ios - Swift - 当我添加新单元格时，所有单元格都会发生变化(需要单个单元格)

Question

我目前正在开发一个项目，需要一些帮助。我的应用已连接到 Firebase，并且它是用 Swift 编码的。

我的问题:

当我按下“共享”按钮时，它是否会将坐标发送到 Firebase(经度和纬度)。一个单元格添加到我的 UICollectionViewController 中并从 Firebase 检索坐标。因此它显示在 UICollectionViewCell 的 map 上。到目前为止，一切都很好。但是，当我从另一个位置再次按下“共享”按钮时，它会再次添加另一个单元格，但这一次它将所有单元格上的位置更改为最新位置。

即使我使用其他用户登录，它也会发生变化。我怀疑我必须将 func locationManager(_ manager: CLLocationManager, didUpdateLocationslocations: [CLLocation]) 放入

override func collectionView(_ collectionView: UICollectionView, cellForItemAt 

indexPath: IndexPath) -> UICollectionViewCell 

希望大家能够理解这一点。要把这件事做好有点难，这件事很新鲜。

PS:代码可能不是最好的，但我只是想获得我所要求的帮助......

这是我的代码

import UIKit
import Firebase
import MapKit
import CoreLocation

class ProfileController: UICollectionViewController, UICollectionViewDelegateFlow

Layout {

    let cellId = "cellId"



var users = [User]()

var positions = [Position]()



override func viewDidLoad() {
    super.viewDidLoad()

    navigationItem.leftBarButtonItem = UIBarButtonItem(title: "Logout", style: .plain, target: self, action: #selector(handleLogout))

    navigationItem.title = "Profile"

    collectionView?.backgroundColor = UIColor(white: 0.95, alpha: 1)
    collectionView?.alwaysBounceVertical = true
    collectionView?.register(FeedCell.self, forCellWithReuseIdentifier: cellId)

    observePosition()




    }

    func handleLogout() {

        do {
            try FIRAuth.auth()?.signOut()
        } catch let logoutError {
            print(logoutError)
        }

        let loginContoller = LoginController()
        present(loginContoller, animated: true, completion: nil)

    }


    func observePosition() {

        let ref = FIRDatabase.database().reference().child("position")
        ref.observe(.child

Added, with: { (snapshot) in

        if let dictionary = snapshot.value as? [String: AnyObject] {
            let position = Position()
            position.setValuesForKeys(dictionary)
            self.positions.append(position)

            DispatchQueue.main.async(execute: {
                self.collectionView!.reloadData()
            })

    }

    }, withCancel: nil)

}



override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return positions.count
}



override func collectionView(_ collectionView: UICollectionView, cellForItemAt 

indexPath: IndexPath) -> UICollectionViewCell {

        let FedCell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! FeedCell

        let position = positions[(indexPath as NSIndexPath).row]


        if let fromId = position.fromId { //To get the username 
            let ref = FIRDatabase.database().reference().child("users").child(fromId) //get username
            ref.observeSingleEvent(of: .value, with: { (snapshot) in


                if let dictionary = snapshot.value as? [String: AnyObject] {

                    FedCell.nameLabel.text = dictionary["name"] as? String //get username 


                }


            }, withCancel: nil)

        }


        return FedCell


}




    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        return CGSize(width: view.frame.width, height: 450)
    }

还有我的手机

class FeedCell: UICollectionViewCell, UICollectionViewDelegateFlowLayout, CLLocationManagerDelegate, MKMapViewDelegate {



    var user = [User]()

    var positions = [Position]()


 private func locationManager(manager: CLLocationManager, didUpdateToLocation newLocation: CLLocation, fromLocation oldLocation: CLLocation) {
        if let mapView = self.mapView {
             let region = MKCoordinateRegionMakeWithDistance(newLocation.coordinate, self.distanceSpan, self.distanceSpan)
        mapView.setRegion(region, animated: true)

        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

        let ref = FIRDatabase.database().reference().child("position")
        ref.obse

rve(.childAdded, with: { (locationSnap) in





        if let locationDict = locationSnap.value as? [String: AnyObject] {



            guard let lat = locationDict["latitude"] as? CLLocationDegrees,
                let long = locationDict["longitude"] as? CLLocationDegrees else { return }



            let center = CLLocationCoordinate2D(latitude: lat, longitude: long)
            let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))

            let locationPin = CLLocationCoordinate2D(latitude: lat, longitude: long)
            let annotation = MKPointAnnotation()
            annotation.coordinate = locationPin


            self.mapView!.setRegion(region, animated: true)
            self.mapView!.showsUserLocation = false
            self.mapView!.addAnnotation(annotation)
            self.mapView!.showAnnotations([annotation], animated: true)
            self.locationManager.stopUpdatingLocation()



        }

    })


   }


}

Answer 1

这是因为单元的可重复使用性。您需要以与设置名称相同的方法来设置位置，但请记住它们不应被新值覆盖。