代码来源  cocoachina推荐源码  26日

上面这些是一些基本的设置，然后提前补充几个知识点！

类后面的!作用是强制类型转换

NSCoder是一个抽象类，是字节流的抽象类，我们可以把数据写入一个coder也可以从coder中读出数据！

as也可以类型为类型转换

Swift中sort函数有两种用法，在编译器中输入sort查看帮助文档有相信解释！

建议观看Swift language 函数章节

import UIKit

class ViewController: UITableViewController {
    
    var familyNames : Array<String> = []
    var fonts : Dictionary<String, String[]> = [:]

    
    init(coder aDecoder: NSCoder!)
    {
        super.init(coder: aDecoder)
        
        let unsortedFamilyNames = UIFont.familyNames() as String[]
        familyNames = sort(unsortedFamilyNames)
        
        for familyName in familyNames
        {
            let unsortedFontNames = UIFont.fontNamesForFamilyName(familyName) as String[]
            fonts[familyName] = sortFontNames(unsortedFontNames)
        }
    }
    
    override func numberOfSectionsInTableView(tableView: UITableView!) -> Int
    {
        return countElements(familyNames)
    }
    
    override func tableView(tableView: UITableView!, numberOfRowsInSection section: Int) -> Int
    {
        let key = familyNames[section]
        let array = fonts[key]
        return array!.count
    }
    
    override func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell!
    {
        let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as UITableViewCell
        
        let key = familyNames[indexPath.section]
        let array = fonts[key]
        let fontName = array![indexPath.row]
        
        cell.textLabel.text = fontName
        cell.textLabel.font = UIFont(name:fontName, size: UIFont.systemFontSize())
        
        return cell
    }
    
    override func tableView(tableView: UITableView!, heightForRowAtIndexPath indexPath: NSIndexPath!) -> CGFloat
    {
        let key = familyNames[indexPath.section]
        let array = fonts[key]
        let fontName = array![indexPath.row]
        
        let label = UILabel(frame: CGRectMake(0, 0, 280, 200))
        label.text = fontName
        label.font = UIFont(name: fontName, size: UIFont.systemFontSize())
        label.sizeToFit()
        
        return max(label.font.lineHeight + label.font.ascender + -label.font.descender, 44)
    }
    
    /* This function is necessary because fonts shouldn't always be sorted alphabetically.
    For example, ArialMT should come before Arial-BoldItalicMT,
    but if we sort alphabetically, it doesn't. */
    /* 这个函数是必要的,因为字体不总是按字母顺序排序。
    例如,ArialMT应该Arial-BoldItalicMT之前,
    但是如果我们按字母顺序排序,ArialMT就不会在Arial-BoldItalicMT之前。*/
    func sortFontNames(array: String[]) -> String[]
    {
        return sort(array, { (s1: String, s2: String) -> Bool in
            // if s1 doesn't contain a hyphen, it should appear before s2
            let count1 = countElements(s1.componentsSeparatedByString("-"))
            if count1 == 1
            {
                return true
            }
            
            // if s2 doesn't contain a hyphen, it should appear before s1
            let count2 = countElements(s2.componentsSeparatedByString("-"))
            if count2 == 1
            {
                return false
            }
            
            // otherwise, a normal string compare will be fine
            return s1 > s2
            })
    }

}