此错误仅发生在实际设备上。在 Xcode 6 中的模拟器上运行时，它不会崩溃。
我正在创造外太空，并有随机流星划过天空。在场景中，[goToSpace] 被调用，它通过使用三个 SKEmitterNode 来模拟深度来设置星场。然后初始化一个计时器，它发送星星射击。
在星域的初始化中，需要提前模拟三个SKEmitterNodes，以获得满天星辰。当调用 [emitterNode1 advanceSimulationTime:lifetime] 行时，我得到 exc_bad_access。我按照教程启用了 NSZombie，但没有帮助。
我无法终生追查为什么我会获得 exc_bad_access。我使用 Parse.com 的崩溃报告，它给出了这个堆栈：
> Stack Trace Thread 0 (crashed) 0 libsystem_platform.dylib
> OSSpinLockLock @ 0x4 1 SpriteKit SKSpinLockSync(int*, void ()
> block_pointer) @ 0x20 2 SpriteKit
> -[SKTexture loadImageData] @ 0xec 3 SpriteKit
> -[SKTexture size] @ 0x28 4 SpriteKit SKCEmitterSprite::update(double) @ 0x117c 5 CorpBoard @ 0x48d44 6 CorpBoard @ 0xfbc50 7 CorpBoard @
> 0xfa6f0 8 CorpBoard @ 0xfa070 9 UIKit
> -[UITableView _createPreparedCellForGlobalRow:withIndexPath:willDisplay:] @ 0x21c 10 UIKit
> -[UITableView _updateVisibleCellsNow:isRecursive:] @ 0x934 11 UIKit
> -[UITableView layoutSubviews] @ 0xa8 12 UIKit
> -[UIView(CALayerDelegate) layoutSublayersOfLayer:] @ 0x238 13 QuartzCore
> -[CALayer layoutSublayers] @ 0xa4 14 QuartzCore CA::Layer::layout_if_needed(CA::Transaction*) @ 0x13c 15 QuartzCore
> CA::Layer::layout_and_display_if_needed(CA::Transaction*) @ 0x1c 16
> QuartzCore CA::Context::commit_transaction(CA::Transaction*) @ 0x110
> 17 QuartzCore CA::Transaction::commit() @ 0x1b0 18 QuartzCore
> CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned
> long, void*) @ 0x4c 19 CoreFoundation
> __CFRUNLOOP_IS_CALLING_OUT_TO_AN_OBSERVER_CALLBACK_FUNCTION__ @ 0x1c 20 CoreFoundation
> __CFRunLoopDoObservers @ 0x164 21 CoreFoundation
> __CFRunLoopRun @ 0x340 22 CoreFoundation CFRunLoopRunSpecific @ 0x188 23 GraphicsServices GSEventRunModal @ 0xa4 24 UIKit UIApplicationMain
> @ 0x5cc 25 CorpBoard @ 0x5be80 26 libdyld.dylib start @ 0x0 Thread 1 0
> libsystem_kernel.dylib kevent64 @ 0x8 1 libdispatch.dylib
> _dispatch_mgr_invoke @ 0x110 2 libdispatch.dylib
> _dispatch_mgr_thread @ 0x30 Thread 2 0 libsystem_kernel.dylib
> __workq_kernreturn @ 0x8 1 libsystem_pthread.dylib
> _pthread_wqthread @ 0x3dc 2 libsystem_pthread.dylib start_wqthread @ 0x0 Thread 3 0 libsystem_kernel.dylib
> __workq_kernreturn @ 0x8 1 libsystem_pthread.dylib
> _pthread_wqthread @ 0x3dc 2 libsystem_pthread.dylib start_wqthread @ 0x0 Thread 4 0 libsystem_kernel.dylib
> __workq_kernreturn @ 0x8 1 libsystem_pthread.dylib
> _pthread_wqthread @ 0x3dc 2 libsystem_pthread.dylib start_wqthread @ 0x0 Thread 5 0 libsystem_kernel.dylib
> __workq_kernreturn @ 0x8 1 libsystem_pthread.dylib
> _pthread_wqthread @ 0x3dc 2 libsystem_pthread.dylib start_wqthread @ 0x0 Thread 6 0 libsystem_kernel.dylib
> __workq_kernreturn @ 0x8 1 libsystem_pthread.dylib
> _pthread_wqthread @ 0x3dc 2 libsystem_pthread.dylib start_wqthread @ 0x0 Thread 7 0 libsystem_kernel.dylib mach_msg_trap @ 0x8 1
> libsystem_kernel.dylib mach_msg @ 0x44 2 CoreFoundation
> __CFRunLoopServiceMachPort @ 0xc4 3 CoreFoundation
> __CFRunLoopRun @ 0x3a8 4 CoreFoundation CFRunLoopRunSpecific @ 0x188 5 Foundation
> -[NSRunLoop(NSRunLoop) runMode:beforeDate:] @ 0x138 6 Foundation
> -[NSRunLoop(NSRunLoop) run] @ 0x5c 7 CorpBoard @ 0x206a28 8 Foundation
> __NSThread__main__ @ 0x42c 9 libsystem_pthread.dylib
> _pthread_body @ 0xa0 10 libsystem_pthread.dylib
> _pthread_start @ 0x9c 11 libsystem_pthread.dylib thread_start @ 0x0 Thread 8 0 libsystem_kernel.dylib mach_msg_trap @ 0x8 1
> libsystem_kernel.dylib mach_msg @ 0x44 2 CoreFoundation
> __CFRunLoopServiceMachPort @ 0xc4 3 CoreFoundation
> __CFRunLoopRun @ 0x3a8 4 CoreFoundation CFRunLoopRunSpecific @ 0x188 5 CFNetwork
> +[NSURLConnection(Loader) _resourceLoadLoop:] @ 0x1b4 6 Foundation
> __NSThread__main__ @ 0x42c 7 libsystem_pthread.dylib
> _pthread_body @ 0xa0 8 libsystem_pthread.dylib
> _pthread_start @ 0x9c 9 libsystem_pthread.dylib thread_start @ 0x0 Thread 9 0 libsystem_kernel.dylib
> __select @ 0x8 1 CoreFoundation
> __CFSocketManager @ 0x290 2 libsystem_pthread.dylib
> _pthread_body @ 0xa0 3 libsystem_pthread.dylib
> _pthread_start @ 0x9c 4 libsystem_pthread.dylib thread_start @ 0x0 Thread 10 0 libsystem_kernel.dylib mach_msg_trap @ 0x8 1
> libsystem_kernel.dylib mach_msg @ 0x44 2 CoreFoundation
> __CFRunLoopServiceMachPort @ 0xc4 3 CoreFoundation
> __CFRunLoopRun @ 0x3a8 4 CoreFoundation CFRunLoopRunSpecific @ 0x188 5 CoreFoundation CFRunLoopRun @ 0x6c 6 CoreMotion @ 0x4298c 7
> libsystem_pthread.dylib
> _pthread_body @ 0xa0 8 libsystem_pthread.dylib
> _pthread_start @ 0x9c 9 libsystem_pthread.dylib thread_start @ 0x0 Thread 11 0 libsystem_kernel.dylib
> __workq_kernreturn @ 0x8 1 libsystem_pthread.dylib
> _pthread_wqthread @ 0x3dc 2 libsystem_pthread.dylib start_wqthread @ 0x0
相关代码：
NSTimer *space;
-(void)goToSpace {
[self shootingStar];
double lifetime;
SKEmitterNode *emitterNode1 = [self starFieldEmitter:[SKColor lightGrayColor] starSpeedY:1 starsPerSecond:.1 starScaleFactor:0.08];
lifetime = self.frame.size.height * [[UIScreen mainScreen] scale] / 1;
[emitterNode1 advanceSimulationTime:lifetime];
emitterNode1.zPosition = -10;
[self addChild:emitterNode1];
SKEmitterNode *emitterNode2 = [self starFieldEmitter:[SKColor lightGrayColor] starSpeedY:.8 starsPerSecond:.08 starScaleFactor:0.06];
emitterNode2.zPosition = -11;
lifetime = self.frame.size.height * [[UIScreen mainScreen] scale] / .8;
[emitterNode2 advanceSimulationTime:lifetime];
[self addChild:emitterNode2];
SKEmitterNode *emitterNode3 = [self starFieldEmitter:[SKColor grayColor] starSpeedY:.5 starsPerSecond:.5 starScaleFactor:0.03];
emitterNode3.zPosition = -12;
lifetime = self.frame.size.height * [[UIScreen mainScreen] scale] / .5;
[emitterNode3 advanceSimulationTime:lifetime];
[self addChild:emitterNode3];
space = [NSTimer scheduledTimerWithTimeInterval:2 target:self selector:@selector(shootingStar) userInfo:nil repeats:YES];
}
-(SKEmitterNode *)starFieldEmitter:(SKColor *)color starSpeedY:(CGFloat)starSpeedY starsPerSecond:(CGFloat)starsPerSecond starScaleFactor:(CGFloat) starScaleFactor {
SKEmitterNode *emitterNode = [SKEmitterNode node];
CGFloat lifetime = self.frame.size.height * [[UIScreen mainScreen] scale] / starSpeedY;
emitterNode.particleTexture = [SKTexture textureWithImage:[UIImage imageNamed:@"stars"]];
emitterNode.particleBirthRate = starsPerSecond;
emitterNode.particleColor = [SKColor lightGrayColor];
emitterNode.particleSpeed = starSpeedY * -1;
emitterNode.particleScale = starScaleFactor;
emitterNode.particleColorBlendFactor = 1;
emitterNode.particleLifetime = lifetime;
int rndValue = 1 + arc4random() % (45 - 1);
emitterNode.particleRotation = rndValue;
emitterNode.position = CGPointMake(self.frame.size.width / 2, self.frame.size.height);
emitterNode.particlePositionRange = CGVectorMake(self.frame.size.width, self.frame.size.height);
return emitterNode;
}
-(BOOL) getYesOrNo {
int tmp = (arc4random() % 30)+1;
if(tmp % 5 == 0)
return YES;
return NO;
}
-(void)shootingStar {
BOOL left = [self getYesOrNo];
int xPos = 0;
int height = self.frame.size.height;
int yPos = 1 + arc4random() % (height - 1);
if (left) {
xPos = -50;
} else {
xPos = self.frame.size.width + 50;
}
SKEmitterNode *shootingstar = [SKEmitterNode node];
shootingstar = [NSKeyedUnarchiver unarchiveObjectWithFile:[[NSBundle mainBundle] pathForResource:@"spark" ofType:@"sks"]];
CGPoint xy = CGPointMake(xPos, yPos);
shootingstar.position = xy;
shootingstar.name = @"shootingStar";
shootingstar.zPosition = -2.0;
shootingstar.targetNode = self.scene;
[self addChild:shootingstar];
//make random size to simulate distance
float val = [self randFloatBetween:.1 and:.5];
SKAction *scale = [SKAction scaleBy:val duration:0];
[shootingstar runAction: scale completion:nil];
//now set speed depending on size (smaller = farther = slower)
int dur = 0;
if (val < .2) dur = 5;
else if (val < .35) dur = 3;
else dur = 2;
int moveY = -500 + arc4random() % (500 - -500);
int moveX;
if (left) {
moveX = 500;
} else {
moveX = -500;
}
SKAction *move = [SKAction moveByX:moveX y:moveY duration:dur];
int waitDuration = 2 + arc4random() % (5 - 2);
SKAction *wait = [SKAction waitForDuration:waitDuration];
SKAction *sequence = [SKAction sequence:@[wait, move]];
[shootingstar runAction:sequence completion:^{
[shootingstar removeFromParent];
//[self shootingStar];
}];
}
-(float) randFloatBetween:(float)low and:(float)high {
float diff = high - low;
return (((float) rand() / RAND_MAX) * diff) + low;
}