Question

在我的项目中，从URL下载的所有图像都显示为超大尺寸。现在，我使用Kingfisher，但是如果使用默认功能，将是相同的。

但是比例应该如下：

如果关闭从URL显示的选项并使用库中的默认图像，则比例将正确。然后得出结论，我的问题不在于约束和布局，而在于代码。也许我错了。

另外，从URL下载的图像不会立即显示或在下载后显示。长按后显示。

我的项目在哪里出错？为什么我会收到过大的图像，但长按后却无法立即显示或延迟下载？

ViewController的代码：

import UIKit
import Kingfisher

class ThirdViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

var n = 1
var title_segue = ""
var id_segue = ""
var categories_segue = ""
var tags_segue = ""
//var refresh: UIRefreshControl!

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "videoCell", for: indexPath) as! VideoNewsCell
    //print("cell: "+(self.videonews?[indexPath.item].headline)!)
    //cell.imageView!.downloadImage(from: (self.videonews?[indexPath.item].image!)!)
    let resource = ImageResource(downloadURL: URL(string: (self.videonews?[indexPath.item].image!)!)!, cacheKey: self.videonews?[indexPath.item].image!)
    cell.imageView!.kf.setImage(with: resource)
    cell.titleVideo.text = self.videonews?[indexPath.item].headline
    return cell
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    print("Launch tableview in SecondView")
    title_segue = (self.videonews?[indexPath.item].headline)!
    id_segue = (self.videonews?[indexPath.item].id)!
    categories_segue = (self.videonews?[indexPath.item].categories)!
    tags_segue = (self.videonews?[indexPath.item].tag)!
    //print(("tableView: "+(self.news?[indexPath.item].headline)!))
    performSegue(withIdentifier: "video2newsbody", sender: self)
}

func numberOfSections(in tableView: UITableView) -> Int {
    return 1
}

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

@IBOutlet weak var videoTableview: UITableView!
var videonews: [VideoNews]? = []

override func viewDidLoad() {
    super.viewDidLoad()
    getJSON()
}

@objc func getJSON(){

    let urlRequest = URLRequest(url: URL(string: "https://sportarena.com/wp-api/wp/v2/posts/?per_page=13&page=\(n)&tags=22&_embed")!)

    let task = URLSession.shared.dataTask(with: urlRequest) { (data,response,error) in

        if error != nil {
            print(error as Any)
            return
        }
        self.videonews = [VideoNews]()
        do {
            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! NSArray

            for arrayX in json as! [[String: Any]] {
                let VN = VideoNews()

                var image_url = "https://sportarena.com/wp-content/uploads/2018/09/Grey_full.png"

                let tag0 = arrayX["tags"] as? NSArray

                let categories0 = arrayX["categories"] as? NSArray
                let title0 = arrayX["title"] as? [String: Any]
                let embedded = arrayX["_embedded"] as? [String: Any]
                let featuredmedia0 = embedded?["wp:featuredmedia"] as? NSArray
                let featuredmedia = featuredmedia0?[0] as? [String: AnyObject]
                let media_details = featuredmedia?["media_details"]
                let sizes0 = media_details?["sizes"] as? [String: AnyObject]
                let sizes = sizes0?["video-small"]
                if (featuredmedia0 != nil || featuredmedia != nil || media_details != nil || sizes0 != nil || sizes != nil) {
                    image_url = sizes?["source_url"] as! String
                }

                if let ID = arrayX["id"],
                    let date = arrayX["date"],
                    let title = title0!["rendered"] as? String,
                    let categories = categories0?[0],
                    let tags = tag0?[0] {
                    VN.headline = Html().convert(from: title)
                    VN.image = image_url
                    VN.id = "\(ID)"
                    VN.date = date as? String
                    VN.categories = "\(categories)"
                    VN.tag = "\(tags)"
                }
                self.videonews?.append(VN)
            }
            DispatchQueue.main.async {
                self.videoTableview.reloadData()
            }
        } catch let error {
            print(error)
        }
    }
    task.resume()
}

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

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if (segue.identifier == "video2newsbody") {
        let NewsBodyController = segue.destination as! NewsBody
        NewsBodyController.title_news = title_segue
        NewsBodyController.id_news = id_segue
        NewsBodyController.categories_news = categories_segue
        NewsBodyController.tags_news = tags_segue
    }
}


}

Answer 1

似乎与绘制周期有关，请确保图像视图的内容被裁剪到绘制矩形的边界：然后，您还可以指定如何使用contentMode属性绘制内容，因为默认情况下是通过更改内容的纵横比来缩放内容以适合其自身的大小。有关更多信息：https://developer.apple.com/documentation/uikit/uiview/contentmode

除了显示（或绘制）从Kingfisher获得的图像外，您还需要告诉系统这样做，一种选择是在使单元出队时将imageView中的图像设置为nil，然后设置新图像，这将调用绘图系统。

 let cell = tableView.dequeueReusableCell....
//print("cell: "+(self.videonews?[indexPath.item].headline)!)
//cell.imageView!.downloadImage(from: (self.videonews?[indexPath.item].image!)!)

   cell.imageView.image = nil //option 1

let resource = ImageResource(downloadURL: URL(string: (self.videonews?[indexPath.item].image!)!)!, cacheKey: self.videonews?[indexPath.item].image!)
cell.imageView!.kf.setImage(with: resource)
cell.titleVideo.text = self.videonews?[indexPath.item].headline

    // option 2 : cell.imageView.setNeedsDisplay()

return cell

下载的图像显示为超大尺寸

1 个答案: