DispatchGroupの.leaveと.notifyを使用して取得したデータを表示（楽天API）

今回の内容

• 最近、DispatchQueue.main.asyncAfterをよく使ってましたが、データの取得が終わった時にUITableViewに表示させる為にDispatchGroupの.leaveと.notifyを使用してます。

コード

Model

GetDataDetailModel

struct GetDataDetailModel{

    let mediumImageURL:String?
    let itemName:String?
    let itemPrice:Int?
    let itemCaption:String?
}

AlamofireProcess

import Alamofire
import SwiftyJSON

class AlamofireProcess{

    public var getDataResultArray = [GetDataDetailModel]()
    private var keyword:String?

    init(getKey:String?){

        keyword = getKey
    }
}

extension AlamofireProcess{

    public func getItemDetailData(completion: @escaping() -> Void){

        guard let key = keyword else { return }

        let apiKey = "https://app.rakuten.co.jp/services/api/IchibaItem/Search/20170706?format=json&keyword=\(key.urlEncoded)&applicationId=作成したアプリID"

        AF.request(apiKey, method: .get, parameters: nil, encoding: JSONEncoding.default).responseJSON {[self] response in

            switch response.result{

            case .success:

                let jsonDetail = JSON(response.data as Any)
                getDataResultArray = []

                for dataCount in 0..<jsonDetail["Items"].count{

                    if let getMediumImageURL = jsonDetail["Items"][dataCount]["Item"]["mediumImageUrls"][0]["imageUrl"].string,
                       let getItemName = jsonDetail["Items"][dataCount]["Item"]["itemName"].string,
                       let getItemPrice = jsonDetail["Items"][dataCount]["Item"]["itemPrice"].int,
                       let getItemCaption = jsonDetail["Items"][dataCount]["Item"]["itemCaption"].string{

                        getDataResultArray.append(GetDataDetailModel(mediumImageURL: getMediumImageURL,
                                                                     itemName: getItemName,
                                                                     itemPrice: getItemPrice,
                                                                     itemCaption: getItemCaption))
                    }

                }
                completion()

            case .failure:

                completion()
            }
        }
    }
}

extension String{

    var urlEncoded:String{

        let charset = CharacterSet.alphanumerics.union(.init(charactersIn: "/?-._~"))
        let remove = removingPercentEncoding ?? self

        return remove.addingPercentEncoding(withAllowedCharacters: charset) ?? remove
    }
}

View

Main.storyboard

SearchResultCell

SearchResultCell

import UIKit

class SearchResultCell: UITableViewCell {

    @IBOutlet weak var mediumImageView: UIImageView!
    @IBOutlet weak var itemNameLabel: UILabel!
    @IBOutlet weak var itemPriceLabel: UILabel!
    @IBOutlet weak var itemCaptionView: UITextView!

    override func awakeFromNib() {
        super.awakeFromNib()

    }

    override func setSelected(_ selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)


    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)

    }

    override func prepareForReuse() {
        super.prepareForReuse()

        mediumImageView.image = UIImage(named: "")
        itemNameLabel.text = ""
        itemPriceLabel.text = ""
        itemCaptionView.text = ""
    }
}

Controller

import UIKit
import SDWebImage

class ViewController: UIViewController {

    @IBOutlet weak var searchTextField: UITextField!
    @IBOutlet weak var searchButton: UIButton!
    @IBOutlet weak var resultTableView: UITableView!

    private let alamofireProcess = AlamofireProcess(getKey: nil)

    private let dispatchGroup = DispatchGroup()
    private let dispachQueue = DispatchQueue(label: "alamofire",attributes: .concurrent)

    private var cellContentsArray = [GetDataDetailModel]()

    override func viewDidLoad() {
        super.viewDidLoad()

        resultTableView.register(UINib(nibName: "SearchResultCell", bundle: nil), forCellReuseIdentifier: "ItemDetailCell")
        resultTableView.delegate = self
        resultTableView.dataSource = self

    }

    @IBAction func search(_ sender: UIButton) {

        let afProcess = AlamofireProcess(getKey: searchTextField.text)

        dispatchGroup.enter()
        dispachQueue.async {[self] in

            afProcess.getItemDetailData {

                self.dispatchGroup.leave()
            }
        }

        dispatchGroup.notify(queue: .main){ [self] in

            cellContentsArray = afProcess.getDataResultArray
            print(cellContentsArray)
            resultTableView.reloadData()
        }
    }

}

extension ViewController:UITableViewDelegate{

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

        return tableView.frame.height / 2.4
    }
}


extension ViewController:UITableViewDataSource{

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

        return cellContentsArray.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "ItemDetailCell", for: indexPath) as! SearchResultCell

        cell.mediumImageView.sd_setImage(with: URL(string: cellContentsArray[indexPath.row].mediumImageURL!), completed: nil)
        cell.itemNameLabel.text = cellContentsArray[indexPath.row].itemName
        cell.itemPriceLabel.text = String(cellContentsArray[indexPath.row].itemPrice!) + "円"
        cell.itemCaptionView.text = cellContentsArray[indexPath.row].itemCaption

        return cell
    }
}

終わり

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