单元格imageView中的圆形图像以及如何调整它的大小？

Question

我有一个带有标识符“Cell”的 ViewController tableView。这是我的代码：

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell

    var url = NSURL(string: postCover[indexPath.row])
    let data = NSData(contentsOfURL: url!) //make sure your image in this url does exist, otherwise unwrap in a if let check

    cell.imageView?.contentMode = .ScaleAspectFit
    cell.imageView?.clipsToBounds = true

    cell.imageView?.image = UIImage(data: data!)
    cell.textLabel?.text = postTitle[indexPath.row]

    cell.imageView?.layer.cornerRadius =  20
    cell.imageView?.layer.masksToBounds = true;

    return cell
}

所以，cornerRadius 有效，但问题之一是我在单元格中的图像 (cell.imageView?.image) 高度等于行高，我无法更改此单元格图像的高度和宽度。

当我尝试时

cell.imageView?.frame.size.width = 100

没有任何变化。谁知道，有什么问题？

由于我无法控制图像的高度和宽度，我得到的结果是带有边框半径的矩形，但我想要一个正方形（w：100，h：100）。

Answer 1

您可以使用此扩展来裁剪图像的最长边并返回一个平方的 UIImage：

extension UIImage {
    var squared: UIImage {
        let square = size.width < size.height ? CGSize(width: size.width, height: size.width) : CGSize(width: size.height, height: size.height)
        let imageView = UIImageView(frame: CGRect(origin: CGPoint(x: 0, y: 0), size: square))
        imageView.contentMode = UIViewContentMode.ScaleAspectFill
        imageView.image = self
        UIGraphicsBeginImageContext(imageView.bounds.size)
        imageView.layer.renderInContext(UIGraphicsGetCurrentContext())
        let result = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return result
    }
    var circle: UIImage {
        let square = size.width < size.height ? CGSize(width: size.width, height: size.width) : CGSize(width: size.height, height: size.height)
        let imageView = UIImageView(frame: CGRect(origin: CGPoint(x: 0, y: 0), size: square))
        imageView.contentMode = UIViewContentMode.ScaleAspectFill
        imageView.image = self
        imageView.layer.cornerRadius = square.width/2
        imageView.layer.masksToBounds = true
        UIGraphicsBeginImageContext(imageView.bounds.size)
        imageView.layer.renderInContext(UIGraphicsGetCurrentContext())
        let result = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return result
    }
    func resizeToWidth(width:Int)-> UIImage {
        let imageView = UIImageView(frame: CGRect(origin: CGPoint(x: 0, y: 0), size: CGSize(width: CGFloat(width), height: CGFloat(ceil(CGFloat(width)/size.width * size.height)))))
        imageView.contentMode = UIViewContentMode.ScaleAspectFit
        imageView.image = self
        UIGraphicsBeginImageContext(imageView.bounds.size)
        imageView.layer.renderInContext(UIGraphicsGetCurrentContext())
        let result = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()
        return result
    }

}

Answer 2

您不能单独更改框架的宽度或高度。您必须设置完整的框架。在 Objective C 中，它会类似于

cell.imageView.frame = CGRectMake(cell.imageView.frame.origin.x, cell.imageView.frame.origin.y, 100, 100);

Answer 3

您不能更改任何视图的框架属性的属性。你必须提供一个全新的框架。

cell.imageView?.frame.size.width = 100 //wont work

尝试这样做 -

let rect = cell.imageView?.frame;

rect.size.width = 100;

cell.imageView?.frame = rect; //this will work