ios - 在 iOS Swift 2.1 中完成 json 请求后重新加载 View /数据

Question

我有一个 SectionsData.swift 文件，我从 get http 请求中获取一些数据:

import Foundation
import Alamofire

class SectionsData {
    func getSectionsFromData() -> [Section] {
        var sectionsArray = [Section]()

        let animals = Section(title: "Animals", objects:  ["Cats", "Dogs", "Lions", "Birds"], place: "Jungle")
        let vehicles = Section(title: "Vehicles", objects: ["Cars", "Bicycle"], place: "Road")
        let movies = Section(title: "Movies", objects: ["Sound", "Music"], place: "Cinema")

        sectionsArray.append(animals)
        sectionsArray.append(vehicles)
        sectionsArray.append(movies)

        Alamofire.request(.GET, "https://example.com")
            .responseJSON { response in
                if let JSON = response.result.value {
                    var openEvents = Section(title: "Events", objects: [], place: "Rooms")
                    for index in 0...9 {
                        let eventName = JSON["events"]!![index]["name"]! as! String
                        openEvents.items.append(eventName)
                    }

                    sectionsArray.append(openEvents)

                }
        }

        return sectionsArray
    }
}

在 ViewController.swift 文件中，我尝试在 JSON 请求完成后重新加载 View :

import UIKit

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

    @IBOutlet weak var tableView: UITableView!

    var sections: [Section] = SectionsData().getSectionsFromData()

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return sections.count
    }

    func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return sections[section].heading
    }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return sections[section].items.count 
    }
    ...

目前，我只能看到带有“动物”、“车辆”和“电影” TableView 部分的静态数据，没有“事件”部分。

我相信我需要在某处重新加载 View 。我该怎么做？

Answer 1

首先，在您的 getSectionsFromData() 中，您正在调用对 Alamofire.request() 的异步调用，它不会在 的适当时间执行code>sectionsArray 以获取返回的数据。您实际上是从 getSectionsFromData 返回静态数组。

要解决此问题，您可以在 getSectionsFromData()

中使用回调

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate     {    

    var sections: [Section] = []

    override func viewDidLoad() {
        super.viewDidLoad()

        SecionsData().getSectionsFromData({
            sections in

            self.sections = sections

            self.tableView.reloadData()
        })
    }
}

class SectionsData {

    func getSectionsFromData(callback: (sections: [Section]) -> ()) {

        var sectionsArray = [Section]()

        let animals = Section(title: "Animals", objects:  ["Cats", "Dogs", "Lions", "Birds"], place: "Jungle")
        let vehicles = Section(title: "Vehicles", objects: ["Cars", "Bicycle"], place: "Road")
        let movies = Section(title: "Movies", objects: ["Sound", "Music"], place: "Cinema")

        sectionsArray.append(animals)
        sectionsArray.append(vehicles)
        sectionsArray.append(movies)


        Alamofire.request(.Get, "https://example.com")
            .responseJSON { response in

            if let JSON = response.result.value {
                var openEvents = Section(title: "Events", objects: [], place: "Rooms")
                for index in 0...9 {
                    let eventName = JSON["events"]!![index]["name"]! as! String
                    openEvents.items.append(eventName)
                }

                sectionsArray.append(openEvents)
            }

            // This will pass the sections with or without any fetched data into the callback
            callback(sections: sectionsArray)
        }
    }
}

Swift Closures