ios - touchesBegan If语句问题

Question

我正在尝试检测一个节点是否是敌人。如果是，我想删除它。我正在尝试使用 touched nodes 名称来检测这一点。我能够检测到节点的名称是否为敌人，但我不知道如何删除它。谢谢您的帮助! :)

这里是所有相关代码:

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    let touch = touches.first!
    let location = touch.location(in: self)
    let nodes = self.nodes(at: location);
    let name = nodes.first?.name;

    if (name == "enemy") {
        nodes.removeFromParent() // this doesn't work
    }
}

@objc open func spawnEnemies() {
    let randomNumber = randomBetween(min: Int(-150), max: Int(self.frame.width + 150))
    print(randomNumber)
    print(self.frame.width)
    var enemy = SKSpriteNode(imageNamed: "triangle")
    enemy.position = CGPoint(x: CGFloat(randomNumber), y: self.frame.height + 250)
    enemy.name = "enemy";
    enemy.zPosition = 6.0;

    enemy.physicsBody?.allowsRotation = false

    enemy.zRotation = 0
    enemy.physicsBody?.affectedByGravity = false
    enemy.physicsBody = SKPhysicsBody(texture: enemy.texture!, size: enemy.texture!.size())
    enemy.physicsBody?.affectedByGravity = false
    enemy.physicsBody?.isDynamic = true
    enemy.physicsBody?.categoryBitMask = enemyCategory
    enemy.physicsBody?.collisionBitMask = blockerCategory
    enemy.physicsBody?.contactTestBitMask = blockerCategory
    enemy.setScale(CGFloat(0.03))
    addChild(enemy)
}

Answer 1

这部分代码有问题:

let nodes = self.nodes(at: location);
let name = nodes.first?.name;

if (name == "enemy") {
    nodes.removeFromParent() // this doesn't work
}

您的变量 nodes 是 SKNode 实例的数组；对整个数组(仅对其单个元素)调用SKNode 方法removeFromParent() 没有任何意义。

您已经成功测试了.first 元素的名称；执行相同的操作以将其删除:

let nodes = self.nodes(at: location);
let name = nodes.first?.name;

if (name == "enemy") {
    nodes.first?.removeFromParent()
}

或者更好的方法(在一轮中移除多个敌人):

for node in self.nodes(at: location) {
    if node.name == "enemy" {
        node.removeFromParent()
    }
}

最后，上面代码的更“快速”版本:

nodes.filter({ (node) -> Bool in
    return node.name == "enemy"
}).forEach({ (enemy) in
    enemy.removeFromParent()
})