Ios 表上的刷新程序-索引超出范围错误

我已经实现了下面的代码，运行良好，它显示正确的数据，在拉入时刷新。但是，当多次快速发送刷新器时，最终会导致致命错误-索引超出范围

这让我抓狂，有人能看到我的代码有什么问题吗

    override func viewDidLoad()
{
    super.viewDidLoad()

    nameArray.removeAll(keepingCapacity: false)
    addressArray.removeAll(keepingCapacity: false)


    refresher = UIRefreshControl()
    refresher.attributedTitle = NSAttributedString(string: "Reloading")
    refresher.addTarget(self, action: #selector(downloadJsonWithURL), for: UIControlEvents.valueChanged)
    tableView.addSubview(refresher)
    self.downloadJsonWithURL()

}


func downloadJsonWithURL()
{
    // Emtpy arrays to avoid index out of range crash
    nameArray.removeAll(keepingCapacity: false)
    addressArray.removeAll(keepingCapacity: false)

    let url = NSURL(string: urlString)

    URLSession.shared.dataTask(with: (url as URL?)!, completionHandler: {(data, response, error) -> Void in


        if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary {

            if let projectArray = jsonObj!.value(forKey: "project") as? NSArray {
                for project in projectArray{
                    if let projectDict = project as? NSDictionary {
                        if let name = projectDict.value(forKey: "societe") {
                            self.nameArray.append(name as! String)
                        }
                    }
                    if let projectDict = project as? NSDictionary {
                        if let name = projectDict.value(forKey: "address") {
                            self.addressArray.append(name as! String)
                        }
                    }
                }
            }

            OperationQueue.main.addOperation(
                {
                    self.tableView.reloadData()
                    self.refresher.endRefreshing()
            })
        }
    }).resume()

}

// Count length of array and create number of cells accordingly
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
    return nameArray.count
}

// Create cell data from arrays
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! TableViewCell
    cell.projectDesc.text = nameArray[indexPath.row].uppercased()
    cell.projectAddress.text = addressArray[indexPath.row]
    return cell
}

---

你能试试看这是否能解决它吗？因为这似乎是它崩溃的地方

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
    let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! TableViewCell

    if nameArray.count > indexPath.row && addressArray.count > indexPath.row {
        cell.projectDesc.text = nameArray[indexPath.row].uppercased()
        cell.projectAddress.text = addressArray[indexPath.row]
    }
    return cell
}

添加

if refresher.isRefreshing

将防止多次调用此数据请求

func downloadJsonWithURL() {

    // If already refreshing don't run the code below
    if refresher.isRefreshing {

        // Emtpy arrays to avoid index out of range crash
        nameArray.removeAll(keepingCapacity: false)
        addressArray.removeAll(keepingCapacity: false)

        let url = NSURL(string: urlString)

        URLSession.shared.dataTask(with: (url as URL?)!, completionHandler: {(data, response, error) -> Void in


            if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary {

                if let projectArray = jsonObj!.value(forKey: "project") as? NSArray {
                    for project in projectArray{
                        if let projectDict = project as? NSDictionary {
                            if let name = projectDict.value(forKey: "societe") {
                                self.nameArray.append(name as! String)
                            }
                        }
                        if let projectDict = project as? NSDictionary {
                            if let name = projectDict.value(forKey: "address") {
                                self.addressArray.append(name as! String)
                            }
                        }
                    }
                }

                OperationQueue.main.addOperation(
                    {
                        self.tableView.reloadData()
                        self.refresher.endRefreshing()
                })
            }
        }).resume()
    }
}

---

问题是您在接收响应之前正在从数组中删除对象。它创建了一个场景，其中您的

numberOfRowsInSection

返回一个不同的值，当调用

cellForRowAtIndexPath

时，它在数组中有一个不同的（零）项，这会由于索引超出范围问题而导致应用程序崩溃。这通常是多线程的问题

要解决此问题，请仅在成功从API调用接收数据时清空阵列。为此，您需要将removeAll元素的代码添加到projectArray{中项目的

上方

这使您的代码类似于：

override func viewDidLoad()
{
    super.viewDidLoad()

    nameArray.removeAll(keepingCapacity: false)
    addressArray.removeAll(keepingCapacity: false)

    refresher = UIRefreshControl()
    refresher.attributedTitle = NSAttributedString(string: "Reloading")
    refresher.addTarget(self, action: #selector(downloadJsonWithURL), for: UIControlEvents.valueChanged)
    tableView.addSubview(refresher)
    self.downloadJsonWithURL()
}

func downloadJsonWithURL()
{
    let url = NSURL(string: urlString)

    URLSession.shared.dataTask(with: (url as URL?)!, completionHandler: {(data, response, error) -> Void in


        if let jsonObj = try? JSONSerialization.jsonObject(with: data!, options: .allowFragments) as? NSDictionary {

            if let projectArray = jsonObj!.value(forKey: "project") as? NSArray {
                nameArray.removeAll(keepingCapacity: false)
                addressArray.removeAll(keepingCapacity: false)

                for project in projectArray{
                    if let projectDict = project as? NSDictionary {
                        if let name = projectDict.value(forKey: "societe") {
                            self.nameArray.append(name as! String)
                        }
                    }
                    if let projectDict = project as? NSDictionary {
                        if let name = projectDict.value(forKey: "address") {
                            self.addressArray.append(name as! String)
                        }
                    }
                }
            }

            OperationQueue.main.addOperation(
                {
                    self.tableView.reloadData()
                    self.refresher.endRefreshing()
            })
        }
    }).resume()
}

由于nameArray.removeAll（保留容量：false）addressArray.removeAll（保留容量：false）导致崩溃.end refresh的作用是什么？当您从服务器获得成功响应时，您需要删除对象。KKRocks，你好，伙计。刷新工作…只有在垃圾邮件刷新时才会发生崩溃。我应该将removeAll方法移动到哪里？@Priyal它停止刷新方法。这并没有起作用，仍然会崩溃…而且它在第一个v上显示空表在触发刷新之前卸载。很高兴！它有帮助。