【问题标题】:append data retrieved from API for loop to array将从 API for 循环检索到的数据附加到数组
【发布时间】:2019-01-18 14:39:31
【问题描述】:

我在使用 for 循环将从 API 检索到的数据附加到数组时遇到问题。我正在尝试使用数组将表格视图中的单元格出列。我编辑了问题以符合提供的答案,但在 numberofrowsinsection(放置整数以检查更多错误)和 cellforrowat 处收到错误。

这是视图控制器中的代码:

  class BusinessesViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

var businesses: [Business] = []

@IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
    super.viewDidLoad()
    Business.searchWithTerm(term: "Restaurants", sort: .distance, categories: nil) { (businesses, error) in
        self.businesses = businesses!


    }
    self.tableView.reloadData()
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
     return businesses.count

}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Business") as! SelectTableViewCell
    let business = businesses[indexPath.row]
    cell.BusinessName.text = business.name

    return cell
}


}

这是返回的当前控制台打印输出

["sort_by": distance, "open_now": 0, "term": Restaurants, "location": 37.785771,-122.406165]
Optional([<Decided.Business: 0x600000123520>, <Decided.Business: 0x600000123700>, <Decided.Business: 0x600000123c00>, <Decided.Business: 0x600000123ca0>, <Decided.Business: 0x600000123b60>, <Decided.Business: 0x604000124060>, <Decided.Business: 0x6040001241a0>, <Decided.Business: 0x604000124240>, <Decided.Business: 0x6040001244c0>, <Decided.Business: 0x604000124560>, <Decided.Business: 0x604000124600>, <Decided.Business: 0x600000123f20>, <Decided.Business: 0x6040001246a0>, <Decided.Business: 0x604000124740>, <Decided.Business: 0x6040001247e0>, <Decided.Business: 0x604000124880>, <Decided.Business: 0x600000124240>, <Decided.Business: 0x6000001242e0>, <Decided.Business: 0x600000124380>, <Decided.Business: 0x6000001244c0>])

这是我正在使用的模型:

import UIKit

class Business: NSObject {
let name: String?
let address: String?
let imageURL: URL?
let categories: String?
let distance: String?
let ratingImage: UIImage?
let reviewCount: NSNumber?

init(dictionary: NSDictionary) {
    name = dictionary["name"] as? String

    let imageURLString = dictionary["image_url"] as? String
    if imageURLString != nil {
        imageURL = URL(string: imageURLString!)
    } else {
        imageURL = nil
    }

    let location = dictionary["location"] as? NSDictionary
    var address = ""
    if location != nil {
        let addressArray = location!["display_address"] as? NSArray
        if addressArray != nil {
            if addressArray!.count > 0 {
                address = addressArray![0] as! String
            }
            if addressArray!.count > 1 {
                address += ", " + (addressArray![1] as! String)
            }
        }
    }
    self.address = address

    let categoriesArray = dictionary["categories"] as? [NSDictionary]
    if categoriesArray != nil {
        var categoryNames = [String]()
        for category in categoriesArray! {
            let categoryName = category["title"] as! String
            categoryNames.append(categoryName)
        }
        categories = categoryNames.joined(separator: ", ")
    } else {
        categories = nil
    }

    let distanceMeters = dictionary["distance"] as? NSNumber
    if distanceMeters != nil {
        let milesPerMeter = 0.000621371
        distance = String(format: "%.2f mi", milesPerMeter * distanceMeters!.doubleValue)
    } else {
        distance = nil
    }

    let rating = dictionary["rating"] as? Double
    if rating != nil {
        switch rating {
            case 1:
                self.ratingImage = UIImage(named: "stars_1")
                break
            case 1.5:
                self.ratingImage = UIImage(named: "stars_1half")
                break
            case 2:
                self.ratingImage = UIImage(named: "stars_2")
                break
            case 2.5:
                self.ratingImage = UIImage(named: "stars_2half")
                break
            case 3:
                self.ratingImage = UIImage(named: "stars_3")
                break
            case 3.5:
                self.ratingImage = UIImage(named: "stars_3half")
                break
            case 4:
                self.ratingImage = UIImage(named: "stars_4")
                break
            case 4.5:
                self.ratingImage = UIImage(named: "stars_4half")
                break
            case 5:
                self.ratingImage = UIImage(named: "stars_5")
                break
            default:
                self.ratingImage = UIImage(named: "stars_0")
                break
        }
    } else {
        self.ratingImage = UIImage(named: "stars_0")
    }

    reviewCount = dictionary["review_count"] as? NSNumber
}

class func businesses(array: [NSDictionary]) -> [Business] {
    var businesses = [Business]()
    for dictionary in array {
        let business = Business(dictionary: dictionary)
        businesses.append(business)
    }
    return businesses
}

class func searchWithTerm(term: String, completion: @escaping ([Business]?, Error?) -> Void) {
    _ = YelpClient.sharedInstance.searchWithTerm(term, completion: completion)
}

class func searchWithTerm(term: String, sort: YelpSortMode?, categories: [String]?, completion: @escaping ([Business]?, Error?) -> Void) -> Void {
    _ = YelpClient.sharedInstance.searchWithTerm(term, sort: sort, categories: categories, openNow: false, completion: completion)
}
}

【问题讨论】:

  • 你能详细说明一下吗?编译错误或行为
  • 控制台打印输出显示行为,当我附加相同的数据时由于循环重新出现,我不知道如何解决这个问题。例如 Hot Dog Stand 13 Hot Dog StandAnnie 的 Hot Dog Cart 33。每次打印输出都会重复“Hot Dog Stand”。我希望数据打印一次,包含所有名称和正确的名称数量。
  • 看起来你正在遍历一个数组并在每次迭代时调用 print 。尝试将你的 print 语句移到 for 循环之外
  • 这是控制台更新代码的新打印输出
  • ["sort_by": distance, "open_now": 0, "term": Restaurants, "location": 37.785771,-122.406165] Hot Dog StandAnnie's Hot Dog CartJohn's GrillAnnie's Hot Dogs & PretzelsTads Steak RestaurantBoudin Bakery & CafeDirty HabitConfetti Cafe at Macy's Wolfgang Puck PizzaBoudin Bakery & CafeKing Of Thai Noodle HouseSorabol Korean RestaurantBluestem BrasserieSF BistroCaffe MioWishboneLobster MEPasta MotoFire of Brazil ExpressTap415 328

标签: swift xcode api loops append


【解决方案1】:

您的主要错误是您将Names 声明为String

在添加Hot Dog Stand 之后,表格视图将创建 13 个单元格,因为字符串有 13 个字符,在 numberOfRows 中返回。

你可能想要

 Business.searchWithTerm(term: "Restaurants", sort: .distance, categories: nil) { (businesses, error) in
       if let error = error { print(error); return }
       self.businesses = businesses!
       DispatchQueue.main.async {
           self.tableView.reloadData()
       }
 }

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

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Business") as! SelectTableViewCell
    let business = businesses[indexPath.row]
    cell.BusinessName.text = business.name

    return cell
}

并删除Names 属性

【讨论】:

  • 谢谢,但没有用我编辑了问题以反映您的更改
  • @OmarAl-Eisa 您仍在完成块外调用self.tableView.reloadData()。检查@vaidan 如何在完成块内调用。
  • 永远不要硬编码numberOfRows的返回值,不要返回16。返回businesses.count。请仔细阅读我的建议。你必须在闭包中调用reloadData() in。我还添加了一个调度块来重新加载主线程上的表视图。
  • @vadian ok 应用程序不再崩溃,但它也不再从 api fetch 返回任何数据
  • 您是否已将reloadData() 移入关闭?根据您编辑的代码,您没有。考虑searchWithTerm异步工作
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