ios - 当我想在 UICollectionview 中添加一个单元格时，它会出现两个 - Swift 3

Question

我的应用程序有问题。当我想在 UICollectionViewController 中添加一个 UICollectionViewcell 时，它出现了两个单元格而不是一个。它们显示完全相同。还有其他人遇到同样的问题吗？我试过用谷歌搜索一下解决方案，但找不到任何东西......我正在用 Swift 3 编写。

这是我的代码:

    import UIKit
    import Firebase
    import MapKit
    import CoreLocation

    class ProfileController: UICollectionViewController, UICollectionViewDelegateFlowLayout {

    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(.childAdded, 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)


}

func ObservePosition() {

    let ref = FIRDatabase.database().reference().child("position")
    ref.observe(.childAdded, with: { (snapshot) in

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


        return FedCell


    }

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




}

class FeedCell: UICollectionViewCell, UICollectionViewDelegateFlowLayout, CLLocationManagerDelegate, MKMapViewDelegate {

    var user = [User]()

    var positions = [Position]()


    var wiindow: UIWindow?
    var mapView: MKMapView?
    let locationManager = CLLocationManager()

    let distanceSpan: Double = 500

    var locationData: CLLocation!

        override init(frame: CGRect) {
            super.init(frame: frame)

            setupViews()
        }

        required init?(coder aDecoder: NSCoder) {
            fatalError("init(coder:) has not been implemented")
        }

        let nameLabel: UILabel = {
            let label = UILabel()
            label.font = UIFont.boldSystemFont(ofSize: 14)
            label.translatesAutoresizingMaskIntoConstraints = false
            return label
        }()

        let profileImag

eView: UIImageView = {
        let imageView = UIImageView()
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.layer.cornerRadius = 22
        imageView.layer.masksToBounds = true
        imageView.backgroundColor = UIColor.blue
        return imageView
    }()

let separatorView: UIView = {
    let view = UIView()
    view.backgroundColor = UIColor(red: 192/255, green: 192/255, blue: 192/255, alpha: 1)
    view.translatesAutoresizingMaskIntoConstraints = false
    return view
}()


func setupViews() {

    addSubview(profileImageView)
    addSubview(nameLabel)
    addSubview(separatorView)


    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-10-[v0(44)]-10-[v1]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": profileImageView, "v1": nameLabel]))

    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-10-[v0(44)]", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": profileImageView]))

    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|[v0]-385-|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": nameLabel]))

    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|[v0]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": separatorView]))

    addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:[v0(1)]|", options: NSLayoutFormatOptions(), metrics: nil, views: ["v0": separatorView]))

    self.wiindow = UIWindow(frame: UIScreen.main.bounds)
    self.backgroundColor = UIColor(white: 0.95, alpha: 1)

    self.mapView = MKMapView(frame: CGRect(x: 0, y: 70, width: (self.wiindow?.frame.width)!, height: 355))
    self.addSubview(self.mapView!)

    self.locationManager.delegate = self
    self.locationManager.desiredAccuracy = kCLLocationAccuracyBest
    self.locationManager.requestWhenInUseAuthorization()
    self.locationManager.startUpdatingLocation()
    self.mapView!.showsUserLocation = true

    self.mapView!.isZoomEnabled = false
    self.mapView!.isScrollEnabled = false
    self.mapView!.isUserInteractionEnabled = false


}

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)
        mapView.showsUserLocation = true
    }
}

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

    let ref = FIRDatabase.database().reference().child("position")
    ref.observe(.childAdded, with: { (locationSnap) in


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


            self.locationData = locations.last

            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

您有两个 observePosition 函数。在第二个中，您两次添加位置。删除第二个 observePosition 函数来修复它。