无法动态处理单元格大小，根据内容大小

Question

我正在尝试根据内容大小动态更改 tableView 单元格高度，但出现错误。

错误-

实际代码-

func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat
    {
        let height:CGFloat = self.calculateHeightForString(downloadTableDataa[indexPath.row] as! String)
        return height + 70.0
    }

    func calculateHeightForString(inString:String) -> CGFloat
    {
        let messageString = inString
        let attributes =  UIFont.init(name: "Roboto-Regular", size: 15)

        let attrString:NSAttributedString? = NSAttributedString(string: messageString, attributes: attributes)
        let rect:CGRect = attrString!.boundingRectWithSize(CGSizeMake(300.0,CGFloat.max), options: NSStringDrawingOptions.UsesLineFragmentOrigin, context:nil )//hear u will get nearer height not the exact value
        let requredSize:CGRect = rect
        return requredSize.height  //to include button's in your tableview

    }

Answer 1

问题是您试图将 UIFont 类型的对象传递给属性字段，而属性字段需要 [String:AnyObject] 类型的字典。这就是错误告诉你的内容。

之前

let attributes = UIFont.init(name:"Roboto-Regular", size:15.0) <---- UIFont
let attrString:NSAttributedString? = NSAttributedString(string: messageString, attributes: attributes) <---- wants a dictionary of type [String:AnyObject]

之后

let stringAttributes = [NSFontAttributeName: UIFont(name: "Roboto-Regular", size: 18.0)!] 
let attrString = NSAttributedString(string: messageString, attributes: stringAttributes)