我有一个tableViewController，它有一个登录用户与他/她选择的任何用户有过的消息列表。单击单元格时，它应该转到视图控制器，允许登录用户与任何用户聊天。我已经设置了一个覆盖segue：
var userpicuid: String?
var username: String?
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let message = messages[indexPath.row]
if message.ReceiverId != self.loggedInUserUid {
var newVariable = message.ReceiverId
if self.userpicuid == newVariable {
let ref = FIRDatabase.database().reference().child("users").child(userpicuid!)
ref.observeSingleEvent(of: .value, with: { (snapshot)
in
if let dictionary = snapshot.value as? [String: AnyObject]{
for post in dictionary {
let messages = post.value as! [String: AnyObject]
for (id, value) in messages {
self.username = messages["username"] as? String
}}}})}} else if message.senderId != self.loggedInUserUid {
let newVariable = message.senderId
if self.userpicuid == newVariable {
let ref = FIRDatabase.database().reference().child("users").child(userpicuid!)
ref.observeSingleEvent(of: .value, with: { (snapshot)
in
if let dictionary = snapshot.value as? [String: AnyObject]{
for post in dictionary {
let messages = post.value as! [String: AnyObject]
for (id, value) in messages {
self.username = messages["username"] as? String
}}}})}
}
performSegue(withIdentifier: "MessageNow", sender: self.userpicuid)
}
override public func prepare(for segue: UIStoryboardSegue, sender: Any?) {
guard segue.identifier == "MessageNow", let chatVc = segue.destination as? SendMessageViewController else {
return
}
chatVc.senderId = self.loggedInUser?.uid
chatVc.receiverData = sender as AnyObject
chatVc.senderDisplayName = self.userpicuid
chatVc.username = self.username
}
在目标视图控制器中，这是设置：
var receiverData: AnyObject?
override func viewDidLoad() {
super.viewDidLoad()
self.senderId = FIRAuth.auth()?.currentUser?.uid
let receiverId = receiverData as! String
let receiverIdFive = String(receiverId.characters.prefix(5))
let senderIdFive = String(senderId.characters.prefix(5))
if (senderIdFive > receiverIdFive)
{
self.convoId = senderIdFive + receiverIdFive
}
else
{
self.convoId = receiverIdFive + senderIdFive
}}
我收到错误无法将类型为“Lit_Swap.MessageTableViewCell”（0x1091d0f10）的值转换为“NSString”（0x10b153c60）。因为发件人显然是一个tableviewcell，我将如何设置发件人，这样我就可以点击单元格并进入聊天控制器。
答案 0 :(得分：0)
有很多方法可以在视图之间移动数据，一种是segue，而且还有很多segue选项。
这里使用的是RepresentObject属性
假设我们有一个带有textField的视图控制器和一个触发secondSheetController动作的按钮
class ViewController: NSViewController {
@IBOutlet weak var sourceTextField: UITextField!
override func viewDidLoad() {
super.viewDidLoad()
}
override func prepare(for segue: NSStoryboardSegue, sender: Any?) {
let second = segue.destinationController as! SecondController
second.representedObject = self.myTextField.text
}
}
而viewController我们是
class SecondController: NSViewController {
@IBOutlet weak var targetTextField: NSTextField!
override func viewDidLoad() {
super.viewDidLoad()
}
override func viewWillAppear() {
self.targetTextField.text = self.representedObject as! String
}
}
另外，为了解决发件人是String的问题而且我们不想使用representObject属性，对String的赋值将是一个解决方案。
chatVc.receiverData = sender as! String
作为第三个选项，可以直接设置SecondController中的任何类变量
class SecondController: NSViewController {
var option1 = ""
var option2 = ""
然后从第一个视图控制器
secondController.option1 = "look kids, Parliament, Big Ben"
secondController.option2 = "Don't call me Shirley"
答案 1 :(得分：0)
如果您使用的是UINavigatorcontroll。你可以尝试这个解决方案。
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let selectedConversation = conversationArray[indexPath.row]
showConversationMessages(conversation: selectedConversation)
}
func showConversationMessages(conversation: ConversationItem){
let vc = storyboard?.instantiateViewController(withIdentifier: "MessagesViewController") as! MessagesVC
vc.receiverId = conversation.idMessagePartner
vc.receiverToken = conversation.receiverToken
vc.receiverUserName = conversation.userDisplayName
navigationController?.pushViewController(vc, animated: true)
}
ConversationItem是我的班级，用于保存我需要的数据。
然后你可以在你的第二个控制器中使用变量，我在我的例子中命名为MessageVC。
class MessagesVC: UIViewController, UITableViewDelegate, UITableViewDataSource, UITextViewDelegate {
private let TAG = "MessagesVC"
var receiverId: Int64 = 0
var receiverToken: String = ""
var receiverUserName: String = ""
....
我从未真正与override func prepare(for segue: NSStoryboardSegue, sender: Any?)合作，但我确实看到很多人都遇到过问题。