Question

我写了一个应用程序，允许用户在日期选择器上输入日期，然后当他们点击按钮时，它将安排本地通知。唯一的问题是，当我点击按钮时，通知会立即触发。任何帮助深表感谢！这是我的代码：

 - (IBAction)scheduleNotifButton:(id)sender {
        NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];
NSDate *currentDate = [self.datePicker date];

NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
[dateComponents setDay:-3];

NSDate *targetDate = [calendar dateByAddingComponents:dateComponents toDate:currentDate options:0];

        UILocalNotification *localNotif = [[UILocalNotification alloc] init];
        if (localNotif == nil)
            return;
        localNotif.fireDate = targetDate;
        localNotif.timeZone = [NSTimeZone defaultTimeZone];

        localNotif.alertBody = @"Event is in 3 days!";
        localNotif.alertAction = nil;

        localNotif.soundName = UILocalNotificationDefaultSoundName;
        localNotif.applicationIconBadgeNumber = 0;

        [[UIApplication sharedApplication] scheduleLocalNotification:localNotif];

    }

Answer 1

您需要使用[NSCalendar dateByAddingComponents:toDate:options:]代替：

NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];
NSDate *currentDate = [self.datePicker date];

NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
[dateComponents setDay:-3];

NSDate *targetDate = [calendar dateByAddingComponents:dateComponents toDate:currentDate options:0];

[dateComponents release];

...

Answer 2

如果您正在寻找关于如何稍后安排通知的完整代码（比如说3秒），这里是完整的代码：

注意：如果您在应用程序内部，则不会在屏幕顶部看到一个消息框，可能必须通过UIApplication委托处理。

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

NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];
NSDate *currentDate = [[NSDate alloc] init];

NSDateComponents *dateComponents = [[NSDateComponents alloc] init];
[dateComponents setSecond: 3 ];

NSDate *targetDate = [calendar dateByAddingComponents:dateComponents toDate:currentDate options:0];

localNotification.fireDate = targetDate;

localNotification.timeZone = [NSTimeZone defaultTimeZone];

localNotification.alertBody = @"Notified";
localNotification.alertAction = @"Show";
localNotification.soundName = UILocalNotificationDefaultSoundName;
localNotification.applicationIconBadgeNumber = 1;

[[UIApplication sharedApplication] scheduleLocalNotification:localNotification];

iOS：3天前的简单本地通知

2 个答案: