我无法将在基于Swift IOS的聊天应用程序中从Firestore数据库中检索到的文档追加到“ messages”变量中,追加后,我在代码中配置了表格单元,如下所示,出现以下错误错误
Cannot convert value of type '[QueryDocumentSnapshot]' to expected argument type 'DocumentSnapshot'
代码
var messages: [DocumentSnapshot]! = []
func configuredatabase ()
{
db.collection("messages").document("hello").collection("newmessages").document("2").collection("hellos").document("K").collection("messages").addSnapshotListener { querySnapshot, error in
guard let documents = querySnapshot?.documents else {
print("Error fetching documents: \(error!)")
return
}
//here is the error
self.messages.append(documents)
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// Dequeue cell
let cell = self.clientTable .dequeueReusableCell(withIdentifier: "tableViewCell", for: indexPath)
// Unpack message from Firebase DataSnapshot
let messageSnapshot = self.messages![indexPath.row]
guard let message = messageSnapshot as? [String:String] else { return cell }
let name = message[Constants.MessageFields.name] ?? ""
if let imageURL = message[Constants.MessageFields.imageURL] {
if imageURL.hasPrefix("gs://") {
Storage.storage().reference(forURL: imageURL).getData(maxSize: INT64_MAX) {(data, error) in
if let error = error {
print("Error downloading: \(error)")
return
}
DispatchQueue.main.async {
cell.imageView?.image = UIImage.init(data: data!)
cell.setNeedsLayout()
}
}
} else if let URL = URL(string: imageURL), let data = try? Data(contentsOf: URL) {
cell.imageView?.image = UIImage.init(data: data)
}
cell.textLabel?.text = "sent by: \(name)"
} else {
let text = message[Constants.MessageFields.text] ?? ""
cell.textLabel?.text = name + ": " + text
cell.imageView?.image = UIImage(named: "ic_account_circle")
if let photoURL = message[Constants.MessageFields.photoURL], let URL = URL(string: photoURL),
let data = try? Data(contentsOf: URL) {
cell.imageView?.image = UIImage(data: data)
}
}
return cell
}