闹钟主要实现代码

UILocalNotification *notification=[[UILocalNotification alloc] init];

    if (notification!=nil) 

    {   

        notification.repeatInterval=NSDayCalendarUnit;

        NSDate *now1=[NSDate new];

        notification.fireDate=[now1 dateByAddingTimeInterval:hm];

        notification.timeZone=[NSTimeZone defaultTimeZone];

        notification.soundName = @"ping.caf";

        notification.alertBody = [NSString stringWithFormat:NSLocalizedString(@"你设置的时间是：%i ： %i .",nil),htime1,mtime1];

       [[UIApplication sharedApplication]   scheduleLocalNotification:notification];

        }

这个是建立后台消息对象

如果是程序开这的可以用UIApplication的代理方法

- (void)application:(UIApplication *)application didReceiveLocalNotification:(UILocalNotification *)notification{

来实现闹钟的响铃