Swift 5：从tableView numberOfRowsInSection返回数组计数时索引超出范围

Question

I'm almost done with this problem. This is the only thing left to solve.

this is what I am trying to parse: https://newsapi.org/v2/top-headlines?country=us&category=business&apiKey=API_KEY

sample[0].articles.count have an error of index out of range

I'm trying to populate the labels with the data I parsed. I tried this and it's only returning 1 cell.

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

ViewController.swift

import UIKit

struct News: Decodable {

    let articles: [Article]

    struct Article: Decodable {
        let title: String?
        let urlToImage: String?
        let description: String?
    }
}
class ViewController: UIViewController {

    @IBOutlet weak var table: UITableView!

    var sample = [News]()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        getJson()

        table.delegate = self
        table.dataSource = self

    }

    func getJson() {
        let urlString = "https://newsapi.org/v2/top-headlines?country=us&category=business&apiKey=e07d26ea273d41e2af174b026aea27b5"

        guard let url = URL(string: urlString) else { return }

        URLSession.shared.dataTask(with: url) { (data, response, error) in
            guard let data = data else { return }

            do {
                self.sample = [try JSONDecoder().decode(News.self, from: data)]
                print(self.sample[0].articles.count)
                for dict in self.sample {
                    for sam in dict.articles {
                        print(sam.title!)
                    }
                }

                DispatchQueue.main.async {
                    //reload tableView data
                    self.table.reloadData()
                }

            } catch let jsonErr {
                print("json error: ", jsonErr)
            }
        }.resume()
    }
}

extension ViewController: UITableViewDataSource, UITableViewDelegate {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return sample[0].articles.count
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
        return CGFloat(100)
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "TableViewCell") as! TableViewCell
        let json = sample[0].articles[indexPath.row]
        cell.name.text = "\(json.title!)"
        cell.link.text = "\(json.description!)"
        cell.imageUrl.text = "\(json.urlToImage!)"
        return cell
    }


}

Answer 1

You are setting sample asynchronously, tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) is called before sample contains anything. The following change will prevent the crash.

  func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return sample.first?.articles.count ?? 0
    }