如何将Firebase iOS中的数据从TableViewController传递到另一个ViewController

Question

我正在开发应用程序，当我在搜索栏中搜索期间通过从Firebase数据库中检索用户名来查找用户时。我将所有用户的昵称放入一个数组中，并在点击文本与自动填充匹配用户昵称时，将其显示在tableView中。我能够做到。 但现在我试图显示用户配置文件页面，如果我搜索一个用户，我选择是在表视图名称然后点击他的昵称在tableView然后它打开另一个ViewController，并应显示用户选择的信息，但它只显示默认页面，没有关于所选用户的任何自定义信息。

我告诉你我当前的代码：

class UserTableViewController: UITableViewController, UISearchResultsUpdating { 

var userTab = [String]() 
var userEmpty = ["No user"] 
var filteredUsers = [String]() 

var searchController: UISearchController! 
var resultsController = UITableViewController() 

var name: String! 

var ref: DatabaseReference! 
var dictDetails: [String:AnyObject]? 

override func viewDidLoad() { 
    super.viewDidLoad() 

    self.resultsController.tableView.dataSource = self 
    self.resultsController.tableView.delegate = self 

    ref = Database.database().reference() 

    ref.child("users").queryOrdered(byChild: "pseudo").observeSingleEvent(of: .value, with: { (snapshot) in 
     self.userTab = [] 
     if (snapshot.value is NSNull) { 
      print("No data found") 
     } else { 
      for child in snapshot.children { 
       let userSnap = child as! DataSnapshot 
       let uid = userSnap.key 
       let userDict = userSnap.value as! [String: AnyObject] 
       let pseudo = userDict["pseudo"] as! String 
       let total = snapshot.childrenCount 
       self.userTab.append(pseudo) 
       self.resultsController.tableView.reloadData() 
       continue 
      } 
     } 
    }) 

    self.searchController = UISearchController(searchResultsController: self.resultsController) 
    self.tableView.tableHeaderView = self.searchController.searchBar 
    self.searchController.searchResultsUpdater = self 
    self.searchController.dimsBackgroundDuringPresentation = false 
    self.definesPresentationContext = true 
} 

func updateSearchResults(for searchController: UISearchController) { 
    self.filteredUsers = self.userTab.filter { (user:String) -> Bool in 
     if user.lowercased().contains(self.searchController.searchBar.text!.lowercased()) { 
      return true 
     } else { 
      return false 
     } 
    } 
    self.resultsController.tableView.reloadData() 
} 

override func prepare(for segue: UIStoryboardSegue, sender: Any?) { 
    if segue.identifier == "userProfil" { 
     if let indexPath = self.tableView.indexPathForSelectedRow { 
      let data = userTab[indexPath.row] as! [String: AnyObject] 
      let pseudo = data["pseudo"] as? String 
      let controller = segue.destination as! UserViewController 
      controller.pseudo = pseudo! 
     } 
    } 
} 

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 
    if tableView == self.tableView { 
     return self.userTab.count 
    } else { 
     return self.filteredUsers.count 
    } 
} 

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { 
    let cell = UITableViewCell() 
    if tableView == self.tableView { 
     cell.textLabel?.text = self.userTab[indexPath.row] 
    } else { 
     cell.textLabel?.text = self.filteredUsers[indexPath.row] 
    } 
    return cell 
} 

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { 
    performSegue(withIdentifier: "userProfil", sender: nil) 
} 
} 

而对于其他视图控制器：

class UserViewController: UIViewController { 
@IBOutlet weak var name: UILabel! 
var pseudo: String = "" 
var dictionary: [String:AnyObject]? 
var ref: DatabaseReference! 

override func viewDidLoad() { 
    super.viewDidLoad() 
    ref = Database.database().reference() 
    ref.child("users").queryOrdered(byChild: pseudo).observeSingleEvent(of: .value, with: { (snapshot) in 
     if let dictionary = snapshot.value as? [String: AnyObject] { 
      self.name.text = dictionary["pseudo"] as? String 
     } 
    }) 
} 
} 

我怎么能这样做？

Answer 1

我自己解决了这个问题，我发布代码，如果它可以帮助别人。

我告诉你我当前的代码（第一个视图控制器是UserTableViewController）：

class UserTableViewController: UITableViewController, UISearchResultsUpdating { 

var userTab = [String]() 
var userEmpty = ["No user"] 
var filteredUsers = [String]() 

var searchController: UISearchController! 
var resultsController = UITableViewController() 

var name: String! 
var ref: DatabaseReference! 

override func viewDidLoad() { 
    super.viewDidLoad() 

    self.resultsController.tableView.dataSource = self 
    self.resultsController.tableView.delegate = self 

    ref = Database.database().reference() 

    ref.child("users").queryOrdered(byChild: "pseudo").observeSingleEvent(of: .value, with: { (snapshot) in 
     self.userTab = [] 
     if (snapshot.value is NSNull) { 
      print("No data found") 
     } else { 
      for child in snapshot.children { 
       let userSnap = child as! DataSnapshot 
       let uid = userSnap.key 
       let userDict = userSnap.value as! [String: AnyObject] 
       let pseudo = userDict["pseudo"] as! String 
       let total = snapshot.childrenCount 
       self.userTab.append(pseudo) 
       self.resultsController.tableView.reloadData() 
       continue 
      } 
     } 
    }) 

    self.searchController = UISearchController(searchResultsController: self.resultsController) 
    self.tableView.tableHeaderView = self.searchController.searchBar 
    self.searchController.searchResultsUpdater = self 
    self.searchController.dimsBackgroundDuringPresentation = false 
    self.definesPresentationContext = true 
} 

func updateSearchResults(for searchController: UISearchController) { 
    self.filteredUsers = self.userTab.filter { (user:String) -> Bool in 
     if user.lowercased().contains(self.searchController.searchBar.text!.lowercased()) { 
      return true 
     } else { 
      return false 
     } 
    } 
    self.resultsController.tableView.reloadData() 
} 

// I change the content of this function 
override func prepare(for segue: UIStoryboardSegue, sender: Any?) { 
    if segue.identifier == "userProfil" { 
     let userViewController = segue.destination as! UserViewController 
     userViewController.pseudo = self.name! // "name" is a String variable declared at the beginning, "pseudo" is a variable declared in the UserViewController 
    } 
} 

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 
    if tableView == self.tableView { 
     return self.userTab.count 
    } else { 
     return self.filteredUsers.count 
    } 
} 

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { 
    let cell = UITableViewCell() 
    if tableView == self.tableView { 
     cell.textLabel?.text = self.userTab[indexPath.row] 
    } else { 
     cell.textLabel?.text = self.filteredUsers[indexPath.row] 
    } 
    return cell 
} 

// This function is the most important because after search a user in search bar, it display it in table view cell then you choose it so you go the UserViewController where you can see the username write on this user profile page, you got to write the performSegue at the end of this function if not it can't work because if you put the performSegue at the beginning it won't find the right username because the prepare for segue function will call before and we don't want our "name" variable is nil 
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { 
    let post = filteredUsers[indexPath.row] as! String 
    self.name = post 
    print("name : \(name!)") // You can see in the console the name of the user you choose 
    performSegue(withIdentifier: "userProfil", sender: nil) 
} 
} 

而对于其他视图控制器（UserViewController）：

class UserViewController: UIViewController { 
@IBOutlet weak var name: UILabel! 
var pseudo = "" 

override func viewDidLoad() { 
    super.viewDidLoad() 

    name.text = pseudo // Here name is a Label, so I put the "pseudo" variable for display it in the "name" Label and it can show the right nickname of user you choose in the search bar 
} 
} 

希望它可以帮助别人。 现在我试图在同一页面显示他的用户配置文件图像。