), %eax
0x613c0f:  movl   (%eax), %ecx
0x613c11:  movl   (%ecx), %eax
0x613c13:  movl   16(%ebp), %edx
0x613c16:  movl   %edx, 8(%esp)
0x613c1a:  movl   12(%ebp), %edx
0x613c1d:  movl   %edx, 4(%esp)
0x613c21:  movl   %ecx, (%esp)
0x613c24:  calll  *64(%eax)
0x613c27:  addl   $24, %esp
0x613c2a:  popl   %ebp
0x613c2b:  ret  

I tried to use different manuals to do it, but app crashes the same way. Can't understand where`s my fault. Any help will be appreciated, thanks.

P. S. Here's a similar bug, but unfortunately it is solved just by removing animation.

P. P. S. Arc is enabled. Also, if I comment pathAnimation.path = path.CGPath; line, crash does not appear, as well as animation (what is not surprised :) ).

回答1:

That error will be thrown when the object doesn't exist in memory. Make sure you initialization is proper way ?? make sure you initialize Layer..etc.. ?

Best way is use BreakPoint to find out where your application get crush ??

I'm not sure but it may be helpful for you.

Add your animation as

CAAnimationGroup *group = [CAAnimationGroup animation];
group.animations = [NSArray arrayWithObjects: pathAnimation,nil];
group.duration = 7.0;  //The total time of the animations, don't know if redundant
group.delegate = self;

[self.layer addAnimation:group forKey:@"path"];

回答2:

Replace CAKeyframeAnimation with CABasicAnimation:

 CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"position"];
 pathAnimation.fromValue = [NSValue valueWithCGPoint:star.layer.position];
 pathAnimation.toValue = [NSValue valueWithCGPoint:endPoint];
 pathAnimation.fillMode = kCAFillModeForwards;
 pathAnimation.removedOnCompletion = NO;

Seems it's Apple bug