无法从其余API获取数据以加载到ViewDidLoad上

Question

我是新手，我无法解决这个问题。我可以成功地通过API进行JSON提取，但是只有在单击按钮后才能加载“表视图”上的数据。打开应用程序时，在viewDidLoad上调用相同的函数不会加载数据。我尝试了很多解决方案，但找不到错误所在这是主视图控制器代码：

import UIKit

struct ExpenseItem: Decodable {
    let name: String
    let amount: String
    let id: String
    let timestamp: String
    let description: String
}

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    @IBAction func fetchData(_ sender: Any) {
        ds()
        self.eTW.reloadData()
    }

    @IBOutlet weak var eTW: UITableView!

    var allExpenses = [ExpenseItem]()
    let expensesURL = "https://temp.cuttons.com/json/expenses.json"

    override func viewDidLoad() {
        super.viewDidLoad()
        eTW.delegate = self
        eTW.dataSource = self
        ds()
        self.eTW.reloadData()
    }

    func parseJSON(data: Data) -> [ExpenseItem] {
        var e = [ExpenseItem]()
        let decoder = JSONDecoder()
        do {
            e = try decoder.decode([ExpenseItem].self, from: data)

        } catch {
            print(error.localizedDescription)
            }
            return e
        }


    func ds()  {
        if let url = URL(string: expensesURL){
            let session = URLSession(configuration: .default)
            let task = session.dataTask(with: url) { (data, session, error) in
                if error != nil {
                    print("some error happened")
                } else {
                    if let content = data {
                        self.allExpenses = self.parseJSON(data: content)

                    }
                }
            }
            task.resume()
        }
    }

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.allExpenses.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = eTW.dequeueReusableCell(withIdentifier: "expense", for: indexPath) as! myCellTableViewCell
        cell.name.text = self.allExpenses[indexPath.row].name
        if let am = Double(self.allExpenses[indexPath.row].amount) {
            if (am > 0) {
                cell.amount.textColor = .green
            } else {
                cell.amount.textColor = .red
            }
        }
        cell.amount.text = self.allExpenses[indexPath.row].amount
        return cell
    }

谢谢L。

Answer 1