Question

是否可以从JSON获取特定元素并将其其他元素显示在collectionView上？

更广泛的问题： 这是我的JSON对象：

{
    "id": 1,
    "floor": 1,
    "full_name": "Ernst & Young Audit LLC",
    "description": "Ernst & Young («Эрнст энд Янг», в наст. время — EY) — британская аудиторско-консалтинговая компания, одна из крупнейших в мире. Основана в 1989 путём слияния американских аудиторских компаний A. C. Young, основанной Артуром Янгом в 1906 году, и Ernst & Whinney, основанной Элвином Эрнстом в 1903 году.\r\n\r\nПодробнее: http://www.ey.com/",
    "logo_url": "http://########/EY_logo13.png"
}

在这里，我想引用full_name的{{1}}，description和logo_url，这是一个整数，其值为2,3,4,5。

例如：

如果floor为1，我想从第1层获取值，如果为2，则从第二层获取值，依此类推。接下来，将其显示在我的CollectionView上。但是我的代码什么也没显示。任何帮助，将不胜感激！

这是我到目前为止所做的：

floor

CollectionView

var companies = [Employer]()
var companiesByFloor: [Int : [Employer]] = [:]

override func viewDidLoad() {
    super.viewDidLoad()
    navigationItem.title = "Карта"

    getEmployerData {
        self.employerCollectionView.reloadData()
    }
    floorCollectionView.reloadData()

    scrollView.minimumZoomScale = 1.0
    scrollView.maximumZoomScale = 5.0
}

func viewForZooming(in scrollView: UIScrollView) -> UIView? {
    return mapImage
}

func getEmployerData(completed: @escaping () -> ()) {
    let url = URL(string: "http://######/employer/")
    Alamofire.request(url!).responseJSON { response in
        let data = response.data
        do {
            self.companies = try JSONDecoder().decode([Employer].self, from: data!)

            for item in self.companies {
                let arr = Employer(floor: item.floor, full_name: item.full_name, description: item.description, logo_url: item.logo_url)
                self.companiesByFloor[item.floor] = [arr]
            }
            DispatchQueue.main.async {
                completed()
            }
        }
        catch let e{
            print(e)
        }
    }
  }
}

Screenshot of Collection View

Answer 1

您在方法do block中的getEmployerData中的代码应如下所示：

self.companies = try JSONDecoder().decode([Employer].self, from: data!)
for item in self.companies {
    if self.companiesByFloor[item.floor] == nil {
        self.companiesByFloor[item.floor] = [item]
    } else {
        self.companiesByFloor[item.floor].append(item)
    }         
}

Answer 2

要正确显示这些部分，您必须添加一个代表这些部分的数组floors：

var floors = [Int]()

将数组分组为字典非常容易

self.companies = try JSONDecoder().decode([Employer].self, from: data!)
self.companiesByFloor = Dictionary(grouping: self.companies, by: {$0.floor})
self.floors = self.companiesByFloor.keys.sorted()

DispatchQueue.main.async {
    completed()
}

然后获得numberOfItemsInSection，

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

    let floor = floors[section]
    return companiesByFloor[floor]!.count
}

您还必须实现numberOfSections

func numberOfSections(in collectionView: UICollectionView) -> Int {
    return floors.count
}

要在collectionView中显示一个值，请使用类似的

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MyCell", for: indexPath)

    let floor = floors[indexPath.section]
    let companies = companiesByFloor[floor]!
    let company = companies[indexPath.item]
    cell.someLabel.text = company.full_name
    return cell       
}

如何从JSON获取特定值并在CollectionView上显示其元素？

2 个答案: