Question

我有一个将SKSpriteNode从一个点移动到另一个点的函数。当我打电话一次时，它工作正常。但是当我多次调用它时，整个程序崩溃了。

    func play()
    {
        self.moveNode()
        self.moveNode()
    }

    func moveNode()
    {
        let player = SKSpriteNode(imagenamed: "player.png")
        player.position = CGPointMake(500.0, 500.0)
        self.addChild(player)
        let fire = SKAction.moveTo(CGPointMake(100.0, 100.0), duration: 0.25)
        player.runAction(fire)
    }

这些是崩溃日志，（我不知道如何阅读它们所以我发布了所有内容，我运行了5-6次）：

2015-06-15 20:55:49.616 The Game[2099:42388] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Attemped to add a SKNode which already has a parent: name:'(null)' texture:[ 'player.png' (640 x 480)] position:{500, 500} size:{64, 48} rotation:0.00' * First throw call stack: ( 
0 CoreFoundation 0x0000000101bc6a75 exceptionPreprocess + 165 
1 libobjc.A.dylib 0x00000001038d4bb7 objc_exception_throw + 45 
2 CoreFoundation 0x0000000101bc69ad +[NSException raise:format:] + 205 
3 SpriteKit 0x00000001024881a6 -[SKNode addChild:] + 111 
4 The Game 0x00000001019d2156 _TFC13The_Game6Level111createNodefS0_FT_T_ + 678 
5 The Game 0x00000001019d21fb _TFC13The_Game6Level110moveNodefS0_FT_T_ + 59 
6 The Game 0x00000001019d0bc9 _TFC13The_Game6Level16updatefS0_FSdT_ + 73 
7 The Game 0x00000001019d0c08 _TToFC13The_Game6Level16updatefS0_FSdT_ + 40 
8 SpriteKit 0x000000010247bb68 -[SKView(Private) _update:] + 1106 
9 SpriteKit 0x00000001024792d9 -[SKView renderCallback:shouldBlock:] + 837 
10 SpriteKit 0x0000000102476391 __29-[SKView setUpRenderCallback]_block_invoke + 56 
11 SpriteKit 0x00000001024a2df4 -[SKDisplayLink _callbackForNextFrame:] + 256 
12 QuartzCore 0x000000010652a5c7 _ZN2CA7Display15DisplayLinkItem8dispatchEv + 37 
13 QuartzCore 0x000000010652a48f _ZN2CA7Display11DisplayLink14dispatch_itemsEyyy + 315 
14 CoreFoundation 0x0000000101b2e6c4 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION + 20 
15 CoreFoundation 0x0000000101b2e285 __CFRunLoopDoTimer + 1045 
16 CoreFoundation 0x0000000101af159d __CFRunLoopRun + 1901 
17 CoreFoundation 0x0000000101af0bc6 CFRunLoopRunSpecific + 470 
18 GraphicsServices 0x0000000108fc6a58 GSEventRunModal + 161 
19 UIKit 0x000000010260f580 UIApplicationMain + 1282 
20 The Game 0x00000001019d872e top_level_code + 78 
21 The Game 0x00000001019d876a main + 42 
22 libdyld.dylib 0x00000001040c2145 start + 1 ) libc++abi.dylib: terminating with uncaught exception of type NSException (lldb)

Answer 1

问题是您的代码正在向您的播放器节点调用addChild，即使它已经有父节点。

在您的代码moveNode中，每次运行self.addChild(player)时都会调用moveNode。如果您不止一次运行该功能，那将会导致游戏崩溃。

解决方案是在另一个只调用一次的函数中初始化您的节点，或运行条件检查以防止代码多次运行addChild函数。

Answer 2

通过这种方式调用方法来使用动画真是个坏主意。这是一种用包装基本命令的顺序和重复动作做同样事情的方法：

let move = SKAction.moveTo(CGPointMake(CGRectGetMidX(self.frame), CGRectGetMidY(self.frame)), duration: 0)
let fire = SKAction.moveTo(CGPointMake(100.0, 100.0), duration: 0.25)
let wait = SKAction.waitForDuration(0.5)

let sequence = SKAction.sequence([move, fire, wait])
let repeated = SKAction.repeatAction(sequence, count:2)

player.runAction(repeated)

多次调用函数时程序崩溃

2 个答案: