Question

案例：如果您将时间设置为上午8:00，将天设置为周一和周三，那么我们会在周一和周三上午8:00通知用户。处理这种情况的最佳方法是什么。

到目前为止，我搜索了UILocalNotofication和NSTimer。还有其他需要处理的事情吗？

Answer 1

这个关于如何使用UILocalNotification

进行操作的Apple示例

- (void)scheduleAlarmForDate:(NSDate*)theDate
{
    UIApplication* app = [UIApplication sharedApplication];
    NSArray*    oldNotifications = [app scheduledLocalNotifications];

    // Clear out the old notification before scheduling a new one.
    if ([oldNotifications count] > 0)
        [app cancelAllLocalNotifications];

    // Create a new notification.
    UILocalNotification* alarm = [[UILocalNotification alloc] init];
    if (alarm)
    {
        alarm.fireDate = theDate;
        alarm.timeZone = [NSTimeZone defaultTimeZone];
        alarm.repeatInterval = 0;
        alarm.soundName = @"alarmsound.caf";
        alarm.alertBody = @"Time to wake up!";

        [app scheduleLocalNotification:alarm];
    }
}

Apple不允许你在后台运行NSTimers（存在一些安全问题），这个Apple Guide解释了如何在后台运行任务并有一些代码示例，如上所述。 / p>

Answer 2

我已阅读其他设置闹钟的方法in this blog

否则，我认为你必须使用通知。

NSCalendar *calendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];
NSDate *now = [NSDate date];
NSDateComponents *componentsForFireDate = [calendar components:(NSYearCalendarUnit | NSWeekCalendarUnit|  NSHourCalendarUnit | NSMinuteCalendarUnit| NSSecondCalendarUnit | NSWeekdayCalendarUnit) fromDate: now];
[componentsForFireDate setWeekday: 2] ; 
[componentsForFireDate setHour: 8] ; 
[componentsForFireDate setMinute:0] ;
[componentsForFireDate setSecond:0] ;

NSDate *fireDateOfNotification = [calendar dateFromComponents: componentsForFireDate];
UILocalNotification *notification = [[UILocalNotification alloc]  init] ;
notification.fireDate = fireDateOfNotification ;
notification.timeZone = [NSTimeZone localTimeZone] ;
notification.alertBody = [NSString stringWithFormat: @"Hi!"] ;
notification.userInfo= [NSDictionary dictionaryWithObject:[NSString stringWithFormat:@"Updates added for that week!"] forKey:@"subtitle"];
notification.repeatInterval= NSWeekCalendarUnit ;
notification.soundName=UILocalNotificationDefaultSoundName;


[[UIApplication sharedApplication] scheduleLocalNotification:notification] ;

在特定时间在iOS中触发背景中的方法

2 个答案: