ios - 来自 Web 服务的数据查找未在标签中正确显示

Question

我有两个对 Web 服务的调用，我试图将这些调用显示在辅助 View 的标签中。

第一次查找或调用发生在主视图 Controller 加载期间，如下所示:

override func viewDidLoad() {
    super.viewDidLoad()
getAddress()
}

func getAddress() {
    let URL_GET_ADDR:String = "http://www.webserver.com/apps/getmailingaddr.php"
    let requestURL = NSURL(string: URL_GET_ADDR)
    let request = NSMutableURLRequest(url: requestURL! as URL)
    request.httpMethod = "POST"
    let task = URLSession.shared.dataTask(with: request as URLRequest){
        data, response, error in
        //exiting if there is some error
        if error != nil{
            print("error is \(error)")
            return;
        }
        //parsing the response
        do {
            //converting resonse to NSDictionary
            //var teamJSON: NSDictionary!
            self.teamJSON =  try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary

            //getting the JSON array teams from the response
            let address: NSArray = self.teamJSON["mailing"] as! NSArray

            //looping through all the json objects in the array teams
            for i in 0 ..< address.count{

                //getting the data at each index
                let addrName:String = (address[i] as! NSDictionary)["name"] as! String!
                let addrAddr1:String = (address[i] as! NSDictionary) ["address1"] as! String!
                let addrAddr2:String = (address[i] as! NSDictionary)["address2"] as! String!
                let addrCity:String = (address[i] as! NSDictionary)["city"] as! String!
                let addrState:String = (address[i] as! NSDictionary)["state"] as! String!
                let addrZipcode:Int = (address[i] as! NSDictionary)["zipcode"] as! Int!
            }

        } catch {
            print(error)
        }
    }
    task.resume()
}

我使用以下内容将此数据传递到联系人 View Controller :

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
   if let ContactsViewController = segue.destination as? ContactsViewController {
   ContactsViewController.myAddress = teamJSON
}

到目前为止一切都很好。现在，在联系人 View Controller 中，我正在使用以下命令执行联系人查找:

override func viewDidLoad() {
   super.viewDidLoad()
   myLabel = ""
   // Do any additional setup after loading the view, typically from a nib.
   contactsLabel.lineBreakMode = NSLineBreakMode.byWordWrapping
   //created NSURL
    let requestURL = NSURL(string: URL_GET_TEAMS)
    //creating NSMutableURLRequest
    let request = NSMutableURLRequest(url: requestURL! as URL)
    //setting the method to post
    request.httpMethod = "POST"
    //creating a task to send the post request
    let task = URLSession.shared.dataTask(with: request as URLRequest){
        data, response, error in
        //exiting if there is some error
        if error != nil{
            print("error is \(error)")
            return;
        }
        //parsing the response
        do {
            //converting resonse to NSDictionary
            var teamJSON: NSDictionary!
            teamJSON =  try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
            //getting the JSON array teams from the response
            let teams: NSArray = teamJSON["contacts"] as! NSArray
            //looping through all the json objects in the array teams
            for i in 0 ..< teams.count{
                //getting the data at each index
                let teamId:String = (teams[i] as! NSDictionary)["title"] as! String!
                let teamName:String = (teams[i] as! NSDictionary) ["name"] as! String!
                //displaying the data
                //print("id -> ", teamId)
                //print("name -> ", teamName)
                //print("===================")
                //print("")
                self.myLabel = self.myLabel + "<font size='5'><b>" + teamId + "</font>:</b> " + "<font size='5'>" + teamName + "</font><br /><br />"
            }
        } catch {
            print(error)
        }
        DispatchQueue.main.async {
            let attrStr = try! NSAttributedString(data: self.myLabel.data(using: String.Encoding.unicode,allowLossyConversion: true)!, options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType], documentAttributes: nil)
            self.contactsLabel.attributedText = attrStr
            self.contactsLabel.sizeToFit()
        }
    }
    //executing the task
    task.resume()

    let attrStr = try! NSAttributedString(data: myLabel.data(using: String.Encoding.unicode,allowLossyConversion: true)!, options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType], documentAttributes: nil)
    contactsLabel.attributedText = attrStr
    contactsLabel.sizeToFit()
    getAddress()
}

此处的 getAddress 函数调用获取传入的数据并将其添加到标签中:

func getAddress() {
    //getting the JSON array teams from the response
    let address: NSArray = myAddress["mailing"] as! NSArray
    //looping through all the json objects in the array teams
    for i in 0 ..< address.count{

        //getting the data at each index
        let addrName:String = (address[i] as! NSDictionary)["name"] as! String!
        let addrAddr1:String = (address[i] as! NSDictionary) ["address1"] as! String!
        let addrAddr2:String = (address[i] as! NSDictionary)["address2"] as! String!
        let addrCity:String = (address[i] as! NSDictionary)["city"] as! String!
        let addrState:String = (address[i] as! NSDictionary)["state"] as! String!
        let addrZipcode:Int = (address[i] as! NSDictionary)["zipcode"] as! Int!

        let myCityStateZip : String = addrCity + ", " + addrState + " " + String(addrZipcode)

        let myName : String = addrName + "<br />" + addrAddr1 + "<br />" + addrAddr2

        let myDescription : String = "*All Correspondence for the Board / Assoc.<br /> should be directed to the following address:<br /><br />"

        self.myLabel = self.myLabel + "<b><font size='5'>" + myDescription + "</font></b>"
        self.myLabel = self.myLabel + "<font size='4'>" + myName + "</font>"
        self.myLabel = self.myLabel + "<font size='4'>" + myCityStateZip + "</font>"
        self.myLabel = self.myLabel + "<br /><br />"

        let attrStr = try! NSAttributedString(data: myLabel.data(using: String.Encoding.unicode,allowLossyConversion: true)!, options: [ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType], documentAttributes: nil)
        contactsLabel.attributedText = attrStr
        contactsLabel.sizeToFit()
    }
}

这是问题所在，第一次通过它可以完美地正确显示数据并按正确的顺序。如果您退出然后返回联系人页面，地址最终会出现在标签顶部，联系人如下。我似乎无法弄清楚为什么会发生这种情况。有任何想法吗？

Answer 1

我会将两个查找移动到前端(主视图 Controller 的 viewDidLoad 函数)并将它们作为值传递给第二个 Controller 。这样，您的第二个 Controller 只需关心格式化显示数据。