SwiftUI crypto app — Combine yordamida tangalar rasmlarini yuklash

import Foundation
import SwiftUI
import Combine

class CoinImageService {

    // Yuklangan rasmni saqlovchi publisher
    @Published var image: UIImage? = nil

    private var imageSubscription: AnyCancellable?
    private let coin: CoinModel

    init(coin: CoinModel) {
        self.coin = coin
        getCoinImage()
    }

    private func getCoinImage() {
        // Tanganing rasm URL manzilini tekshiramiz
        guard let url = URL(string: coin.image) else { return }

        // NetworkingManager-ning download funksiyasini chaqiramiz
        imageSubscription = NetworkingManager.download(url: url)
            // Yuklangan Data-ni UIImage formatiga o'tkazamiz
            .tryMap({ (data) -> UIImage? in
                return UIImage(data: data)
            })
            // Natijani asosiy oqimda qabul qilamiz
            .sink(receiveCompletion: NetworkingManager.handleCompletion, receiveValue: { [weak self] (returnedImage) in
                // Rasmni o'zgaruvchiga saqlaymiz va obunani yopamiz
                self?.image = returnedImage
                self?.imageSubscription?.cancel()
            })
    }
}

import Foundation
import SwiftUI
import Combine

class CoinImageViewModel: ObservableObject {

    @Published var image: UIImage? = nil
    @Published var isLoading: Bool = false

    private let coin: CoinModel
    private let dataService: CoinImageService
    private var cancelables = Set<AnyCancellable>()

    init(coin: CoinModel) {
        self.coin = coin
        // Har bir tanga uchun alohida rasm xizmatini ishga tushiramiz
        self.dataService = CoinImageService(coin: coin)
        self.isLoading = true
        addSubscribers()
    }

    private func addSubscribers() {
        // Servisdagi image publisher-ga obuna bo'lamiz
        dataService.$image
            .sink { [weak self] (_) in
                // Rasm yuklanib bo'lingach, yuklanish holatini yakunlaymiz
                self?.isLoading = false
            } receiveValue: { [weak self] (returnedImage) in
                // Qabul qilingan rasmni ViewModel-dagi nashr etiluvchi image-ga bog'laymiz
                self?.image = returnedImage
            }
            .store(in: &cancelables)
    }
}

import SwiftUI

struct CoinImageView: View {

    // ViewModel-ni StateObject sifatida init ichida bog'laymiz
    @StateObject var vm: CoinImageViewModel

    init(coin: CoinModel) {
        // _vm orqali StateObject-ni o'rab turgan o'zgaruvchini (wrapper) o'zimiz yaratamiz
        _vm = StateObject(wrappedValue: CoinImageViewModel(coin: coin))
    }

    var body: some View {
        ZStack {
            if let image = vm.image {
                // Rasm muvaffaqiyatli yuklansa ko'rsatamiz
                Image(uiImage: image)
                    .resizable()
                    .scaledToFit()
            } else if vm.isLoading {
                // Rasm hali yuklanayotgan bo'lsa
                ProgressView()
            } else {
                // Rasm yuklashda xatolik bo'lsa, savol belgisi chiqadi
                Image(systemName: "questionmark")
                    .foregroundColor(Color.theme.secondaryText)
            }
        }
    }
}

struct CoinImageView_Previews: PreviewProvider {
    static var previews: some View {
        CoinImageView(coin: dev.coin)
            .padding()
            .previewLayout(.sizeThatFits)
    }
}

// CoinRowView.swift kengaytmasi (Extension) ichida:
private var leftColumn: some View {
    HStack(spacing: 0) {
        Text("\(coin.rank)")
            .font(.caption)
            .foregroundColor(Color.theme.secondaryText)
            .frame(width: 30)

        // Vaqtinchalik Circle o'rniga CoinImageView qo'yamiz
        CoinImageView(coin: coin)
            .frame(width: 30, height: 30)

        Text(coin.symbol.uppercased())
            .font(.headline)
            .padding(.leading, 6)
            .foregroundColor(Color.theme.accent)
    }
}