【发布时间】:2019-08-01 19:53:40
【问题描述】:
我是 Swift 的新手。我有一个到 websocket 的连接(使用 Starscream),我正在等待以这种方法接收文本或事件:
func websocketDidReceiveMessage(socket: WebSocketClient, text: String)
当我得到一个事件(只是 ID)时,我从另一个视图控制器触发 func fetchInfoAboutInvitations(text: String);这个func指的是http请求(从服务器获取所有关于事件的信息),这个func带有completion:
func gettingInfoAboutInvitationAfterSocket(invitationId: String, completion: @escaping (Invitations) -> Void)
然后我回到 fetchInfoAboutInvitations 函数,以尝试:
info.getInfoAboutInvitationAfterSocket(invitationId: text)
{ (invitation) in
print("some inv: \(invitation)") // -- here i got data
self.arrList.append(invitation)
DispatchQueue.main.async {
self.tableViewController.reloadData()
}
关于这个:
var arrList = [Invitations]() {
didSet {
print("arrList: \(arrList)")
}
}
我的数据有一个打印输出,但 tableview 是空的。如果我重新运行我的应用程序,我的表格视图将不为空。另一个功能工作正常:
func getCurrentEvent() {
currentInvitations.getCurrentInvitations { (value) in
print("currentInv value get CURINVI: \(value)")
self.arrList.append(value)
DispatchQueue.main.async {
self.tableViewController.reloadData()
}
}
}
我的 viewDidLoad:
override func viewDidLoad() {
super.viewDidLoad()
tableViewController.delegate = self
tableViewController.dataSource = self
getCurrentEvent()
}
我猜我无法在 var arrList = Invitations 中追加数据的原因是因为我在 viewDidLoad 中没有 func fetchInfoAboutInvitations(text: String),但我无法添加它,因为它是一个闭包
更新:
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return arrList.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = tableViewController.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as? EventControllerCell {
cell.nameLabel.text = arrList[indexPath.row].id
return cell
}
return UITableViewCell()
}
更新#2,添加一些细节: 这里我从 websocket(server) 获取事件
func websocketDidReceiveMessage(socket: WebSocketClient, text: String) {
print("websocketDidReceiveMessage text: \(text)")
do {
let welcome = try? JSONDecoder().decode(Welcome.self, from: text.data(using: .utf8)!)
print("welcome: \(String(describing: welcome))")
print("welcome dataDataId: \(String(describing: welcome?.data.data.objectID))")
print("welcome eventType: \(String(describing: welcome?.data.eventType))")
if let invitationId = welcome?.data.data.objectID {
let event = EventController()
event.fetchInfoAboutInvitations(text: invitationId)
}
}
然后我触发:
func fetchInfoAboutInvitations(text: String) {
let info = InfoAboutInvitation()
info.getInfoAboutInvitationAfterSocket(invitationId: text) { (invitation) in
print("some inv: \(invitation)")
self.arrList.append(invitation)
DispatchQueue.main.async {
self.tableViewController.reloadData()
}
}
}
完成的请求:
func getInfoAboutInvitationAfterSocket (invitationId: String, completion: @escaping (Invitations) -> Void) {
guard var urlComp = URLComponents(string: "") else {return}
urlComp.path = ""
guard let url = urlComp.url else { return }
var request = URLRequest(url: url)
request.httpMethod = "GET"
request.setValue("a")
request.addValue("", forHTTPHeaderField: "")
let task = URLSession.shared.dataTask(with: request) { (data, response, error) in
if error != nil {
print("URLSession error")
print(error!)
}
guard let data = data else {
print("data is empty")
return
}
do {
let getData = try! JSONDecoder().decode(Invite.self, from: data)
let invitionData = Invitations(id: getData.id, initiator: getData.initiator, receiver: getData.receiver, group: getData.group, created: nil, status: getData.status, replieadAt: getData.replieadAt)
print("info about invitationData (infAbout): \(invitionData)")
completion(invitionData)
} catch let err {
print(err)
}
}
task.resume()
}
如果问题不清楚,有人可以告诉我如何用另一种方式实现这一点吗?我不知道如何将它与 delegates\protocols 一起使用(以及如何实现它)。
我在另一台 PC 上运行该应用程序,现在我在 tableView 中有 null,当关闭工作时:
func fetchInfoAboutInvitations(text: String) {
info.getInfoAboutInvitationAfterSocket(invitationId: text) { (invitation) in
print("some inv: \(invitation)")
self.arrList.append(invitation)
DispatchQueue.main.async {
self.tableViewController.reloadData() // - here I got nil
}
}
}
【问题讨论】: