Question

//Parsing JSON Oké
    let parsedData : [String:AnyObject]
    do{
        parsedData = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String:AnyObject]
        guard let results = parsedData["results"] as? [[String:AnyObject]] else {
            print("There is a problem related to results fetch"); return }
        for res in results {

            var dataMi : Data!
            //For the image data
            let urlOfthePic = URL(string: "https://image.tmdb.org/t/p/w92\(res["backdrop_path"]!)")
            let downLoadPicTask = URLSession.shared.dataTask(with: urlOfthePic!, completionHandler: { (data, res, err) in
                guard let data = data else {print("second"); return}
                dataMi = data
                self.mov.movImage = UIImage(data: dataMi)!
                print(dataMi)
            });downLoadPicTask.resume()
            print("2:", dataMi)
            //Error is occured because of the "nil" 
            //self.mov.movImage = UIImage(data:dataMi)!

            self.mov.movTitle = res["original_title"] as! String
            self.mov.desctiption = res["overview"] as! String
            self.movResult.append(self.mov)
            self.resultCount = results.count
        }
        DispatchQueue.main.async() {
            self.myCollectionView.reloadData()
        }
    }catch{
        print("Error is occured because of the Json Serialization")
    }
};task.resume()

关于下载顺序的问题

此代码运行良好，但是下载图片存在问题，因为图片网址取决于json网址。当我下载其他数据时，我想下载图像，如电影标题，电影描述等。

代码运行时：

print(dataMi)

返回数据，但......

print("2:", dataMi)

返回nil。那么我该怎样做才能正确运行该部分？ 因为它也会导致错误，我无法在单元格中设置我的imageview

 //Error is occured because of the "nil" 
 //self.mov.movImage = UIImage(data:dataMi)!

Console Screen Shot

Answer 1

第一个问题，

let downLoadPicTask = URLSession.shared.dataTask(with: urlOfthePic!, completionHandler: { (data, res, err) in
    guard let data = data else {print("second"); return}
    dataMi = data
    self.mov.movImage = UIImage(data: dataMi)!
    print(dataMi)
});downLoadPicTask.resume()
print("2:", dataMi)

这段代码是异步运行的，因此print("2:", dataMi)会立即执行，print(dataMi)将在dataTask完成后执行。因此，如果您立即打印dataMi，当然会nil。 dataTask完成后，dataMi不是nil包含数据。

对于您的第二个问题，请检查您的urlOfthePic是否正确且可访问。

Answer 2

我自己解决了这个问题：D当我试图解决这个问题时，我学到了太多的工作人员;我学到的最好的事情是：＆＃34;不要放弃......＆＃34; 一段时间后我写的代码：

我覆盖了我的数据模型并将poster_path添加到我的Movie struct
通过我的JSON流程，我获得了API中的值
movies数组中填充了更新的Movie个对象
我在第二部分创建了一个URL，它是源代码中的func

感谢Dispatch＆lt; 3我使用零延迟 填充了集合视图

override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(true)
//MARK: JSON
//get popular films for moviescontroller page

var components = URLComponents()

components.scheme = Constanst.API.ApiSchema
components.host = Constanst.API.ApiHost
components.path = Constanst.API.ApiPath
components.path = components.path + Constanst.API.Discover + Constanst.API.Movies
components.queryItems = [URLQueryItem(name: "api_key", value: Constanst.API.ApiKey), URLQueryItem(name: "language", value: "en-US"), URLQueryItem(name: "sort_by", value: "popularity.desc"), URLQueryItem(name: "include_adult", value: "false"), URLQueryItem(name: "include_video", value: "false"),URLQueryItem(name: "page", value: "1")]


//Url OKé
let url = components.url

//Config OKé
let request = NSMutableURLRequest(url: url!, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0)
request.httpMethod = "GET"

//Request OKé
let task = URLSession.shared.dataTask(with: request as URLRequest) { (data, response, error) in
    guard (error == nil) else{
        print("Error is occures: \(error!)")
        return
    }
    guard let statusCode = (response as? HTTPURLResponse)?.statusCode, statusCode<300 && statusCode>199 else {
        print("There is an error related to your response")
        return
    }
    guard let data = data else {
        print("There is no data")
        return
    }

    //Parsing JSON Oké
    let parsedData : [String:AnyObject]
    do{
        parsedData = try JSONSerialization.jsonObject(with: data, options: .allowFragments) as! [String:AnyObject]
        guard let results = parsedData["results"] as? [[String:AnyObject]] else { print("There is a problemGa");return}
        for res in results {
            self.movie.movTitle = res["original_title"] as! String
            self.movie.desctiption = res["overview"] as! String
            self.movie.posterPath = res["poster_path"] as! String
            self.movies.append(self.movie)
        }
    }catch{
        print("Error is occured because of the Json Serialization")
    }
    DispatchQueue.main.async {
        self.myCollectionView.reloadData()
    }
};task.resume()

func collectionView（_ collectionView：UICollectionView，cellForItemAt indexPath：IndexPath） - ＆gt; UICollectionViewCell {

let cell = myCollectionView.dequeueReusableCell(withReuseIdentifier: cellID, for: indexPath) as! myCollectionViewCell
cell.setUpConstraints()

    cell.movieTitle.text = movies[indexPath.row].movTitle
    cell.desc.text = movies[indexPath.row].desctiption
    cell.movieImage.image = movies[indexPath.row].movImage

let task = URLSession.shared.dataTask(with: URLRequest(url:URL(string:"https://image.tmdb.org/t/p/w92\(movies[indexPath.row].posterPath)")!), completionHandler: { (data, res, err) in
    guard let imageData = data else {return}
    guard (err == nil) else {print(err!); return}
    DispatchQueue.main.async {
        cell.movieImage.image = UIImage(data: imageData)
    }
});task.resume()





    return cell

如何下载图像以填充我的collectionviewcell JSON？

2 个答案: