ios – 在Swift中的UITableViewCell中设置图像

我有一个reddit帖子列表,我想显示缩略图,如果它存在.我有它的功能,但它很麻烦.有两个主要问题：

>图像调整大小
>图像在滚动上随机播放

这是代码：

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("Post", forIndexPath: indexPath) as UITableViewCell
    let post = swarm.posts[indexPath.row]
    cell.textLabel!.text = post.title

    if(post.thumb? != nil && post.thumb! != "self") {
        cell.imageView!.image = UIImage(named: "first.imageset")
        var image = self.imageCache[post.thumb!]

        if(image == nil) {
            FetchAsync(url: post.thumb!) { data in // code is at bottom, this just drys things up
                if(data? != nil) {
                    image = UIImage(data: data!)
                    self.imageCache[post.thumb!] = image
                    dispatch_async(dispatch_get_main_queue(), {
                        if let originalCell = tableView.cellForRowAtIndexPath(indexPath) {
                            originalCell.imageView?.image = image
                            originalCell.imageView?.frame = CGRectMake(5,5,35,35)
                        }
                    })
                }
            }
        } else {
            dispatch_async(dispatch_get_main_queue(), {
                if let originalCell = tableView.cellForRowAtIndexPath(indexPath) {
                    originalCell.imageView?.image = image
                    originalCell.imageView?.frame = CGRectMake(5,5,35,35)
                }
            })
        }
    }

    return cell
}

这是应用程序加载时 – 看起来一切正常：

然后,如果我点击图像(即使你滚动),它会调整大小：

如果你向上和向下滚动,图片会变得一团糟(看看中间的帖子 – 泛型乐趣)：

我究竟做错了什么？

**图片和标题是从reddit中提取的,不是由我生成的**

编辑：承诺的FetchAsync类：

class FetchAsync {
    var url: String
    var callback: (NSData?) -> ()

    init(url: String, callback: (NSData?) -> ()) {
        self.url = url
        self.callback = callback
        self.fetch()
    }

    func fetch() {
        var imageRequest: NSURLRequest = NSURLRequest(URL: NSURL(string: self.url)!)
        NSURLConnection.sendAsynchronousRequest(imageRequest,
            queue: NSOperationQueue.mainQueue(),
            completionHandler: { response, data, error in
                if(error == nil) {
                    self.callback(data)
                } else {
                    self.callback(nil)
                }
        })
        callback(nil)
    }
}

不幸的是,这似乎是“基本”表格视图单元格的限制.我最终做的是创建一个自定义的TableViewCell.依赖Ray Wenderlich的教程,可以在这里找到： http://www.raywenderlich.com/68112/video-tutorial-table-views-custom-cells

由于代码是如此微不足道,这有点令人沮丧,但我认为从好的方面来看,这意味着它是一个“简单”的解决方案.

我的最终代码：

PostCell.swift(所有脚手架代码)

import UIKit

class PostCell: UITableViewCell {

    @IBOutlet weak var thumb: UIImageView!
    @IBOutlet weak var title: 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
    }

}

PostsController.swift

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("PostCell", forIndexPath: indexPath) as PostCell
    let post = swarm.posts[indexPath.row]
    cell.title!.text = post.title

    if(post.thumb? != nil && post.thumb! != "self") {
        cell.thumb!.image = UIImage(named: "first.imageset")
        cell.thumb!.contentMode = .ScaleAspectFit
        var image = self.imageCache[post.thumb!]

        if(image == nil) {
            FetchAsync(url: post.thumb!) { data in
                if(data? != nil) {
                    image = UIImage(data: data!)
                    self.imageCache[post.thumb!] = image
                    dispatch_async(dispatch_get_main_queue(), {
                        if let postCell = tableView.cellForRowAtIndexPath(indexPath) as? PostCell {
                            postCell.thumb!.image = image
                        }
                    })
                }
            }
        } else {
            dispatch_async(dispatch_get_main_queue(), {
                if let postCell = tableView.cellForRowAtIndexPath(indexPath) as? PostCell {
                    postCell.thumb!.image = image
                }
            })
        }
    }

    return cell
}

而我的故事板：