尝试根据 API 调用的结果将 @published bool 设置为 true

Question

首先，我对 swift 和编程非常陌生（来自设计领域）。 我正在尝试根据 posts.count 更新 doesNotificationsExist

我在Api().getPosts {} 中变得真实 我在哪里打印以下内容：

print("Api().getPosts")
print(doesNotificationExist)

但在外面（在loadData() {}）我仍然得到错误而不是@Publihed var doesNotificationExist:Bool = false 不会更新。

请帮帮我，我真的很感激一些关于我做错了什么以及我需要做什么的指导。

这是我的代码：

import SwiftUI
import Combine

public class DataStore: ObservableObject {
    @Published var posts: [Post] = []
    @Published var doesNotificationExist:Bool = false
    
    init() {
        loadData()
        startApiWatch()
    }
    
    func loadData() {
        
        Api().getPosts { [self] (posts) in
            self.posts = posts

            if posts.count >= 1 {
                doesNotificationExist = true
            }
            else {
                doesNotificationExist = false
            }
            
            print("Api().getPosts")
            print(doesNotificationExist)
        }
        print("loadData")
        print(doesNotificationExist)
    }
    
    func startApiWatch() {
        Timer.scheduledTimer(withTimeInterval: 60, repeats: true) {_ in
            self.loadData()
            
        }
    }

查看我尝试根据store.doesNotificationsExist设置图像的位置

状态栏控制器：

import AppKit
import SwiftUI

class StatusBarController {
    private var statusBar: NSStatusBar
    private var statusItem: NSStatusItem
    private var popover: NSPopover
    
    @ObservedObject var store = DataStore()
    
    init(_ popover: NSPopover)
    {
        self.popover = popover
        statusBar = NSStatusBar.init()
        statusItem = statusBar.statusItem(withLength: 28.0)
        
        statusItem.button?.action = #selector(togglePopover(sender:))
        statusItem.button?.target = self
    
        if let statusBarButton = statusItem.button {
            let itemImage = NSImage(named: store.doesNotificationExist ? "StatusItemImageNotification" : "StatusItemImage")
            statusBarButton.image = itemImage
            statusBarButton.image?.size = NSSize(width: 18.0, height: 18.0)
            statusBarButton.image?.isTemplate = true
            statusBarButton.action = #selector(togglePopover(sender:))
            statusBarButton.target = self
        }
        
    }
`Other none relevant code for the question`

 }

Answer 1

这是一个闭包，希望是@escaping。 @escaping 用于通知接受闭包的函数的调用者，闭包可能被存储或超出接收函数的范围。因此，您的外部打印语句将首先使用 bool 值 false 调用，一旦 timer 完成，将调用 closure 将您的 Bool 值更改为 是的。

检查下面的代码-：

import SwiftUI


public class Model: ObservableObject {
    //@Published var posts: [Post] = []
    @Published var doesNotificationExist:Bool = false
    
    init() {
        loadData()
       // startApiWatch()
    }
    
    func loadData() {
        
        getPost { [weak self] (posts) in
            //self.posts = posts

            if posts >= 1 {
                self?.doesNotificationExist = true
            }
            else {
                self?.doesNotificationExist = false
            }
            
            print("Api().getPosts")
            print(self?.doesNotificationExist)
        }
        print("loadData")
        print(doesNotificationExist)
    }
    
    func getPost(completion:@escaping (Int) -> ()){
        Timer.scheduledTimer(withTimeInterval: 5, repeats: true) {_ in
            completion(5)
            
        }
    }
}

struct Test1:View {
    @ObservedObject var test = Model()
    var body: some View{
        Text("\(test.doesNotificationExist.description)")
    }
}