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"]];