Swift - 来看看UITableView是怎么写的

//代码不难，一看就懂，不写注释了，注意UITableViewDataSource，代理方法不写会报错，里面混入了UIAlertController的使用方法，下一篇博客会对Swift中的UIAlertController方法进行说明
import UIKit
class ViewController: UIViewController,UITableViewDelegate,UITableViewDataSource {
    var tableView = UITableView()
    var dataArray = Array<String>()
    var dataArray1 = NSArray()
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        for i in 0...20 {
            dataArray.append("这是第\(i)行")
        }
        tableView = UITableView(frame: self.view.bounds, style: .Grouped)
        tableView.delegate = self
        tableView.dataSource = self
        self.view.addSubview(tableView)
    }
    func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        return 3;
    }
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return dataArray.count
    }
    func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {
        return 44
    }
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        var cell:UITableViewCell! = tableView.dequeueReusableCellWithIdentifier("cell")
        if cell == nil {
            cell = UITableViewCell(style: .Subtitle, reuseIdentifier: "cell")
        }
        cell.textLabel?.text = dataArray[indexPath.row]
        return cell
    }
    func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        let alertController = UIAlertController(title: "alertView", message: "This is a alertView and \(indexPath.row)", preferredStyle: .Alert)
        let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler:nil)
        let okAction = UIAlertAction(title: "Ok", style: .Default, handler:{
            (action: UIAlertAction!) -> Void in
            self.okAction()
        })
        alertController.addAction(cancelAction)
        alertController.addAction(okAction)
        self.presentViewController(alertController, animated: true, completion: nil)
    }
    func okAction() {
        let alertController = UIAlertController(title: "sheet", message: "This is a actionSheet", preferredStyle: .ActionSheet)
        let cancelAction = UIAlertAction(title: "Cancel", style: .Cancel, handler:nil)
        let okAction = UIAlertAction(title: "Ok", style: .Default, handler: nil)
        let okAction1 = UIAlertAction(title: "Ok1", style: .Default, handler: nil)
        alertController.addAction(cancelAction)
        alertController.addAction(okAction)
        alertController.addAction(okAction1)
        self.presentViewController(alertController, animated: true, completion: nil)
    }
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}