单击 tableview 单元格时，将图像传递到另一个视图。 图片取自 json 数据并用 alamofire 初始化

Question

我正在从 url 获取 json 数据并将其显示在 tableview 中。 单击 tableview 单元格时，我想在 tableview 中将图像显示到另一个视图控制器。 我的另一个标签正在显示，但不知道如何在 tableview 的 didselectrowatindexpath 方法中为图像编写代码

我的代码：

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

    //getting hero for specified position
    let hero: Hero
    hero = heroes[indexPath.row]

    //displaying values
    cell.labelName.text = hero.name
    cell.labelTeam.text = hero.team
    cell.labelRealName.text = hero.realname
    cell.labelAppear.text = hero.firstappearance
    cell.labelPublish.text = hero.publisher

    //displaying image
    Alamofire.request(hero.imageUrl!).responseImage { (response) in
        debugPrint(response)

        if let image = response.result.value {
            cell.heroImage.image = image
        }
    }
    return cell
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

    let heroesDetails:HeroesDetailsViewController = self.storyboard?.instantiateViewController(withIdentifier: "HeroesDetailsViewController") as! HeroesDetailsViewController

    heroesDetails.strlabelTeam = heroes[indexPath.row].team
    heroesDetails.strlabelName = heroes[indexPath.row].name
    heroesDetails.strlabelAppear = heroes[indexPath.row].firstappearance
    heroesDetails.strlabelPublish = heroes[indexPath.row].publisher
    heroesDetails.strlabelRealName = heroes[indexPath.row].realname

    self.navigationController?.pushViewController(heroesDetails, animated: true)
}

我想在其中显示代码的 herodetailviewcontroller 文件：

import UIKit

class HeroesDetailsViewController: UIViewController {


    @IBOutlet weak var detailsImg: UIImageView!
    @IBOutlet weak var detailsName: UILabel!
    @IBOutlet weak var detailsRealName: UILabel!
    @IBOutlet weak var detailsTeam: UILabel!
    @IBOutlet weak var detailsAppear: UILabel!
    @IBOutlet weak var detailsPublisher: UILabel!

    var strheroImage: UIImage!
    var strlabelName: String!
    var strlabelTeam: String!
    var strlabelAppear: String!
    var strlabelPublish: String!
    var strlabelRealName: String!

    override func viewDidLoad() {
        super.viewDidLoad()

        detailsImg.image = strheroImage
        detailsName.text = strlabelName
        detailsRealName.text = strlabelRealName
        detailsTeam.text = strlabelTeam
        detailsAppear.text = strlabelAppear
        detailsPublisher.text = strlabelPublish


        // Do any additional setup after loading the view.
    }

}

我的模态文件：

class Hero{
    var name:String?
    var team:String?
    var imageUrl:String?
    var realname:String?
    var firstappearance:String?
    var publisher:String?

    init(name:String?, team:String?, imageUrl:String?, realname:String?, firstappearance:String?, publisher:String?) {
        self.name = name
        self.team = team
        self.imageUrl = imageUrl
        self.realname = realname
        self.firstappearance = firstappearance
        self.publisher = publisher
    }
}

我的 tableviewcell.swift 文件：

import UIKit

class TableViewCell: UITableViewCell {

    @IBOutlet weak var heroImage: UIImageView!
    @IBOutlet weak var labelName: UILabel!
    @IBOutlet weak var labelTeam: UILabel!
    @IBOutlet weak var labelAppear: UILabel!
    @IBOutlet weak var labelPublish: UILabel!
    @IBOutlet weak var labelRealName: UILabel!

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }

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

        // Configure the view for the selected state
    }

}

我的主 viewcontroller.swift 文件包含所有代码：

import UIKit
import Alamofire
import AlamofireImage

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource{

    //MARK: IBOUTLETS
    @IBOutlet weak var tableviewHeroes: UITableView!

    // Web API Url
    let URL_GET_DATA = "https://simplifiedcoding.net/demos/marvel/"

    // List to store Heroes
    var heroes = [Hero]()

    //implementing uirefreshcontrol to tableview
    lazy var refreshControl: UIRefreshControl = {
        let refreshControl = UIRefreshControl()
        refreshControl.addTarget(self, action: #selector(ViewController.handleRefresh), for: .valueChanged)
        refreshControl.tintColor = UIColor.init(red: 217/255, green: 133/255, blue: 199/255, alpha: 1)
        return refreshControl
    }()

    override func viewDidLoad() {
        super.viewDidLoad()

        self.tableviewHeroes.addSubview(self.refreshControl)

        //fetching data from web api
        Alamofire.request(URL_GET_DATA).responseJSON { (response) in

            //getting json
            if let json = response.result.value {

                //converting json to NSArray
                let heroesArray:NSArray = json as! NSArray

                //traversing through all elements of the array
                for i in 0..<heroesArray.count {

                        //adding heroes value to hero list
                    self.heroes.append(Hero(
                        name: (heroesArray[i] as AnyObject).value(forKey: "name") as? String, team: (heroesArray[i] as AnyObject).value(forKey: "team") as? String, imageUrl: (heroesArray[i] as AnyObject).value(forKey: "imageurl") as? String,
                        realname: (heroesArray[i] as AnyObject).value(forKey: "realname") as? String, firstappearance: (heroesArray[i] as AnyObject).value(forKey: "firstappearance") as? String, publisher: (heroesArray[i] as AnyObject).value(forKey: "publisher") as? String ))
                }

                //display data in tableview
                self.tableviewHeroes.reloadData()

            }
        }
        self.tableviewHeroes.reloadData()
    }

    func handleRefresh(refreshControl: UIRefreshControl) {
        self.tableviewHeroes.reloadData()
        refreshControl.endRefreshing()

    }

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

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

        //getting hero for specified position
        let hero: Hero
        hero = heroes[indexPath.row]


        //displaying values
        cell.labelName.text = hero.name
        cell.labelTeam.text = hero.team
        cell.labelRealName.text = hero.realname
        cell.labelAppear.text = hero.firstappearance
        cell.labelPublish.text = hero.publisher

        //displaying image
        Alamofire.request(hero.imageUrl!).responseImage { (response) in
            debugPrint(response)

            if let image = response.result.value {
                cell.heroImage.image = image
            }
        }
        return cell
    }

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {

        let heroesDetails:HeroesDetailsViewController = self.storyboard?.instantiateViewController(withIdentifier: "HeroesDetailsViewController") as! HeroesDetailsViewController

        let hero: Hero
        hero = heroes[indexPath.row]

        let image : UIImage = UIImage(data: hero.imageUrl)

        heroesDetails.strlabelTeam = heroes[indexPath.row].team
        heroesDetails.strlabelName = heroes[indexPath.row].name
        heroesDetails.strlabelAppear = heroes[indexPath.row].firstappearance
        heroesDetails.strlabelPublish = heroes[indexPath.row].publisher
        heroesDetails.strlabelRealName = heroes[indexPath.row].realname
        heroesDetails.strheroImage = image

        self.navigationController?.pushViewController(heroesDetails, animated: true)
    }


}

Answer 1

您应该使用缓存策略，而不是将下载的图像从一个 VC 传递到另一个 VC。 较大的图像可能需要一些时间来下载，用户不能在点击表格视图单元格之前等待它。 有关更多详细信息，请参阅图像缓存部分https://github.com/Alamofire/AlamofireImage

Answer 2

在你的didSelectRowAt indexPath函数中，在将图像发送到不同的 viewController 之前，先尝试将数据转换为图像，然后再发送：

首先声明一个全局图像变量：

var imageArray = [UIImage]()

然后将您从 alamofireImage 获得的图像分配给cellForRowAt indexPath函数中的此变量：

if let image = response.result.value {
        cell.heroImage.image = image
        self.imageArray.append(image)

    }

然后通过它：

heroesDetails.strlabelTeam = heroes[indexPath.row].team
heroesDetails.strlabelName = heroes[indexPath.row].name
heroesDetails.strlabelAppear = heroes[indexPath.row].firstappearance
heroesDetails.strlabelPublish = heroes[indexPath.row].publisher
heroesDetails.strlabelRealName = heroes[indexPath.row].realname

heroesDetails.strheroImage = self.imageArray[indexPath.row]

Answer 3

第一个视图控制器：

import UIKit
import Alamofire
import ObjectMapper

 var homeScreenData = [HomeDataModel]()

    func homeScreenDataAPI(){



        var params : Parameters?

        params =
            [ 
                "user_id" : id ?? 0,
            ]
        print(params as Any)

        self.view.makeToastActivity(.center)
        ApiCallWithHeader(url : “homeDataAPI” , params : params!) { responseObject, error in
            // use responseObject and error here
            print("responseObject = \(String(describing: responseObject)); error = \(String(describing: error))")

            let JSON = responseObject
            if(JSON?["status"] as? String == "success") {

                if let responseData = (JSON?["data"] as? [Dictionary<String, AnyObject>]) {

                    if let homeScreenDataValue = Mapper<HomeDataModel>().mapArray(JSONObject: responseData)
                    {

                      self.homeScreenData =  homeScreenDataValue   
                    }
                }  
            return

        }     

   func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {


        let vc = self.storyboard?.instantiateViewController(withIdentifier: "SecondViewController") as! SecondViewController
        vc.homeScreenData = homeScreenData
        vc.indexTagValue = indexPath.item
                self.navigationController?.pushViewController(vc, animated: true)
    }     

第二个视图控制器：-

            var homeScreenData = [HomeDataModel]()
            var indexTagValue = 0  

    extension HomeScreenDetailViewController : UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout {

        func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
            return homeScreenData.count
        }
   func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {


            let cell : HomeDataOtherCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: "testCollectionViewCell", for: indexPath as IndexPath) as! testCollectionViewCell
        cell.nameLabel.text = homeScreenData[indexPath.item].name

if let image = homeScreenData[indexPath.item].user_image {

                if image.contains("https://") {
                    cell.userImageView.sd_setImage(with: URL(string: image ), placeholderImage: UIImage(named: "userIcon"))

                } else {
                    let userImage = ImageURL + image
                    // userImageView.image = UIImage(named: userImage )
                    let urlString = userImage.addingPercentEncoding(withAllowedCharacters: CharacterSet.urlQueryAllowed)
                    cell.userImageView.sd_setImage(with: URL(string: urlString ?? ""), placeholderImage: UIImage(named: "userIcon"))
                }
            } else {
                cell.userImageView.image = UIImage(named: "userIcon")
            }
        return cell
}

我的应用程序中的 ImageURL 是

let ImageURL = "http://test/public/images/

Answer 4

建议传递数据模型，这样可以减少很多不必要的代码

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cellid = "testCellID"
    var cell = tableView.dequeueReusableCell(withIdentifier: cellid)
    if cell==nil {
        cell = UITableViewCell(style: .subtitle, reuseIdentifier: cellid)
    }

    let hero: Hero
    hero = heroes[indexPath.row] as! Hero
    cell?.textLabel?.text = hero.name

    let url = URL(string: hero.imageUrl ?? "")
    let data = try! Data(contentsOf: url!)
    cell?.imageView?.image = UIImage(data: data)

    return cell!
}

 func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    let hero = heroes[indexPath.row] as! Hero
    let heroesDetails = HeroesDetailsViewController()
    heroesDetails.hero = hero
    self.navigationController?.pushViewController(heroesDetails, animated: true)
}

类 HeroesDetailsViewController: UIViewController {

@IBOutlet weak var detailsImg: UIImageView!
var hero: Hero!


override func viewDidLoad() {
    super.viewDidLoad()

    let url = URL(string: hero.imageUrl ?? "")
    let data = try! Data(contentsOf: url!)
    self.detailsImg?.image = UIImage(data: data)
}

}