Question

我正在尝试更新的ProductViewController上有一个名为 idLabel 的标签。以下是发送信息的VC。有一次我按下 playThis 按钮时文本更新，标签会从股票标签文本变为零，所以我知道发生了什么事情，但现在它在{{1}它只显示没有。如何让它在接收端显示文字？

这是发送VC：

viewDidLoad

以下是import UIKit import Firebase import FirebaseAuth import FirebaseDatabase import FirebaseStorage class ListViewController: UIViewController, UITableViewDelegate, UITableViewDataSource { @IBOutlet weak var tableViewProducts: UITableView! var delegate: ListViewController? var ref:DatabaseReference? var databaseHandle: DatabaseHandle? var postData = [String]() override func viewDidLoad() { super.viewDidLoad() ref = Database.database().reference() databaseHandle = ref?.child("0").observe(.childAdded, with: { (snapShot) in let post = snapShot.value as? String if let actualPost = post { self.postData.append(actualPost) self.tableViewProducts.reloadData() } }) } func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { print(postData) return postData.count } //This places the text on the ViewControllerTableViewCell which does show up func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { let cell = tableView.dequeueReusableCell(withIdentifier: "cell") cell?.textLabel?.text = postData[indexPath.row] cell?.textLabel?.textColor = UIColor.white return cell! } func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) { performSegue(withIdentifier: "showDetails", sender: self) } //This code is what sends the text data elswhere override func prepare(for segue: UIStoryboardSegue, sender: Any?) { if let destination = segue.destination as? ProductViewController { destination.updater?.id = postData[(tableViewProducts.indexPathForSelectedRow?.row)!] } } }：

ProductViewController

Answer 1

如果您只是计划传递id而不是对象，那么请使用一个简单的变量。

您准备segue的代码将成为

destination.variable = id_to_pass.

现在您在ProductViewController中获得了id，您可以在viewdidload

中更新它

Answer 2

ListViewController
中updater的设置值出现问题

您正在将值设置为尚未初始化的对象。

//This code is what sends the text data elswhere
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let destination = segue.destination as? ProductViewController {
        destination.updater?.id = postData[(tableViewProducts.indexPathForSelectedRow?.row)!]
    }
}

按以下方式更新代码

//This code is what sends the text data elswhere
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if let destination = segue.destination as? ProductViewController,
        let index = tableViewProducts.indexPathForSelectedRow?.row {

        // Check whether postData array count is greater than index
        let updaterId = postData.count > index ? postData[index] : ""

        // Initialize "productsList" instance and assign the id value and sent this object to next view controller
        var updater = productsList()
        updater.id = updaterId
        destination.updater = updater
    }
}

无法获取标签文字以更新swift

2 个答案: