快速解析给定 elementName 的属性名称

Question

这是我的网址的一部分

<cities>
  <country name="Абхазия">
    <city id="37188" region="27028" head="" type="3" country="Абхазия" part="" resort="" climate="">Новый Афон</city>
    <city id="37178" region="10282" head="" type="3" country="Абхазия" part="" resort="" climate="">Пицунда</city>
    <city id="37187" region="37187" head="" type="3" country="Абхазия" part="" resort="" climate="">Гудаута</city>
    <city id="37172" region="10280" head="" type="3" country="Абхазия" part="" resort="" climate="">Гагра</city>
    <city id="37189" region="10281" head="0" type="3" country="Абхазия" part="" resort="0" climate="">Сухум</city>
  </country>

用户输入城市名称，例如:“Пицунда”，我想获取其 ID。对于“Пицунда”，ID 为“10282”。

下面我发布了我的不起作用的代码。

var parser: NSXMLParser!
var city: String = String()
var ifDirOK = false
var ifCityNameOK = false


override func viewDidLoad() {
    super.viewDidLoad()

    let url: NSURL = NSURL(string: "https://pogoda.yandex.ru/static/cities.xml")!

    parser = NSXMLParser(contentsOfURL: url)
    parser.delegate = self
    parser.parse()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}



func parser(parser: NSXMLParser!, didStartElement elementName: String!, namespaceURI: String!, qualifiedName qName: String!, attributes attributeDict: [NSObject : AnyObject]!) {
    //let cityID = attributeDict ["id"] as? NSString
    if (elementName == "city"){
        ifDirOK = true
    }
}

func parser(parser: NSXMLParser!, foundCharacters string: String!) {
    var data = string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())
    if (data == city){
        ifCityNameOK = true
    }
}

func parser(parser: NSXMLParser!, foundAttributeDeclarationWithName attributeName: String!, forElement elementName: String!, type: String!, defaultValue: String!) {
    if (ifDirOK && ifCityNameOK){
        println("\(attributeName)")
    }
}

func parser(parser: NSXMLParser!, didEndElement elementName: String!, namespaceURI: String!, qualifiedName qName: String!) {
}

毕竟，我想将 id 传递给另一个 URL 文件 (export.yandex.ru/weather-ng/forecasts/{id of the city}.xml) 并解析它。我是否需要创建另一个 Swift 类并以某种方式将其与第一个类连接？

Answer 1

构建 [city:id] 字典可能是您的一个解决方案。我根据 http://www.codeproject.com/Articles/248883/Objective-C-Fundamentals-NSXMLParser 关于 NSXMLParser 生命周期的文章实现了一个简单的解决方案.

当元素启动时调用以下方法。您可以检索城市 ID 属性并将其保存在实例级变量中，以便您可以在下一个方法中使用它。

func parser(parser: NSXMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [NSObject : AnyObject]) 

然后，当解析器看到开始和结束之间的任何内容时，将调用以下方法。

func parser(parser: NSXMLParser!, foundCharacters string: String!) 

因此，您可以从这里获取城市名称。现在我们有了城市 ID 和城市名称，可以将新项目添加到 [city:id] 字典中。

一旦建立了字典，搜索就会非常简单。

这是我的工作测试代码。

class ViewController: UIViewController ,NSXMLParserDelegate{
    var parser: NSXMLParser!
    var city: String = String()
    var ifDirOK = false
    var ifCityNameOK = false
     var element : String?
    var value: String=String()
    var dic = Dictionary<String,String>()
    var currentCityId:String?
    @IBOutlet weak var result: UILabel!

    @IBOutlet weak var search: UITextField! //search text

    @IBAction func ActionGoGetIt(sender: AnyObject) {

        self.result.text=dic[self.search.text]
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        let url: NSURL = NSURL(string: "https://pogoda.yandex.ru/static/cities.xml")!

        parser = NSXMLParser(contentsOfURL: url)
        parser.delegate = self
        parser.parse()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }



    func parser(parser: NSXMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [NSObject : AnyObject]) {
        element = elementName

        if (element == "city"){
            ifDirOK = true
            let cityID = attributeDict ["id"] as? NSString
            self.currentCityId = cityID  as? String

        }
    }

    func parser(parser: NSXMLParser!, foundCharacters string: String!) {
        var data = string.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet())

        if (!data.isEmpty){
             if (element == "city"){
                    dic[data] = self.currentCityId as String?
            }

        }
    }

    func parser(parser: NSXMLParser, foundAttributeDeclarationWithName attributeName: String, forElement elementName: String, type: String?, defaultValue: String?) {
        if (ifDirOK && ifCityNameOK){
            println("\(attributeName)")
        }
    }

    func parser(parser: NSXMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?) {

    }

}