swift - SearchController - 我不希望在用户尚未开始输入时显示数据

Question

]我在我的应用程序中构建了一个 SearchViewController，它只用于搜索用户。

一切都很好，除了当我进入 View Controller 时，它会在我开始搜索之前显示 firebase 数据库中的每个用户？我希望表格 View 在我输入至少 2 个字母之前不显示结果。任何人都知道我可以实现这个吗？

这是我的代码:

class FollowUsersTableViewController: UITableViewController ,UISearchResultsUpdating, UISearchControllerDelegate{

//    @IBOutlet var followUsersTableView: UITableView!

func updateSearchResults(for searchController: UISearchController) {
    searchController.searchResultsController?.view.isHidden = false
    filterContent(searchText: self.searchController.searchBar.text!)
    self.tableView.reloadData()
}
private var viewIsHiddenObserver: NSKeyValueObservation?
let searchController = UISearchController(searchResultsController: nil)
var usersArray = [NSDictionary?]()
var filteredUsers = [NSDictionary?]()
var loggedInUser: User?

var databaseRef = Database.database().reference()

override func viewDidLoad() {
    super.viewDidLoad()
    //large title
    self.title = "Discover"
    if #available(iOS 11.0, *) {
        self.navigationController?.navigationBar.prefersLargeTitles = true
    } else {
        // Fallback on earlier versions
    }
    searchController.searchResultsUpdater = self
    searchController.dimsBackgroundDuringPresentation = false
    self.searchController.delegate = self;
    definesPresentationContext = true
    tableView.tableHeaderView = searchController.searchBar

    databaseRef.child("profile").queryOrdered(byChild: "username").observe(.childAdded, with: { (snapshot) in

        let key = snapshot.key
        let snapshot = snapshot.value as? NSDictionary
        snapshot?.setValue(key, forKey: "uid")

        if(key == self.loggedInUser?.uid) {
            print("Same as logged in user, so don't show!")
        } else {
            self.usersArray.append(snapshot)
            //insert the rows
            self.tableView.insertRows(at: [IndexPath(row:self.usersArray.count-1,section:0)], with: UITableViewRowAnimation.automatic)
            self.tableView.reloadData()
        } 
    }) { (error) in
        print(error.localizedDescription)
    }

    // Uncomment the following line to preserve selection between presentations
    // self.clearsSelectionOnViewWillAppear = false

    // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
    // self.navigationItem.rightBarButtonItem = self.editButtonItem
}

// MARK: - Table view data source
override func numberOfSections(in tableView: UITableView) -> Int {
    // #warning Incomplete implementation, return the number of sections
    return 1
}

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    // #warning Incomplete implementation, return the number of rows
    if searchController.isActive && searchController.searchBar.text != ""{
        return filteredUsers.count
    }

    return self.usersArray.count
}

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! FollowTableViewCell

    let user : NSDictionary?

    if searchController.isActive && searchController.searchBar.text != ""{
        user = filteredUsers[indexPath.row]
    }
    else
    {
        user = self.usersArray[indexPath.row]
    }

    cell.title?.text = user?["username"] as? String
    let url = URL(string: user?["photoURL"] as! String)!
    cell.userImage?.sd_setImage(with: url, placeholderImage: #imageLiteral(resourceName: "user_male"), options: .progressiveDownload, completed: nil)
    return cell
}

override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 50
}

override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let arr = self.searchController.isActive ? self.filteredUsers : self.usersArray
    self.performSegue(withIdentifier: "user", sender: arr[indexPath.row])
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    let dest = segue.destination as! UserProfileViewController
    let obj = sender as![String:Any]
    dest.selectedUser = obj
}

func filterContent(searchText:String)
{
    if searchText != ""{
        self.filteredUsers = self.usersArray.filter{ user in

            let username = user!["username"] as? String

            return(username?.lowercased().contains(searchText.lowercased()))! 
        }
    }
}

那么有人对我如何使这项工作有任何提示吗？ this is the error im getting

Answer 1

在您的 numberOfRowsInSection 中，您将返回 self.usersArray.count。如果您不显示所有结果，您可以简单地返回 0，并且不会显示任何结果。

如果你想在输入至少 2 个字符时显示搜索，那么使用 searchBar.text 的 count 属性

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    if searchController.isActive && searchController.searchBar.text != "" && searchController.searchBar.text.count >= 2 {
        return filteredUsers.count
    }

    return 0

}