Ios 子类化SKSpriteNode时物理体的问题？

我在子类化SKSpriteNode时遇到了一个问题。下面是我对子类的实现：

@implementation SSSquirrel
- (id) init {
    if (self = [super init]) {

        // Create Squirrel and physics body
        SKSpriteNode *squirrel = [SKSpriteNode spriteNodeWithImageNamed:@"squirrelNormal"];
        squirrel.physicsBody = [SKPhysicsBody bodyWithCircleOfRadius:squirrel.size.width/2 - 10];
        squirrel.physicsBody.dynamic = NO;
        squirrel.physicsBody.affectedByGravity = NO;
        squirrel.physicsBody.restitution = 0.8;
        squirrel.physicsBody.friction = 0.1;
        squirrel.zPosition = 1.0;

        [self addChild:squirrel];

    }
    return self;
}

@end

然后我在我的主要游戏场景中创建了一只松鼠，如下所示：

    SSSquirrel *squirrel1 = [[SSSquirrel alloc] init];
    squirrel1.position = CGPointMake(offset, self.frame.size.height - offset);
    [self addChild:squirrel1];

一切都很好。但是在游戏中，我尝试在触摸开始时“暂停”松鼠的物理体，然后在触摸结束时重新启用它（tempSquirrelBody是场景的SKPhysicsBody实例变量）。基本上，我试图给人一种错觉，即当用户触摸屏幕时，松鼠正朝着用户和其他物体移动

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */

for (UITouch *touch in touches) {

    tempSquirrelBody = squirrel1.physicsBody;
    squirrel1.physicsBody = nil;

    CGPoint newPosition = squirrel1.position;
    newPosition.x -= 60;
    newPosition.y += 60;

    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelUp"];

}
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch ends */

for (UITouch *touch in touches) {

    CGPoint newPosition = squirrel1.position;
    newPosition.x += 60;
    newPosition.y -= 60;
    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelNormal"];

    squirrel1.physicsBody = tempSquirrelBody;

}

}

不幸的是，这是行不通的；当physicsbody设置为nil时，physicsbody不会悬浮，松鼠会与其他对象碰撞。当我将代码从SSSquirrel类移动到游戏场景时，它仍然有效。我做错了什么

---

谢谢

将

冲突位掩码设置为
0
而不是将整个
physicsBody
设置为
nil
不是更容易吗

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch begins */

for (UITouch *touch in touches) {

    squirrel1.physicsBody.collisionBitMask = 0;

    CGPoint newPosition = squirrel1.position;
    newPosition.x -= 60;
    newPosition.y += 60;

    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelUp"];

}
}

- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
/* Called when a touch ends */

for (UITouch *touch in touches) {

    CGPoint newPosition = squirrel1.position;
    newPosition.x += 60;
    newPosition.y -= 60;
    squirrel1.position = newPosition;
    squirrel1.texture = [SKTexture textureWithImageNamed:@"squirrelNormal"];

    squirrel1.physicsBody.collisionBitMask = 0xFFFFFFFF;

}

}

我终于意识到我做错了什么。在我的SSSquirrel课程中，我将物理体分配给了SKSpriteNode而不是self，这使得我在课堂外无法访问它。是的，这是一种更好的阻止碰撞的方法，但是，我的方法仍然正确。结果是我把物理体分配给了SKSpriteNode而不是self，这使得我在课堂外无法访问它。