swift – 如何将firebase数据库数据作为UICollection View的数据源？

如果您想提供更完整的数据库截图(只显示键和数据类型),我很乐意修改此代码.

由于我不知道你如何更新你的集合视图,我已经做了它所以它返回一个字典,其中键是类别,值是该类别的bussinesses数组.如果您在集合视图中使用部分,这应该是一种简单的格式.

关于typealias FirebaseRootDictionary,可能需要修改它,因为我猜测你的数据库模式是什么.

如果您对此代码有任何疑问或问题,请在下面添加评论,我会尝试修复它.

所以要获取你的数据：

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view,typically from a nib.

    Business.getBusinesses { (businesses) in

        print(businesses)
    }
}

然后在该闭包内部更新集合视图.

import Foundation
import Firebase

final class Business : NSObject {

    typealias FirebaseRootDictionary = Dictionary<String,Dictionary<String,String>>>

    var name: String

    var category: String

    var email: String

    var imageUrl: String

    override var description: String {

        return "Business(name: \"\(name)\",category: \"\(category)\",email: \"\(email)\",imageUrl: \"\(imageUrl)\")"
    }

    init(name:String,category:String,email:String,imageUrl:String) {

        self.name = name

        self.category = category

        self.email = email

        self.imageUrl = imageUrl
    }

    class func getBusinesses(completionHandler:@escaping (_ businesses: BusinessesDictionary)->()) { // -> [Business]

        let ref = FIRDatabase.database().reference().child("BusinessCategories")

        var businesses = BusinessesDictionary()

        ref.observeSingleEvent(of: .value,with: { (snapshot) in

            guard let value = snapshot.value as? FirebaseRootDictionary else { return }

            let categories = value.keys.sorted()

            var arr = [Business]() // Array of businesses for category

            for cat in categories {

                guard let data = value[cat] else { continue }

                let businessKeys = data.keys.sorted()

                for key in businessKeys {

                    guard let businessData = data[key] else { continue }

                    guard let name = businessData["BusinessName"],let category = businessData["Category"],let email = businessData["email"],let imageUrl = businessData["imageUrl"] else { continue }

                    let business = Business(name: name,category: category,email: email,imageUrl: imageUrl)

                    arr.append(business)
                }

                businesses[cat] = arr

                arr.removeAll()
            }

            completionHandler(businesses)
        })
    }
}

编辑：

因此,对于视图,您有一个tableview,每个部分/类别有一个单元格.单元格具有集合视图,该集合视图具有带有图像视图和标签的集合视图单元格.所以我在这里有一个表视图控制器来处理所有这些.

import UIKit

typealias BusinessesDictionary = Dictionary<String,[Business]> // I have moved this typealias to here instead of inside the Business Model.

class TableViewController: UITableViewController {

    var tableData = BusinessesDictionary()

    override func viewDidLoad() {
        super.viewDidLoad()

        self.tableView.register(CategoryCell.self,forCellReuseIdentifier: "cell")

        self.tableView.allowsSelection = false

        Business.get { (businesses) in

            self.tableData = businesses

            self.tableView.reloadData()
        }
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // dispose of any resources that can be recreated.
    }

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {

        return self.tableData.keys.count
    }

    override func tableView(_ tableView: UITableView,titleForHeaderInSection section: Int) -> String? {

        let category = self.tableData.keys.sorted()[section]

        return category
    }

    override func tableView(_ tableView: UITableView,numberOfRowsInSection section: Int) -> Int {

        return 1
    }

    override func tableView(_ tableView: UITableView,cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        guard let cell = tableView.dequeueReusableCell(withIdentifier: "cell",for: indexPath) as? CategoryCell else { return UITableViewCell() }

        // Configure the cell...

        let category = self.tableData.keys.sorted()[indexPath.section]

        guard let businesses = self.tableData[category] else { return UITableViewCell() }

        cell.businesses = businesses

        return cell
    }

    override func tableView(_ tableView: UITableView,heightForRowAt indexPath: IndexPath) -> CGFloat {

        return 120
    }
}

表视图单元格文件.

class CategoryCell: UITableViewCell,UICollectionViewDelegate,UICollectionViewDataSource {

    var collectionView: UICollectionView!

    var businesses = [Business]()

    override func layoutSubviews() {

        let layout: UICollectionViewFlowLayout = UICollectionViewFlowLayout()

        layout.sectionInset = UIEdgeInsets(top: 0,left: 0,bottom: 0,right: 0) // You may wan to change this as this is the spacing between cells

        layout.itemSize = CGSize(width: 100,height: 120) // You may wan to change this as this is the cell size

        layout.scrollDirection = .horizontal

        collectionView = UICollectionView(frame: self.bounds,collectionViewLayout: layout)

        collectionView.topAnchor.constraint(equalTo: self.topAnchor)

        collectionView.leftAnchor.constraint(equalTo: self.leftAnchor)

        collectionView.rightAnchor.constraint(equalTo: self.rightAnchor)

        collectionView.bottomAnchor.constraint(equalTo: self.bottomAnchor)

        collectionView.dataSource = self

        collectionView.delegate = self

        collectionView.register(BusinessCell.self,forCellWithReuseIdentifier: "businessCell")

        collectionView.backgroundColor = .white

        self.addSubview(collectionView)
    }

    func collectionView(_ collectionView: UICollectionView,numberOfItemsInSection section: Int) -> Int {

        return businesses.count
    }

    func numberOfSections(in collectionView: UICollectionView) -> Int {

        return 1
    }

    func collectionView(_ collectionView: UICollectionView,cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        guard let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "businessCell",for: indexPath) as? BusinessCell else { return UICollectionViewCell() }

        // Configure the cell

        let business = self.businesses[indexPath.row]

        cell.nameLabel.text = business.name

        cell.imageView.image = UIImage(named: business.imageUrl)

        return cell
    }
}

这是集合视图单元格.

class BusinessCell: UICollectionViewCell {

    var imageView: UIImageView!

    var nameLabel: UILabel!

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

        imageView = UIImageView(frame: CGRect(x: 20,y: 20,width: 60,height: 60))

        imageView.contentMode = .scaleAspectFit

        nameLabel = UILabel(frame: CGRect(x: 0,y: 90,width: 100,height: 30))

        nameLabel.font = UIFont.systemFont(ofSize: 11)

        nameLabel.textAlignment = .center

        self.addSubview(imageView)

        self.addSubview(nameLabel)
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }
}

这是我制作的测试数据库的屏幕截图.