swift - 如何使 firebase 数据库数据成为 UICollectionView 的数据源？

Question

我想将我的模型对象数据源更改为 firebase。我有一个文件用作 UICollection View 的数据源 homeViewController.swift 。 homeViewController.swift 是一个垂直排列的 collectionViewCell，每个 cell 都有自己水平排列的 collectionViewcell。

这是 models.swift 文件

import UIKit
import Firebase

class BusinessCategory: NSObject {

var name: String?
var featurebusiness: [SampleBusinesses]?
var type: String?


static func sampleBusinessCategories() -> [BusinessCategory] {
 let FastfoodCategory = BusinessCategory()
    FastfoodCategory.name = "Fast Food"
    var topFastFood = [SampleBusinesses]()

    let FastfoodApp = SampleBusinesses()
    FastfoodApp.name = "Papa Johns"
    FastfoodApp.imageName = "PJ"
    topFastFood.append(FastfoodApp)
    FastfoodCategory.featurebusiness = topFastFood


    let MobilePhoneCategory = BusinessCategory()
    MobilePhoneCategory.name = "Mobile Phones"
    var topMobilePhoneProvider = [SampleBusinesses]()
    //logic
    let MobilePhoneApp = SampleBusinesses()
    MobilePhoneApp.name = "Verizon"
    MobilePhoneApp.imageName = "verizon"
    topMobilePhoneProvider.append(MobilePhoneApp)
    MobilePhoneCategory.featurebusiness = topMobilePhoneProvider

    return [ FastfoodCategory, MobilePhoneCategory ]

我想更改目标文件，以便它由我的 firebase 数据库 (BusinessCategories) 填充。我尝试了很多选择，但一直无法弄清楚。如何将目标文件从物理输入的数据更改为 Firebase 数据？

如果有帮助，这是我的 Firebase 数据。例如，“银行”将是类别名称，单元格将由银行下的所有条目填充。

更新:我想要实现的是类似于 Appstore UI，不同类别的应用程序和每个类别是一个带有水平滚动的 Collection View 。在我的应用程序中，企业在 firebase 中列出了不同的类别，每个类别都可以水平滚动。

如何在下方更新我的 Collection View 属性？

 override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
     let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! CategoryCell

        cell.businessCategory = businessCategories?[indexPath.item]

    return cell
}

override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    if let count = businessCategories?.count{

        return count 
    }
    return 0
}

Answer 1

我希望这能让您入门。拥有数据库的整个模式会更好，但我是根据我从您的屏幕截图中看到的内容制作的。似乎也不需要单独的 BusinessCategory 树，因为您在业务树中拥有每个业务的类别类型，尽管这完全取决于您。

如果您想提供更完整的数据库屏幕截图(仅显示键和数据类型)，我很乐意修改此代码。

因为我不知道你是如何更新你的 Collection View 的，所以我做到了，所以它返回一个字典，其中键是类别，值是该类别的业务数组。如果您在 Collection View 中使用部分，这应该是一种简单的格式。

关于 typealias FirebaseRootDictionary，它可能需要修改，因为我猜测您的数据库架构是什么。

如果您对此代码有任何疑问或问题，请在下方发表评论，我会尽力解决。

所以要获取您的数据:

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

    Business.getBusinesses { (businesses) in

        print(businesses)
    }
}

然后在闭包中更新 Collection View 。

import Foundation
import Firebase

final class Business : NSObject {

    typealias FirebaseRootDictionary = Dictionary<String,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 View ，您有一个表格 View ，每个部分/类别有一个单元格。该单元格有一个 Collection View ，它有一个带有 ImageView 和标签的 Collection View 单元格。所以这里我有一个 TableView Controller 可以处理所有这些。

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
    }
}

表格 View 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 Collection View 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)
    }
}

这里是我做的测试数据库的截图。