Question

这里我在xml中获取数据，并且已经检索到Dictionary以加载tableView。工作流程 - 当用户在主屏幕上并点击创建按钮并进入下一个搜索产品屏幕时，用户可以使用他们的亚马逊产品。搜索到的产品被加载到表格视图单元格中。

我的问题是当点击创建按钮tableView尝试加载数据及其崩溃时

崩溃线是结果！.count。

这是我试过的代码：

 var results: [[String: String]]?
 var currentDictionary: [String: String]? // the current dictionary
 var currentValue: String?                // the current value for one of the 
 keys in the dictionary
 let recordKey = "ItemAttributes"
 let dictionaryKeys = Set<String>(["Title"])

  func parserDidStartDocument(_ parser: XMLParser) {
    results = []
  }

// start element
//
// - If we're starting a "record" create the dictionary that will hold the results
// - If we're starting one of our dictionary keys, initialize `currentValue` (otherwise leave `nil`)

func parser(_ parser: XMLParser, didStartElement elementName: String, namespaceURI: String?, qualifiedName qName: String?, attributes attributeDict: [String : String]) {
    if elementName == recordKey {
        currentDictionary = [:]
    } else if dictionaryKeys.contains(elementName) {
        currentValue = ""
    }
  }

// found characters
//
// - If this is an element we care about, append those characters.
// - If `currentValue` still `nil`, then do nothing.

func parser(_ parser: XMLParser, foundCharacters string: String) {
    currentValue? += string
}

// end element
//
// - If we're at the end of the whole dictionary, then save that dictionary in our array
// - If we're at the end of an element that belongs in the dictionary, then save that value in the dictionary

func parser(_ parser: XMLParser, didEndElement elementName: String, namespaceURI: String?, qualifiedName qName: String?) {
    if elementName == recordKey {
        results!.append(currentDictionary!)
        currentDictionary = nil
    } else if dictionaryKeys.contains(elementName) {
        currentDictionary![elementName] = currentValue
        currentValue = nil
    }
 }

// Just in case, if there's an error, report it. (We don't want to fly blind here.)

func parser(_ parser: XMLParser, parseErrorOccurred parseError: Error) {
    print(parseError)

    currentValue = nil
    currentDictionary = nil
    results = nil
 }

//         func numberOfSectionsInTableView(tableView: UITableView) -> Int {
//            return 1
//        }

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

    return results!.count
   }

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

    let productlist = ProductName[indexPath.row]
    print("prodic:::\(productlist)")

    //        cell.amazonProductTitle?.text = productlist[indexPath.row]

    //        cell.detailTextLabel?.text = book.bookAuthor

    return cell
 }

Answer 1

永远不要将表视图数据源数组声明为可选。

如果在初始化数组之前调用numberOfRows，则应用程序崩溃。

声明results

var results = [[String: String]]()

在parserDidStartDocument以及parseErrorOccurred中清除数组

results.removeAll()

请注意，每个展开的部队都会导致崩溃并且您使用了很多惊叹号！

如何在Swift中的UITableViewCell中加载字典数据？

1 个答案: