Swift 简单控件示例：活动指示器UIActivityIndicatorView

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//
//  ViewController.swift
//  UIActivityIndicatorViewSample
//
//  Created by jinnchang on 15/4/2.
//  copyright (c) 2015年 Jinn Chang. All rights reserved.
//

import UIKit

class ViewController: UIViewController {
    
    var activityIndicatorView: UIActivityIndicatorView!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view,typically from a nib.
        
        let button1 = UIButton.buttonWithType(.System) as UIButton
        button1.frame = CGRectMake(30,50,self.view.frame.size.width - 60,100)
        button1.setTitle("显示",forState: .normal)
        button1.addTarget(self,action: "buttonAction:",forControlEvents: .TouchUpInside)
        button1.tag = 1
        
        let button2 = UIButton.buttonWithType(.System) as UIButton
        button2.frame = CGRectMake(30,150,100)
        button2.setTitle("隐藏",forState: .normal)
        button2.addTarget(self,forControlEvents: .TouchUpInside)
        button2.tag = 2
        
        activityIndicatorView = UIActivityIndicatorView(activityIndicatorStyle: .White)
        activityIndicatorView.frame = CGRectMake(self.view.frame.size.width/2 - 50,250,100,100)
        activityIndicatorView.color = UIColor.blackColor()
        
        self.view.addSubview(button1)
        self.view.addSubview(button2)
        self.view.addSubview(activityIndicatorView)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // dispose of any resources that can be recreated.
    }

    /// 按钮响应事件
    func buttonAction(sender: UIButton) {
        let num = sender.tag
        switch num {
        case 1:
            activityIndicatorView.startAnimating()
        case 2:
            activityIndicatorView.stopAnimating()
        default:
            break
        }
    }

}