touchesBegan If语句问题

Question

我在试着检测节点是否是敌人。如果是的话，我想把它移除。我正在尝试使用触摸节点的名称来检测这一点。我能够检测到节点的名称是否是敌人，但我不知道如何删除它。谢谢你的帮助！)

以下是所有相关代码：

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

代码的这一部分是有问题的：

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

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

变量nodes是一个SKNode实例的数组；对整个数组调用SKNode方法removeFromParent() (仅对其单个元素)是没有任何意义的。

您已经成功地测试了.first元素的名称；同样要删除它：

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

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

或者更好的分配(一轮移除多个敌人)：

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

最后，上面的代码有一个更“滑动”的版本：

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