在视图和类SwiftUI之间传递文本

Question

当用户将一个十六进制代码粘贴到我的textfield中时，我希望我的API函数接受这个十六进制代码，并在API调用中使用它作为参数。这意味着我必须从我的视图(包含textfield)到我的类(包含API调用)共享数据。做这件事最好的方法是什么？感谢你的时间和建议

视图：

import SwiftUI

struct TestingText: View {
    
    @StateObject var fetch = fetchResults()
    @Binding var text: String
    
    var body: some View {
        
        VStack {
            
            TextField("Paste Clout Hexcode Here", text: $text)
                .font(.title2)
                .padding()
            
            Text(fetch.clout.postFound?.body ?? "n/a")
            
        }
    }
}

struct TestingText_Previews: PreviewProvider {
    static var previews: some View {
        TestingText(text: .constant("8004bb672ad3f46118775cd4b2cb5306c63f6d68787457990bf0d2fda3f7993a"))
    }
}

具有API调用的类：

class fetchResults: ObservableObject {
    
    @Published var clout = Cloutington()
    @Published var dataHasLoaded = false
    @State var postHashHex: String = "8004bb672ad3f46118775cd4b2cb5306c63f6d68787457990bf0d2fda3f7993a"
    
    
    init() {
        
        getData { clout in
            self.clout = clout
        }
        
    }
    
    private func getData(completion: @escaping (Cloutington) -> ()) {
        
        let parameters =  "{\r\n \"PostHashHex\": \"\(postHashHex)\"\r\n}"
        let postData = parameters.data(using: .utf8)
        var request =  URLRequest(url: URL(string: "https://bitclout.com/api/v0/get-single-post")!,timeoutInterval: Double.infinity)
        request.addValue("application/json", forHTTPHeaderField: "Content-Type")
        request.httpBody = postData
        request.httpMethod = "POST"
        
        let task =  URLSession.shared.dataTask(with: request) { (responseData, response, error) in

            print(error)
            print(response)
            print(responseData)
            
            if let resData = responseData {
                let decoder = JSONDecoder()
                
                do
                {
                    let finalData = try decoder.decode(Cloutington.self, from: resData)
                    DispatchQueue.main.async {

                        completion(finalData)
                        self.dataHasLoaded = true

                    }
                    
                }
                catch (let error)
                {
                    print(error)
                }

            }
            
        }
        task.resume()
        
    }
    
}

带有JSON数据的模型：

import Foundation

struct Cloutington: Decodable {
    
    var postFound: PostFound?
    
    enum CodingKeys: String, CodingKey {
        case postFound = "PostFound"
        
    }
    
}

struct PostFound: Decodable {
    
    var id: String?
    var postHashHex, posterPublicKeyBase58Check, parentStakeID, body: String?
    var imageURLs: [String]?
    //    var recloutedPostEntryResponse: JSONNull?
    var creatorBasisPoints, stakeMultipleBasisPoints: Int?
    var timestampNanos: Double?
    var isHidden: Bool?
    var confirmationBlockHeight: Int?
    var inMempool: Bool?
    var profileEntryResponse: ProfileEntryResponse?
    var likeCount, diamondCount: Int?
    var isPinned: Bool?
    var commentCount, recloutCount: Int?
    var diamondsFromSender: Int?
    
    enum CodingKeys: String, CodingKey {
        case postHashHex = "PostHashHex"
        case posterPublicKeyBase58Check = "PosterPublicKeyBase58Check"
        case parentStakeID = "ParentStakeID"
        case body = "Body"
        case imageURLs = "ImageURLs"
        case creatorBasisPoints = "CreatorBasisPoints"
        case stakeMultipleBasisPoints = "StakeMultipleBasisPoints"
        case timestampNanos = "TimestampNanos"
        case isHidden = "IsHidden"
        case confirmationBlockHeight = "ConfirmationBlockHeight"
        case inMempool = "InMempool"
        case profileEntryResponse = "ProfileEntryResponse"
        case likeCount = "LikeCount"
        case diamondCount = "DiamondCount"
        case isPinned = "IsPinned"
        case commentCount = "CommentCount"
        case recloutCount = "RecloutCount"
        case diamondsFromSender = "DiamondsFromSender"
    }
}

// MARK: - ProfileEntryResponse
struct ProfileEntryResponse: Decodable {
    var publicKeyBase58Check, username, profileEntryResponseDescription, profilePic: String?
    var isHidden, isReserved, isVerified: Bool?
    var coinPriceBitCloutNanos, stakeMultipleBasisPoints: Int?
    
    enum CodingKeys: String, CodingKey {
        case publicKeyBase58Check = "PublicKeyBase58Check"
        case username = "Username"
        case profileEntryResponseDescription = "Description"
        case profilePic = "ProfilePic"
        case isHidden = "IsHidden"
        case isReserved = "IsReserved"
        case isVerified = "IsVerified"
        case coinPriceBitCloutNanos = "CoinPriceBitCloutNanos"
        case stakeMultipleBasisPoints = "StakeMultipleBasisPoints"
    }
}

Answer 1

首先，不要像fetchResults那样用小写命名类，也不要像调用动作那样调用类:每个程序员都希望fetchResults()是一个函数调用。使用类似于ResultFetcher的东西来命名这个类。类实例通常是小写的类名，或者它的一部分：

@StateObject var resultFetcher = ResultFetcher()
// or
@StateObject var fetcher = ResultFetcher()

您只能在@State视图中使用SwiftUI，不能在ObservableObject中使用它。如果您需要在更新该变量后更新视图，或者使用未注释的变量，请使用@Published。

在您的示例中，它看起来不需要存储这个哈希字符串；您可以直接从视图中传递它。

可以使用.onChange(of: text)跟踪对@State或@Binding变量的更改：

TextField("Paste Clout Hexcode Here", text: $text)
    .font(.title2)
    .padding()
    .onChange(of: text) { text in
        resultFetcher.updateData(postHashHex: text)
    }

不确定是否需要使用硬编码十六进制代码对updateData的初始调用，无论如何，您的视图模型可以更新为：

class ResultFetcher: ObservableObject {

    @Published var clout = Cloutington()
    @Published var dataHasLoaded = false
    private let initialPostHashHex: String = "8004bb672ad3f46118775cd4b2cb5306c63f6d68787457990bf0d2fda3f7993a"

    init() {
        updateData(postHashHex: initialPostHashHex)
    }
    
    func updateData(postHashHex: String) {
        getData(postHashHex: postHashHex) { clout in
            self.clout = clout
        }
    }

    private func getData(postHashHex: String, completion: @escaping (Cloutington) -> ()) {
        // your code
    }
}