设置一个属性以更新VC swift上显示的信息

问题描述

我有2个视图控制器，VC1在我的应用程序中显示所有用户的基本信息，当您在某个单元格中按更多信息"按钮时，它会选择一个新的VC，该VC显示用户在您所使用的单元格中的完整个人资料先前按下.

I have 2 view controllers, VC1 displays all the users on my apps basic info, when you press a more info button in a certain cell it segues to a new VC that displays the users full profile that was in the cell that you previously pressed.

在帮助下，我可以进行所有工作，除了如何在VC2上显示结果.我正在尝试在VC2中设置属性.我也尝试过

With help I have everything working except for how to display the results on VC2. I am trying to set a property in the VC2. I also tried for

此代码未返回任何错误，但在VC2上什么也不显示.

This code is returning no errors but displays nothing on the VC2.

我尝试设置，获取willSet，所有内容都无法破解:

I've tried set, get willSet, everything and can't crack it:

var userToShowDetail: PFUser? {
    willSet {
        self.configureView()
    }
}

func configureView() {
    // Update the user interface for the detail item.
    if let userToShowDetail: PFUser = self.userToShowDetail {
        if let label = self.userName {
            userName.text = userToShowDetail["name"] as! String?

        }
    }
}

override func viewDidLoad() {

我尝试了这个，但是它只返回一个空的VC:

I tried this one but it returns nothing but an empty VC:

var userToShowDetail: PFUser?

override func viewDidLoad() {
    super.viewDidLoad()

    if let appUsers = userToShowDetail as PFUser? {

    self.userName.text = appUsers["name"] as? String

    self.userInstrument.text = appUsers["instrument"] as? String

    self.userAge.text = appUsers["age"] as? String

    self.userProfile.file = appUsers["image"] as? PFFile

    self.userProfile.layer.cornerRadius = self.userProfile.frame.size.width/2

    self.userProfile.clipsToBounds = true

    self.userProfile.loadInBackground()
    }

我已经研究了didSet和willSet，但是我仍然茫然.任何帮助将不胜感激.有人可以给我指向教程或建议我，下一步是什么.

I have researched didSet and willSet but I am still at a loss. Any help would be greatly appreciated. What is the next step can someone point me to a tutorial or advise me please.

willSet和DidSet目的 Apple属性

View Controller 1 segue:

View Controller 1 segue:

override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
if segue.identifier == "userProfileDetailsSegue" {
//get the index path for the row that was selected
let indexPath = self.resultsPageTableView.indexPathForSelectedRow!
//get the PFUser object for that particular row
let userToShow = self.appUsers[indexPath.row]
//create your new view controller
let newVc = segue.destinationViewController as! UserProfileDetailsViewController
//assign the new vc's property to your object
newVc.userToShowDetail = userToShow
}
}

推荐答案

当您不熟悉Swift时，这是一个常见错误.
-当您选择VC2并将值传递给"userToShowDetail"时.将调用"userToShowDetail"的"didSet"方法.
-不幸的是，此时VC2的视图仍然为零.因此您会收到此错误.
-解决方法很简单，请添加?"在"didSet"功能中的每个视图之后.并且不要忘记在VC2的viewDidload中调用"didSet"功能.

This is a common mistake when you are newer to swift.
- When you segue to VC2, and pass a value to "userToShowDetail".The "didSet" method of "userToShowDetail" will be called.
- Unfortunately, at this point, your VC2's views are still nil.So you will get this error.
- The solution is simple,add a "?" after each view in your "didSet" func.And don't forget to call "didSet" func in VC2's viewDidload.

func configureView() {
if let userToShowDetail: PFUser = self.userToShowDetail {
    if let label == self.userName? {//add "?" to VC2's subviews 
        userName?.text = userToShowDetail["name"] as! String?//add "?" to VC2's subviews 
    }
  }
}

override func viewDidLoad() {
  super.viewDidLoad()
  configureView()//call mothed in didSet()
  // other thing you need to do
}

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