SpriteKit：touchesEnded / mouseUp发送到已发布的对象

Question

我遇到的问题是，在发布之前启动了触摸/点击时，仍会在已发布的对象上调用touchesEnded（在iOS上）或mouseUp（在macOS上）。此行为导致我的项目崩溃。我使用SceneKit和SpriteKit叠加层制作了一个精简程序，但我不确定我做错了什么。

我已经开始使用SceneKit游戏模板（iOS或macOS），并且我添加了两个类：

在GameViewController.m结束时 - （void）awakeFromNib我添加了这个：

OverlayScene *overlay=[OverlayScene sceneWithSize:self.gameView.frame.size];// init the overlay
[overlay setupButtons];// create a small GUI menu
[self.gameView setOverlaySKScene:overlay];// add the overlay to the SceneKit view

然后是两个班 OverlayScene.m：

#import <SpriteKit/SpriteKit.h>
#import "Button.h"

@interface OverlayScene : SKScene
-(void)setupButtons;
@end

OverlayScene.m：

#import "OverlayScene.h"
@implementation OverlayScene

-(void)setupButtons{//showing a menu mockup 
    NSLog(@"setupButtons");
    srand((unsigned)time(NULL));// seed the RNG
    [self removeAllChildren];//remove all GUI element (only one button or nothing (in the first call)
    Button *b=[[Button alloc] initWithSelector:@selector(setupButtons) onObject:self];// a new button
    b.position=CGPointMake(rand()%300, rand()%300);// just a random position so we can see the change
    [self addChild:b];// finally attach the button to the scene
}

@end

Button.h：

#import <SpriteKit/SpriteKit.h>
@interface Button : SKSpriteNode{
    SEL selector;//the method which is supposed to be called by the button
    __weak id selectorObj;//the object on which the selector is called
}
-(id)initWithSelector:(SEL)s onObject:(__weak id)o;
@end

Button.m：

#import "Button.h"
@implementation Button
-(id)initWithSelector:(SEL)s onObject:(__weak id)o{
    //self=[super initWithColor:[UIColor purpleColor] size:CGSizeMake(200, 60)];//this is the code for iOS
    self=[super initWithColor:[NSColor purpleColor] size:CGSizeMake(200, 60)];// this is for macOS
    selector=s;//keep the selector with the button
    selectorObj=o;
    [self setUserInteractionEnabled:YES];//enable touch handling
    return self;
}
//-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{//called on iOS
-(void)mouseDown:(NSEvent *)event{//called on macOS
    [selectorObj performSelector:selector];//we are calling the method which was given during the button initialization
}
@end

当您单击按钮时，它会按预期移除（并由弧释放）并创建一个新按钮。只要按住鼠标按钮，一切都很好。当您释放它时，应用程序崩溃，因为mouseUp事件被发送到已删除的按钮：