Sprite Kit中的多点触控手势

同时移动多个节点非常简单。关键是要独立跟踪每个触摸事件。一种方法是维护一个字典，该字典使用touch事件作为键，并使用要移动的节点作为值。

首先，声明字典

var selectedNodes:[UITouch:SKSpriteNode] = [:]

以touch事件为键，将每个触摸的精灵添加到字典中

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {    for touch in touches {        let location = touch.location(in:self)        if let node = self.atPoint(location) as? SKSpriteNode { // Assumes sprites are named "sprite" if (node.name == "sprite") {     selectedNodes[touch] = node }        }    }}

根据需要更新子画面的位置

override func touchesMoved(_ touches: Set<UITouch>, with event: UIEvent?) {    for touch in touches {        let location = touch.location(in:self)        // Update the position of the sprites        if let node = selectedNodes[touch] { node.position = location        }    }}

触摸结束后，从字典中删除精灵

override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {    for touch in touches {        if selectedNodes[touch] != nil { selectedNodes[touch] = nil        }    }}