如何计算String的高度？

Question

我试图调整单元格高度调整大小以适应UILabel文本,但它不工作..

var mySize = CGFloat()
    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! cellView

        cell.myLabel.text = self.items[indexPath.item]
        cell.myLabel.bounds.size.height = self.mySize

        cell.backgroundColor = UIColor.yellowColor()

        return cell
    }

    func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
        // handle tap events
        print("You selected cell #\(indexPath.item)!")
    }

    func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAtIndexPath indexPath: NSIndexPath) -> CGSize {

        func heightForLabel(text:String, font:UIFont, width:CGFloat) -> CGFloat
        {
            let label:UILabel = UILabel(frame: CGRectMake(0, 0, width, CGFloat.max))
            label.numberOfLines = 0
            label.lineBreakMode = NSLineBreakMode.ByWordWrapping
            label.font = font
            label.text = items[indexPath.row]

            label.sizeToFit()
            return label.frame.height
        }

        let font = UIFont(name: "Helvetica Neue", size: 30)
        let detailHeight = heightForLabel(items[indexPath.row], font: font!, width: UIScreen.mainScreen().bounds.size.width)

        self.mySize = detailHeight

        return CGSizeMake(UIScreen.mainScreen().bounds.size.width, 358 + detailHeight)
    }

有什么建议在这做什么？我应该用另一种方式吗？请,我需要帮助..问题是UILabel文本设置在cellForItemAtIndexPath,并且items是一个字符串数组.

这是我的项目文件,如果有人注意看看它:http: //www.filedropper.com/test_37

Answer 1

为什么不在 ObjC 中尝试这个

 [text boundingRectWithSize:CGSizeMake(maxWidth, maxHeight)
                                  options:NSStringDrawingUsesLineFragmentOrigin
                               attributes:nil context:nil]

这将给出 CGRect. 从中获取高度。在属性参数中设置字体大小等。

更新

代替这个

let detailHeight = heightForLabel(items[indexPath.row], font: font!, width: UIScreen.mainScreen().bounds.size.width)

用这个

let height = items[indexPath.row].boundingRectWithSize(CGSizeMake(CGFloat.max,UIScreen.mainScreen().bounds.size.width), options: .UsesLineFragmentOrigin, attributes: [NSFontAttributeName: font!], context: nil).size.height

希望这可以帮助

Answer 2

你可以这样做，但我以不同的方式实现了它。这是您可以执行此操作的代码示例。

 let desiredWidth: CGFloat = tableView.bounds.size.width
 let label: UILabel = UILabel()

 let desiredString = "Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. It has survived not only five centuries, but also the leap into electronic typesetting, remaining essentially unchanged."

 label.text = desiredString
 label.numberOfLines = 0;
 label.lineBreakMode = NSLineBreakMode.ByWordWrapping
 let size: CGSize = label.sizeThatFits(CGSizeMake(desiredWidth, CGFloat.max))

 print("Label height you can set to your cell: \(size.height)")