ios - 在 CAKeyframeAnimation 中崩溃，用于沿路径对 View 进行动画处理

Question

我有一些代码可以为 UIView 设置动画:在沿路径设置动画的同时将其缩小。

它因以下错误而崩溃(可重现:总是):

CoreGraphics`CG::Path::apply(void*, void (*)(void*, CGPathElementType, CGPoint const*)) const:
0x1055c06:  pushl  %ebp
0x1055c07:  movl   %esp, %ebp
0x1055c09:  subl   $24, %esp
0x1055c0c:  movl   8(%ebp), %eax
0x1055c0f:  movl   (%eax), %ecx
0x1055c11:  movl   (%ecx), %eax
0x1055c13:  movl   16(%ebp), %edx
0x1055c16:  movl   %edx, 8(%esp)
0x1055c1a:  movl   12(%ebp), %edx
0x1055c1d:  movl   %edx, 4(%esp)
0x1055c21:  movl   %ecx, (%esp)
0x1055c24:  calll  *64(%eax)
0x1055c27:  addl   $24, %esp
0x1055c2a:  popl   %ebp
0x1055c2b:  ret    

我认为它来自下面的方法(pathAnimationWithStartPoint:)，好像我没有添加它返回的 CAKeyframeAnimation，即，只是:

[group setAnimations:@[ zoomAnimation ]];

代替

[group setAnimations:@[ zoomAnimation, pathAnimation ]];

它运行时不会崩溃。

- (CAKeyframeAnimation *) pathAnimationWithStartPoint:(CGPoint) startPoint {
    CGPoint endPoint = self.showApplicationTourButton.center;

    CGFloat xDistanceBetweenStartAndEndPoints = abs(startPoint.x - endPoint.x);
    CGFloat yOfHighestPointOfCurvePath = endPoint.y - 250;

    CGPoint controlPoint1 =  CGPointMake(startPoint.x + 1.0f / 3.0f * xDistanceBetweenStartAndEndPoints, yOfHighestPointOfCurvePath);
    CGPoint controlPoint2 = CGPointMake(startPoint.x + 2.0f / 3.0f * xDistanceBetweenStartAndEndPoints, yOfHighestPointOfCurvePath);

    CGMutablePathRef curvedPath = CGPathCreateMutable();

    CGPathMoveToPoint(curvedPath, NULL, startPoint.x, startPoint.y);
    CGPathAddCurveToPoint(curvedPath, NULL, controlPoint1.x, controlPoint1.y, controlPoint2.x, controlPoint2.y, endPoint.x, endPoint.y);


    CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"];
    pathAnimation.path = curvedPath;
    CGPathRelease(curvedPath);



    pathAnimation.calculationMode = kCAAnimationPaced;
    pathAnimation.fillMode = kCAFillModeForwards;
    pathAnimation.removedOnCompletion = NO;


    return pathAnimation;
}

回溯:

* thread #1: tid = 0x1a03, 0x01055c11 CoreGraphics`CG::Path::apply(void*, void (*)(void*, CGPathElementType, CGPoint const*)) const + 11, stop reason = EXC_BAD_ACCESS (code=2, address=0x0)
    frame #0: 0x01055c11 CoreGraphics`CG::Path::apply(void*, void (*)(void*, CGPathElementType, CGPoint const*)) const + 11
    frame #1: 0x00f5d090 CoreGraphics`CGPathApply + 64
    frame #2: 0x01838c68 QuartzCore`CA::Render::Path::new_path(CGPath const*, bool) + 158
    frame #3: 0x018c3493 QuartzCore`-[CAKeyframeAnimation _setCARenderAnimation:layer:] + 176
    frame #4: 0x018c3b2c QuartzCore`-[CAKeyframeAnimation _copyRenderAnimationForLayer:] + 68
    frame #5: 0x018c6f12 QuartzCore`-[CAAnimationGroup _copyRenderAnimationForLayer:] + 241
    frame #6: 0x018df547 QuartzCore`CA::Layer::commit_animations(CA::Transaction*, double (*)(CA::Layer*, double, void*), void (*)(CA::Layer*, CA::Render::Animation*, void*), void (*)(CA::Layer*, void**, void*), void*) + 641
    frame #7: 0x01855520 QuartzCore`CA::Context::commit_layer(CA::Layer*, unsigned int, unsigned int, void*) + 94
    frame #8: 0x018d87fa QuartzCore`CA::Layer::commit_if_needed(CA::Transaction*, void (*)(CA::Layer*, unsigned int, unsigned int, void*), void*) + 330
    frame #9: 0x018d877e QuartzCore`CA::Layer::commit_if_needed(CA::Transaction*, void (*)(CA::Layer*, unsigned int, unsigned int, void*), void*) + 206
    frame #10: 0x01856667 QuartzCore`CA::Context::commit_transaction(CA::Transaction*) + 1775
    frame #11: 0x01857227 QuartzCore`CA::Transaction::commit() + 395
    frame #12: 0x018f9b17 QuartzCore`+[CATransaction commit] + 52
    frame #13: 0x000399bf MyApp`-[HomeViewController catchTourScrollViewScreenshotViewAndAnimateItToButton](self=0x0b4e5210, _cmd=0x006f381a) + 1903 at HomeViewController.m:197
    frame #14: 0x0391f663 libobjc.A.dylib`-[NSObject performSelector:] + 62
    frame #15: 0x0003c383 MyApp`-[NSObject(self=0x0b4e5210, _cmd=0x006ef5ad, selector=0x006f381a) performSelectorIfRespondsToIt:] + 243 at NSObject+PerformSelectorIfRespondsToIt.m:22
    frame #16: 0x00042506 MyApp`__44-[TourViewController closeTourWithAnimation]_block_invoke268(.block_descriptor=0x0b6985a0, finished='\x01') + 86 at TourViewController.m:419
    frame #17: 0x01af0df6 UIKit`-[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 223
    frame #18: 0x01ae3d66 UIKit`-[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 237
    frame #19: 0x01ae3f04 UIKit`-[UIViewAnimationState animationDidStop:finished:] + 68
    frame #20: 0x12b6ff28 UIKit`-[UIViewAnimationStateAccessibility(SafeCategory) animationDidStop:finished:] + 66
    frame #21: 0x018df7d8 QuartzCore`CA::Layer::run_animation_callbacks(void*) + 284
    frame #22: 0x03a90014 libdispatch.dylib`_dispatch_client_callout + 14
    frame #23: 0x03a807d5 libdispatch.dylib`_dispatch_main_queue_callback_4CF + 296
    frame #24: 0x03f3eaf5 CoreFoundation`__CFRunLoopRun + 1925
    frame #25: 0x03f3df44 CoreFoundation`CFRunLoopRunSpecific + 276
    frame #26: 0x03f3de1b CoreFoundation`CFRunLoopRunInMode + 123
    frame #27: 0x044c67e3 GraphicsServices`GSEventRunModal + 88
    frame #28: 0x044c6668 GraphicsServices`GSEventRun + 104
    frame #29: 0x01aa5ffc UIKit`UIApplicationMain + 1211
    frame #30: 0x0000285d MyApp`main(argc=1, argv=0xbffff3f4) + 141 at main.m:16
    frame #31: 0x00002785 MyApp`start + 53
* thread #1: tid = 0x1a03, 0x01055c11 CoreGraphics`CG::Path::apply(void*, void (*)(void*, CGPathElementType, CGPoint const*)) const + 11, stop reason = EXC_BAD_ACCESS (code=2, address=0x0)
    frame #0: 0x01055c11 CoreGraphics`CG::Path::apply(void*, void (*)(void*, CGPathElementType, CGPoint const*)) const + 11
    frame #1: 0x00f5d090 CoreGraphics`CGPathApply + 64
    frame #2: 0x01838c68 QuartzCore`CA::Render::Path::new_path(CGPath const*, bool) + 158
    frame #3: 0x018c3493 QuartzCore`-[CAKeyframeAnimation _setCARenderAnimation:layer:] + 176
    frame #4: 0x018c3b2c QuartzCore`-[CAKeyframeAnimation _copyRenderAnimationForLayer:] + 68
    frame #5: 0x018c6f12 QuartzCore`-[CAAnimationGroup _copyRenderAnimationForLayer:] + 241
    frame #6: 0x018df547 QuartzCore`CA::Layer::commit_animations(CA::Transaction*, double (*)(CA::Layer*, double, void*), void (*)(CA::Layer*, CA::Render::Animation*, void*), void (*)(CA::Layer*, void**, void*), void*) + 641
    frame #7: 0x01855520 QuartzCore`CA::Context::commit_layer(CA::Layer*, unsigned int, unsigned int, void*) + 94
    frame #8: 0x018d87fa QuartzCore`CA::Layer::commit_if_needed(CA::Transaction*, void (*)(CA::Layer*, unsigned int, unsigned int, void*), void*) + 330
    frame #9: 0x018d877e QuartzCore`CA::Layer::commit_if_needed(CA::Transaction*, void (*)(CA::Layer*, unsigned int, unsigned int, void*), void*) + 206
    frame #10: 0x01856667 QuartzCore`CA::Context::commit_transaction(CA::Transaction*) + 1775
    frame #11: 0x01857227 QuartzCore`CA::Transaction::commit() + 395
    frame #12: 0x018f9b17 QuartzCore`+[CATransaction commit] + 52
    frame #13: 0x000399bf MyApp`-[HomeViewController catchTourScrollViewScreenshotViewAndAnimateItToButton](self=0x0b4e5210, _cmd=0x006f381a) + 1903 at HomeViewController.m:197
    frame #14: 0x0391f663 libobjc.A.dylib`-[NSObject performSelector:] + 62
    frame #15: 0x0003c383 MyApp`-[NSObject(self=0x0b4e5210, _cmd=0x006ef5ad, selector=0x006f381a) performSelectorIfRespondsToIt:] + 243 at NSObject+PerformSelectorIfRespondsToIt.m:22
    frame #16: 0x00042506 MyApp`__44-[TourViewController closeTourWithAnimation]_block_invoke268(.block_descriptor=0x0b6985a0, finished='\x01') + 86 at TourViewController.m:419
    frame #17: 0x01af0df6 UIKit`-[UIViewAnimationBlockDelegate _didEndBlockAnimation:finished:context:] + 223
    frame #18: 0x01ae3d66 UIKit`-[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 237
    frame #19: 0x01ae3f04 UIKit`-[UIViewAnimationState animationDidStop:finished:] + 68
    frame #20: 0x12b6ff28 UIKit`-[UIViewAnimationStateAccessibility(SafeCategory) animationDidStop:finished:] + 66
    frame #21: 0x018df7d8 QuartzCore`CA::Layer::run_animation_callbacks(void*) + 284
    frame #22: 0x03a90014 libdispatch.dylib`_dispatch_client_callout + 14
    frame #23: 0x03a807d5 libdispatch.dylib`_dispatch_main_queue_callback_4CF + 296
    frame #24: 0x03f3eaf5 CoreFoundation`__CFRunLoopRun + 1925
    frame #25: 0x03f3df44 CoreFoundation`CFRunLoopRunSpecific + 276
    frame #26: 0x03f3de1b CoreFoundation`CFRunLoopRunInMode + 123
    frame #27: 0x044c67e3 GraphicsServices`GSEventRunModal + 88
    frame #28: 0x044c6668 GraphicsServices`GSEventRun + 104
    frame #29: 0x01aa5ffc UIKit`UIApplicationMain + 1211
    frame #30: 0x0000285d MyApp`main(argc=1, argv=0xbffff3f4) + 141 at main.m:16
    frame #31: 0x00002785 MyApp`start + 53

打开 NSZombie 不会提供任何更有用的调试信息。

在升级到 Xcode 4.6.3 (4H1503) 之前使用的相同代码。需要注意的是:在模拟器中，动画有时会暂停，点击它会恢复。这个奇怪的人工制品是出现问题的迹象，但我当时还不知道。

我错过了什么吗？
如果这是一个已知的错误，是否有任何解决方法？

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一些研究笔记:similar question has been asked on SO ，但接受的答案只是通过将路径动画更改为线性平移来“解决”问题。

我的问题似乎也与此处的博文非常相似:http://www.blogosfera.co.uk/2013/08/exc_bad_access-while-using-coreanimation/

Answer 1

这真的不是什么答案，更多的是试图给你一个工具来寻找更多的线索。希望比我有更多线索的人会插话。

• 打开 malloc 堆栈日志记录。
• 重现崩溃。
• 检查寄存器；如果 $r0 或 $r1 看起来像堆分配，则获取所述地址的 malloc 历史记录。

如果任一事件的最后一个事件是 FREE，则数据缓冲区(或对象)将被过早释放。 (有关获取 malloc 历史记录的信息，请参阅 http://lldb.llvm.org/lldb-gdb.html)。

现在，即使它确认这是一个过早的释放，它实际上可能不会帮助您那个。如果是这样，它会告诉你这是一个竞争条件。不幸的是，修复它实际上是不可能的，但可能有一种解决方法。如果您能弄清楚您控制的哪个对象可能已经分配了过早的 free()d 缓冲区，那么您应该能够持有对所述对象的强引用，直到动画完全完成。

请提交错误，附上崩溃的二进制文件。

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此外，打开 malloc scribble。这将确保释放的内存在释放后立即被丢弃，这应该使崩溃尽快发生。