为啥当我滚动浏览 UITableView 时图像会不断调整大小？

Posted 2023-03-04

【中文标题】为啥当我滚动浏览 UITableView 时图像会不断调整大小？

【英文标题】：Why do the images keep on resizing as I scroll through my UITableView?为什么当我滚动浏览 UITableView 时图像会不断调整大小？

【发布时间】：2018-01-13 05:56:58

【问题描述】：

所有图像都可以正常加载并显示其宽度与手机相同，其高度由照片的纵横比决定。最初除了第三张照片之外的所有照片都以这种方式加载，在滚动出图像视图并返回后，图像会正确调整大小，但最初图像只是在 scaleaspectFill 中，没有正确的宽度和高度。

import UIKit
import Firebase
import FirebaseStorageUI

class TableViewController: UITableViewController 
var images:[UIImage]! = [#imageLiteral(resourceName: "rininger_2.jpg")]
var imageURLS:[String] = [String]()
var listener:ListenerRegistration?

override func viewDidLoad() 
    super.viewDidLoad()

    /////////
    listener = Firestore.firestore().collection("Posts").addSnapshotListener
        querySnapshot, error in
        guard let snapshot = querySnapshot else 
            print("Error fetching snapshots: \(error!)")
            return
        
        snapshot.documentChanges.forEach  diff in
            if (diff.type == .added) 
                print("New data: \(diff.document.data())")
            
            if (diff.type == .modified) 
                print("Modified city: \(diff.document.data())")
            
            if (diff.type == .removed) 
                print("Removed city: \(diff.document.data())")
            
            // self.numberOfRows = snapshot.count
            // Parse each post


            //self.labels.append(newLabel)


            //Update TableView
            DispatchQueue.main.async 
                //This would reload everything creating a flash
                //self.tableView.reloadData()
                guard let newImageURL = diff.document.data()["imageDownloadURL"] as? String else
                    print("Failed to get image download URL")
                    return
                
                //let newLabel = Post(snapshot:diff.document)
                print("downloadURL: \(newImageURL)")
                self.imageURLS.insert(newImageURL, at: 0)
                let indexPath = IndexPath(row: 0, section: 0)
                self.tableView.insertRows(at: [indexPath], with: .top)

            
        
    /////////
    



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


// MARK: - Table view data source

override func numberOfSections(in tableView: UITableView) -> Int 
    // #warning Incomplete implementation, return the number of sections
    return 1


override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int 
    // #warning Incomplete implementation, return the number of rows
    return imageURLS.count



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

    // Configure the cell...

    ///////////////////////
        let downloadURL = URL(string: imageURLS[indexPath.row])

            //cell.cellImageView.sd_setImage(with: downloadURL, completed:nil)
            //cell.cellImageView.image = self.images[indexPath.row]
    do
        let imageData = try Data(contentsOf: URL(string:(imageURLS[indexPath.row]))!)
        cell.cellImageView.image = UIImage(data: imageData)
    
    catch
        print("unable to load data: \(error)")
    
            cell.cellImageView.contentMode = .scaleAspectFit
            let aspectRatio = Float((cell.cellImageView?.image?.size.width)!/(cell.cellImageView?.image?.size.height)!)
            tableView.rowHeight = CGFloat(Float(UIScreen.main.bounds.width)/aspectRatio)

    ///////////////////////
    return cell
 

【参考方案1】：

确保UIImageView 上的clipsToBounds 属性设置为true。

【讨论】：

感谢您的回复，不幸的是它不是那么简单，我已尝试将约束设置为对所有范围都归零。我相信它与队列有关。