Question

我正在运行Yosemite公共测试版＆amp; Xcode6 Beta 4

基于OSX SceneKit模板，我试图确定点击了哪个节点。这是mouseDown函数，主要来自模板代码。

标记为＃1的评论很有效，但是我试图理解为什么代码注释＃2，＃3和＃4不能编译，或者错误是什么我

搜索错误我没有找到似乎适用于我的案例的结果。

＃2的错误似乎通常适用于类型转换，我不认为这里有任何类型转换。

＃3的错误让我完全迷失了。

并且＃4的错误似乎SCNNode没有名称属性，但肯定会。

override func mouseDown(theEvent: NSEvent) {
    /* Called when a mouse click occurs */

    // check what nodes are clicked
    let p = gameView.convertPoint(theEvent.locationInWindow, fromView: nil)
    let hitResults = gameView.hitTest(p, options: nil)

    // check that we clicked on at least one object
    if (hitResults.count > 0){

        // retrieved the first clicked object
        let result: AnyObject = hitResults[0]

// #1 This works
        if let myNode: SCNNode = result.node? {
            if myNode.name? == "Die" {
                println("Node is named Die")
            }
        }

// #2 This does not work
        // error: Could not find an overload for the 'node' that accepts the supplied arguments
        if let myNode = result.node? {
            if myNode.name? == "Die" {
                println("Node is named Die")
            }
        }

// #3 This does not work either
        // error: Type 'String?' does not confrom to protocol '_RawOptionSet'
        if result.node?.name? == "Die" {
            println("Node is named Die")
        }

// #4 This does not work either
        // error: 'SCNNode!' does not have a member named 'name'
        if let myName = result.node?.name? {
            if myName == "Die" {
                println("Node is named Die")
            }
        }

        // get its material
        let material = result.node!.geometry.firstMaterial;

        // highlight it
        SCNTransaction.begin()
        SCNTransaction.setAnimationDuration(0.5)

        // on completion - unhighlight
        SCNTransaction.setCompletionBlock() {
            SCNTransaction.begin()
            SCNTransaction.setAnimationDuration(0.5)

            material.emission.contents = NSColor.blackColor()

            SCNTransaction.commit()
        }

        material.emission.contents = NSColor.redColor()

        SCNTransaction.commit()

    }

    super.mouseDown(theEvent)
}

Answer 1

＃2，＃3和＃4的失败都是因为缺乏类型。你说：

＃2的错误似乎通常适用于类型转换，我不认为这里有任何类型转换。

但是，当您尝试以result形式访问AnyObject时，您宣布SCNNode为var item: AnyObject? = nil item = map["SWLFlexFormat"] if let value: AnyObject = item { configuration.formatter = getConfiguredFlexFormatter(configuration, item: value); } func getConfiguredFlexFormatter(configuration: LoggerConfiguration, item: AnyObject) -> LogFormatter? { if let formatString: String = item as? String { var formatter = FlexFormatter.logFormatterForString(formatString); return formatter } return nil }，因此当然需要进行某些类型转换发生。

我之前已经看过这个和词典一起工作了。我不仅明确了类型，我还预先测试了类型：

{{1}}

Swift链接选项

1 个答案: