下面是这个类的一些功能：
1.设置icon上的数字图标

    //设置主界面icon上的数字图标，在2.0中引进， 缺省为0

    [UIApplicationsharedApplication].applicationIconBadgeNumber = 4;
2.设置摇动手势的时候，是否支持redo,undo操作

    //摇动手势，是否支持redo undo操作。

   //3.0以后引进，缺省YES

    [UIApplicationsharedApplication].applicationSupportsShakeToEdit =YES;

3.判断程序运行状态

    //判断程序运行状态，在2.0以后引入

    /*

     UIApplicationStateActive,

     UIApplicationStateInactive,

     UIApplicationStateBackground

     */

   if([UIApplicationsharedApplication].applicationState ==UIApplicationStateInactive){

        NSLog(@"程序在运行状态");

    }
4.阻止屏幕变暗进入休眠状态

    //阻止屏幕变暗，慎重使用,缺省为no 2.0

    [UIApplicationsharedApplication].idleTimerDisabled =YES;

（慎重使用本功能，因为非常耗电）
5.显示联网状态

    //显示联网标记 2.0
    [UIApplicationsharedApplication].networkActivityIndicatorVisible =YES;

6.在map上显示一个地址

   NSString* addressText =@"1 Infinite Loop, Cupertino, CA 95014";

   // URL encode the spaces

    addressText =  [addressTextstringByAddingPercentEscapesUsingEncoding:NSASCIIStringEncoding];

   NSString* urlText = [NSStringstringWithFormat:@"http://maps.google.com/maps?q=%@", addressText];

    [[UIApplicationsharedApplication]openURL:[NSURLURLWithString:urlText]];

7.发送电子邮件

   NSString *recipients =@"mailto:first@example.com?cc=second@example.com,third@example.com&subject=Hello from California!";

   NSString *body =@"&body=It is raining in sunny California!";

    NSString *email = [NSStringstringWithFormat:@"%@%@", recipients, body];

    email = [emailstringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

    [[UIApplicationsharedApplication]openURL:[NSURLURLWithString:email]];
8.打电话到一个号码

    // Call Google 411
    [[UIApplicationsharedApplication]openURL:[NSURLURLWithString:@"tel://8004664411"]];

9.发送短信

    // Text to Google SMS
    [[UIApplicationsharedApplication]openURL:[NSURLURLWithString:@"sms://466453"]];

10.打开一个网址

   // Lanuch any iPhone developers fav site
    [[UIApplicationsharedApplication]openURL:[NSURLURLWithString:@"http://itunesconnect.apple.com"]];