Question

我正在研究我在教程中看到的表视图项目，然后我遇到了这段代码，它给了我**error: Definition conflicts with previous value.**

这段代码是：

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int, titleForHeaderInSection section:Int)  -> String? {
    // Return the number of rows in the section.
    return animalSelectionTitles[section]

}

我试过改变字符串？到String或Int，但是String给了我相同的错误，Int在返回行上给了我一个错误。

这是我的完整代码：

import UIKit


class AnimalTableViewController: UITableViewController {

var animalsDict = [String: [String]] ()
var animalSelectionTitles = [String] ()

let animals = ["Bear", "Black Swan", "Buffalo", "Camel", "Cockatoo", "Dog", "Donkey", "Emu", "Giraffe", "Greater Rhea", "Hippopotamus", "Horse", "Koala", "Lion", "Llama", "Manatus", "Meerkat", "Panda", "Peacock", "Pig", "Platypus", "Polar Bear", "Rhinoceros", "Seagull", "Tasmania Devil", "Whale", "Whale Shark", "Wombat"]

func createAnimalDict() {
    for animal in animals {
        let animalKey = animal.substringFromIndex(advance(animal.startIndex, 1))
        if var animalValues = animalsDict[animalKey] {
            animalValues.append(animal)
            animalsDict[animalKey] = animalValues
        } else {
            animalsDict[animalKey] = [animal]
        }
    }
    animalSelectionTitles = [String] (animalsDict.keys)
    animalSelectionTitles.sort({ $0 < $1})
    animalSelectionTitles.sort( { (s1:String, s2:String) -> Bool in
        return s1 < s2
    })
}

override func viewDidLoad() {
    super.viewDidLoad()

    createAnimalDict()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

// MARK: - Table view data source

override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    // Return the number of sections.
    return animalSelectionTitles.count
}

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int, titleForHeaderInSection section:Int)  -> String? {
    // Return the number of rows in the section.
    return animalSelectionTitles[section]

}


override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! UITableViewCell

    // Configure the cell...
    cell.textLabel?.text = animals[indexPath.row]

    // Convert the animal name to lower case and 
    // then replace all occurences of a space with an underscore
    let imageFilename = animals[indexPath.row].lowercaseString.stringByReplacingOccurrencesOfString(" ", withString: "_", options: nil, range: nil)
    cell.imageView?.image = UIImage(named: imageFilename)

    return cell
}

Answer 1

两件事：

1）

你应该改变你的行

let animalKey = animal.substringFromIndex(advance(animal.startIndex, 1))

目前它是来自第二个字符的子字符串，这意味着对于输入Black Swan，则animalKey将等于lack Swan。相反，您应该使用以下行：

let animalKey = animal.substringToIndex(advance(animal.startIndex, 1))

2）

UITableViewDataSource Protocol中没有名为tableView:numberOfRowsInSection:titleForHeaderInSection的方法。相反，您需要将其拆分为以下两种方法：

override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    let title = animalSelectionTitles[section]
    return animalsDict[title]!.count
}

override func tableView(tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
    return animalSelectionTitles[section]
}

更新1：

在tableView:cellForRowAtIndexPath中，您还应该更新动物名称的检索，以反映字典中存储的内容，如下所示：

// Configure the cell...
let secTitle = animalSelectionTitles[indexPath.section]
let animalName = animalsDict[secTitle]![indexPath.row]
cell.textLabel?.text = animalName

TableView错误：titleForHeaderInSection / Swift

1 个答案: