问题
I try to display data from a Firebase database into my tableView. The code worked using "Tabs View Controller", but for the purpose of the project I had to include a TableView in a classic ViewController.
Here is the code that should get the data from the database, and further include it in the tableview.
import UIKit
import Firebase
import FirebaseAuth
import FirebaseDatabase
class NewsfeedViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
var ref:DatabaseReference!,
posts = [eventStruct]()
@IBOutlet weak var tableview: UITableView!
struct eventStruct {
let title: String!
let date: String!
let location: String!
}
override func viewDidLoad() {
super.viewDidLoad()
loadNews()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
}
func loadNews() {
ref = Database.database().reference()
ref.child("events").queryOrderedByKey().observe(.childAdded, with: { (snapshot) in
if let valueDictionary = snapshot.value as? [AnyHashable:String]
{
let title = valueDictionary["Title"]
let location = valueDictionary["Location"]
let date = valueDictionary["Date"]
self.posts.insert(eventStruct(title: title, date: date, location: location), at: 0)
}
})
self.tableview.reloadData()
}
//Table View Content
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return posts.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
let label1 = cell.viewWithTag(1) as! UILabel
label1.text = posts[indexPath.row].title
let label2 = cell.viewWithTag(2) as! UILabel
label2.text = posts[indexPath.row].location
let label3 = cell.viewWithTag(3) as! UILabel
label3.text = posts[indexPath.row].date
return cell
}
}
I don't get any error but the data is not displayed in the tableView.
Previously I had to use override for each function that controls the tableview. If I don't have the override, I shouldn't call those functions somewhere in the code in order to have them working? Thank you.
回答1:
Completion block of observe
will call async and your self.tableview.reloadData()
will execute before that, so you need to reload the tableView
inside the completion block after you insert the object in array.
func loadNews() {
ref = Database.database().reference()
ref.child("events").queryOrderedByKey().observe(.childAdded, with: { (snapshot) in
if let valueDictionary = snapshot.value as? [AnyHashable:String]
{
let title = valueDictionary["Title"]
let location = valueDictionary["Location"]
let date = valueDictionary["Date"]
self.posts.insert(eventStruct(title: title, date: date, location: location), at: 0)
//Reload your tableView
self.tableview.reloadData()
}
})
}
Note: Also confirm once that your delegate
and datasource
of tableView is connected.
来源:https://stackoverflow.com/questions/44499210/ios-display-firebase-data-in-tableview