Swift3中如何排序JSON数据并加载至UITableView？加载失败求助

Hey there! Let's work through your problem step by step—loading JSON into a UITableView and sorting that data in Swift 3 can trip you up if you're missing a few key pieces, so let's break it down clearly.

Step 1: Create Data Models for Your JSON Structure #

Your JSON has nested objects (like address and company), so we'll make model classes to store this parsed data properly. Swift 3 doesn't have Codable (that came in Swift 4+), so we'll use dictionary-to-model initialization:

// Nested Address model
class Address: NSObject {
    var street: String?
    var suite: String?
    var city: String?
    var zipcode: String?
    
    init(dictionary: [String: Any]) {
        self.street = dictionary["street"] as? String
        self.suite = dictionary["suite"] as? String
        self.city = dictionary["city"] as? String
        self.zipcode = dictionary["zipcode"] as? String
        // Add lat/lng properties here if you need the geo data
    }
}

// Nested Company model
class Company: NSObject {
    var name: String?
    var catchPhrase: String?
    
    init(dictionary: [String: Any]) {
        self.name = dictionary["name"] as? String
        self.catchPhrase = dictionary["catchPhrase"] as? String
    }
}

// Main User model
class User: NSObject {
    var id: Int?
    var name: String?
    var username: String?
    var email: String?
    var address: Address?
    var phone: String?
    var website: String?
    var company: Company?
    
    init(dictionary: [String: Any]) {
        self.id = dictionary["id"] as? Int
        self.name = dictionary["name"] as? String
        self.username = dictionary["username"] as? String
        self.email = dictionary["email"] as? String
        
        // Parse nested address object
        if let addressDict = dictionary["address"] as? [String: Any] {
            self.address = Address(dictionary: addressDict)
        }
        
        // Parse nested company object
        if let companyDict = dictionary["company"] as? [String: Any] {
            self.company = Company(dictionary: companyDict)
        }
        
        self.phone = dictionary["phone"] as? String
        self.website = dictionary["website"] as? String
    }
}

Step 2: Parse JSON into a User Array #

Next, we'll take your JSON data (whether from a local file or API) and convert it into an array of User objects.

For Local JSON Files:

var usersArray: [User] = []
@IBOutlet weak var tableView: UITableView!

func loadLocalJSON() {
    // Locate the JSON file in your app bundle
    guard let jsonPath = Bundle.main.path(forResource: "users", ofType: "json") else {
        print("Error: JSON file not found in bundle")
        return
    }
    
    do {
        let jsonData = try Data(contentsOf: URL(fileURLWithPath: jsonPath))
        // Convert data to JSON array
        guard let jsonArray = try JSONSerialization.jsonObject(with: jsonData, options: .allowFragments) as? [[String: Any]] else {
            print("Error: JSON is not a valid array")
            return
        }
        
        // Map JSON array to User objects
        usersArray = jsonArray.map { User(dictionary: $0) }
        // Refresh the table view
        tableView.reloadData()
    } catch let error {
        print("Parsing error: \(error.localizedDescription)")
    }
}

For API-Fetched JSON:

func fetchUsersFromAPI() {
    guard let apiURL = URL(string: "https://your-api-endpoint-here.com/users") else {
        print("Error: Invalid API URL")
        return
    }
    
    URLSession.shared.dataTask(with: apiURL) { [weak self] data, response, error in
        guard let data = data, error == nil else {
            print("Fetch error: \(error?.localizedDescription ?? "Unknown error")")
            return
        }
        
        do {
            guard let jsonArray = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as? [[String: Any]] else {
                print("Error: API response is not a valid array")
                return
            }
            
            // Map to User array and refresh table on main thread
            self?.usersArray = jsonArray.map { User(dictionary: $0) }
            DispatchQueue.main.async {
                self?.tableView.reloadData()
            }
        } catch let error {
            print("Parsing error: \(error.localizedDescription)")
        }
    }.resume()
}

Step 3: Connect to UITableView Data Source #

Make sure your view controller conforms to UITableViewDataSource and implement the required methods. Don't forget to set the table view's data source (via Storyboard outlets or code):

override func viewDidLoad() {
    super.viewDidLoad()
    tableView.dataSource = self
    // Call your JSON loading function here
    loadLocalJSON()
    // OR fetchUsersFromAPI()
}

// MARK: - UITableView Data Source
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return usersArray.count
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    // Use your cell reuse identifier (set this in Storyboard first!)
    let cell = tableView.dequeueReusableCell(withIdentifier: "UserCell", for: indexPath)
    let currentUser = usersArray[indexPath.row]
    
    // Populate cell with user data
    cell.textLabel?.text = currentUser.name
    cell.detailTextLabel?.text = currentUser.email
    
    // Example: Show nested address data (city)
    if let userCity = currentUser.address?.city {
        cell.detailTextLabel?.text = "\(currentUser.email ?? "") | \(userCity)"
    }
    
    return cell
}

Step 4: Sort the User Array #

To sort your data, add a sort call right after parsing the JSON. Here are common sorting options:

Sort by Name (Ascending):

usersArray.sort {
    guard let name1 = $0.name, let name2 = $1.name else { return false }
    return name1 < name2
}

Sort by ID (Descending):

usersArray.sort {
    guard let id1 = $0.id, let id2 = $1.id else { return false }
    return id1 > id2
}

Add this sort code right before reloading the table view. For example, in loadLocalJSON():

// After mapping to User array
usersArray = jsonArray.map { User(dictionary: $0) }
// Sort here
usersArray.sort {
    guard let name1 = $0.name, let name2 = $1.name else { return false }
    return name1 < name2
}
tableView.reloadData()

Quick Troubleshooting Tips #

• Double-check your JSON format: The sample JSON you provided is missing a closing } at the end—make sure your actual JSON is valid.
• Ensure your table view's data source is connected (either via Storyboard or tableView.dataSource = self).
• Always refresh the table view on the main thread (critical for API-fetched data).
• Verify your cell reuse identifier matches what's in your code and Storyboard.

内容的提问来源于stack exchange，提问作者Ankit Kumawat