在 SWIFT 中使用 NSDictionary 填充 UITable [英] Populating a UITable with NSDictionary in SWIFT

问题描述

我有一个从 JSON 请求中检索的字典，我想用这些值填充一个表.我认为一切都很好，但是我在类声明中收到一个错误 Type SubjectsViewController 不符合协议 'UITableViewDataSource' 我正在使用故事板，并且我在 UI 上添加了表格视图datasource 和 delegate 据我所知，我正在正确地实现这些功能.我在下面添加了代码的相关部分.

I have a dictionary that I retrieve from a JSON request and I would like to populate a table with those values. I think everything is okay, however I am getting an error in the class declaration that Type SubjectsViewController does not conform to protocol 'UITableViewDataSource' I am using a storyboard, and I added the table view on the UI to datasource and delegate and as far as I know, I am implementing the functions correctly. I have added the relevant parts of my code below.

查看 this 可能有用，这是我发布的问题了解我为什么使用回调.提前致谢！

It may be useful to see this which is a question I posted to understand why I am using the callback. Thanks in advance!

class SubjectsViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

  override func viewDidLoad() {
        super.viewDidLoad()

        getSubjects(callback: {(resultValue)-> Void in

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

            func tableView(_ tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
                let cell = UITableViewCell(style: UITableViewCellStyle.default, reuseIdentifier: "cell")
                cell.textLabel?.text = resultValue[indexPath.row] as! String?
                return cell
            }

        })
    }

    // Initialise components of the view
    let UserDetails = UserDefaults.standard.stringArray(forKey: "UserDetailsArray") ?? [String]()
    @IBOutlet weak var tableView: UITableView!

    // Function to retrieve the subjects for the user
    func getSubjects(callback: @escaping (NSDictionary)-> Void){

        let myUrl = NSURL(string: "www.mydomain.com/retrieveSubjects.php");
        let request = NSMutableURLRequest(url:myUrl as! URL)
        let user_id = UserDetails[0]
        request.httpMethod = "POST";
        let postString = "user_id=\(user_id)";
        request.httpBody = postString.data(using: String.Encoding.utf8);

        let task = URLSession.shared.dataTask(with: request as URLRequest){
            data, response, error in

            if error != nil {
                print("error=\(error)")
                return
            }

            var err: NSError?
            do {
                let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
                if let parseJSON = json {
                    let resultValue: NSDictionary = parseJSON["subjects"] as! NSDictionary
                    callback(resultValue)
                }
            } catch let error as NSError {
                err = error
                print(err!);
            }
        }
        task.resume();
    }
}

编辑:在解开一个可选值时，CLASS 抛出意外发现 nil

EDIT: CLASS throwing unexpectedly found nil while unwrapping an optional value

class SubjectsViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

var dataDict: [String:AnyObject]?
@IBOutlet var tableView: UITableView!
let userDetails: [String] = UserDefaults.standard.stringArray(forKey:"UserDetailsArray")!

override func viewDidLoad() {
    super.viewDidLoad()
    self.dataDict = [String:AnyObject]()
    self.tableView.delegate = self
    self.tableView.dataSource = self
    self.getSubjects()
}

func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

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

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell(style: UITableViewCellStyle.value1, reuseIdentifier: "cell")
    let array = self.dataDict?[String(indexPath.row)] as! [String]

    print(array)

    cell.textLabel?.text = array[0]
    cell.detailTextLabel?.text = array[1]
    return cell
}

func getSubjects() {

    let myUrl = NSURL(string: "www.mydomain/retrieveSubjects.php");
    let request = NSMutableURLRequest(url:myUrl as! URL)
    let user_id = userDetails[0]
    request.httpMethod = "POST";
    let postString = "user_id=\(user_id)";
    request.httpBody = postString.data(using: String.Encoding.utf8);

    let task = URLSession.shared.dataTask(with: request as URLRequest) {
        data, response, error in

        if error != nil {
            print("error=\(error)")
            return
        }

        var err: NSError?
        do {
            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
            if let parseJSON = json {
                let resultValue = parseJSON["subjects"] as! [String:AnyObject]
                self.dataDict = resultValue
                self.tableView.reloadData()
            }
        } catch let error as NSError {
            err = error
            print(err!);
        }
    }
    task.resume();
}
}

推荐答案

以下是您需要做的:

首先，为您的数据创建一个类变量.把它放在你的类声明下:

First, create a class variable for your data. Put this under your class declaration:

var dataDict: [String:AnyObject]?

然后，为了使事情井井有条，请将您的 tableView 属性和您的 userDetails 属性直接放在 dataDict 下.

Then, to keep things organized, put your tableView property and your userDetails property directly under the dataDict.

@IBOutlet var tableView: UITableView!
let userDetails: [String] = UserDefaults.standard.stringArray(forKey:"UserDetailsArray")

现在，您的 viewDidLoad 方法应如下所示:

Now, your viewDidLoad method should look like this:

override func viewDidLoad() {
    super.viewDidLoad()
    self.dataDict = [String:AnyObject]()
    self.tableView.delegate = self
    self.tableView.dataSource = self
    self.getSubjects()
}

在此之下，您需要处理 UITableViewDataSource 方法:

Below that, you'll want to take care of the UITableViewDataSource methods:

func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

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

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell(style: UITableViewCellStyle.value1, reuseIdentifier: "cell")
    if let array = self.dataDict[String(indexPath.row)] as? [String] {
        cell.textLabel?.text = array[0]
        cell.detailTextLabel?.text = array[1]
    }
    return cell
}

最后，您需要实现 getSubjects() 方法:

Lastly, you need to implement the getSubjects() method:

func getSubjects() {

    let myUrl = NSURL(string: "www.mydomain.com/retrieveSubjects.php");
    let request = NSMutableURLRequest(url:myUrl as! URL)
    let user_id = UserDetails[0]
    request.httpMethod = "POST";
    let postString = "user_id=\(user_id)";
    request.httpBody = postString.data(using: String.Encoding.utf8);

    let task = URLSession.shared.dataTask(with: request as URLRequest) {
        data, response, error in

        if error != nil {
            print("error=\(error)")
            return
        }

        var err: NSError?
        do {
            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
            if let parseJSON = json {
                let resultValue = parseJSON["subjects"] as! [String:AnyObject]
                self.dataDict = resultValue
                self.tableView.reloadData()
            }
        } catch let error as NSError {
            err = error
            print(err!);
        }
    }
    task.resume();
}

总而言之，您的代码应如下所示:

Altogether, your code should look like this:

class SubjectsViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

    var dataDict: [String:AnyObject]?
    @IBOutlet var tableView: UITableView!
    let userDetails: [String] = UserDefaults.standard.stringArray(forKey:"UserDetailsArray")

    override func viewDidLoad() {
        super.viewDidLoad()
        self.dataDict = [String:AnyObject]()
        self.tableView.delegate = self
        self.tableView.dataSource = self
        self.getSubjects()
    }

    func numberOfSections(in tableView: UITableView) -> Int {
        return 1
    }

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

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = UITableViewCell(style: UITableViewCellStyle.value1, reuseIdentifier: "cell")
        if let array = self.dataDict[String(indexPath.row)] as? [String] {
            cell.textLabel?.text = array[0]
            cell.detailTextLabel?.text = array[1]
        }
        return cell
    }

    func getSubjects() {

        let myUrl = NSURL(string: "www.mydomain.com/retrieveSubjects.php");
        let request = NSMutableURLRequest(url:myUrl as! URL)
        let user_id = UserDetails[0]
        request.httpMethod = "POST";
        let postString = "user_id=\(user_id)";
        request.httpBody = postString.data(using: String.Encoding.utf8);

        let task = URLSession.shared.dataTask(with: request as URLRequest) {
            data, response, error in

            if error != nil {
                print("error=\(error)")
                return
            }

            var err: NSError?
            do {
                let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
                if let parseJSON = json {
                    let resultValue = parseJSON["subjects"] as! [String:AnyObject]
                    self.dataDict = resultValue
                    self.tableView.reloadData()
                }
            } catch let error as NSError {
                err = error
                print(err!);
            }
        }
        task.resume();
    }
}

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