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

Question

大家好，我是 swift 和编程（来自设计领域）的新手。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() {} 中）我仍然得到 false 而不是 @Publihed var doesNotificationExist:Bool = false 不更新。

请帮帮我，如果能就我做错了什么以及我需要做什么提供一些指导，我将不胜感激。

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 用于通知采用闭包的函数的调用者闭包可能已存储或以其他方式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，closure 将被调用更改您的Bool 值为 true.

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)")
    }
}

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

Trying to set @published bool to true based on results from an API call

swift

swiftui

observableobject