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如果用户当天尚未打开应用程序，我目前正在安排本地通知在每天下午 6 点出现一次。如果用户已经加载了应用程序，那么我想取消当天的通知并在明天下午 6 点安排一个新的通知。通知正确显示，但是，当我尝试迭代计划通知列表时（这不是我在应用程序中拥有的唯一本地通知），[[UIApplication sharedApplication] scheduledLocalNotifications] 数组始终为空。下面是给我带来麻烦的代码片段：

// See if we need to create a local notification to tell the user that they can receive a daily reward
NSArray *notifications = [[UIApplication sharedApplication] scheduledLocalNotifications]; // <- This is always empty
// Iterate over all the pending notifications
for( int iter = 0; iter < [notifications count]; iter++ )
{
    UILocalNotification* localNotification = [notifications objectAtIndex:iter];

    if( [[localNotification.userInfo objectForKey:@"source"] isEqualToString:@"dailyReminder"] )
        [[UIApplication sharedApplication] cancelLocalNotification:localNotification];
}

NSCalendar* calendar = [[[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar] autorelease];
[calendar setTimeZone:[NSTimeZone localTimeZone]];
NSDateComponents *nowComponents = [calendar components:NSDayCalendarUnit | NSMonthCalendarUnit | NSYearCalendarUnit | NSSecondCalendarUnit | NSMinuteCalendarUnit | NSSecondCalendarUnit fromDate:serverDate];

int hour = [nowComponents hour];
int minute = [nowComponents minute];
int second = [nowComponents second];

int hoursToAdd = 18 - hour;

NSDateComponents *comps = [[[NSDateComponents alloc] init] autorelease];
[comps setDay:1];
[comps setHour:hoursToAdd];
[comps setMinute:-minute];
[comps setSecond:-second];
NSDate *tomorrow6PM = [calendar dateByAddingComponents:comps 
                                                toDate:serverDate
                                               options:0];

NSMutableDictionary* userInfo = [NSMutableDictionary dictionary];
[userInfo setObject:@"dailyReminder" forKey:@"source"];

scheduleNotification(tomorrow6PM, NSLocalizedString(@"Come Back!", @"daily reminder notification message"), NSLocalizedString(@"Launch", @"daily reminder notification button text"), [UIApplication sharedApplication].applicationIconBadgeNumber+1, userInfo);

scheduleNotification 函数很简单，只构造一个本地通知：

void scheduleNotification(NSDate* fireIn, NSString* bodyText, NSString* alertText, NSUInteger badgeCount, NSMutableDictionary* userInfo)
{
static int appCount = 0;
appCount += 1;

if(!isLocalNotificationEnabled()) 
    return;

Class localNotificationClass = NSClassFromString(@"UILocalNotification");
UILocalNotification* localNotification = [[localNotificationClass alloc] init];
if(!localNotification)
    return;

localNotification.fireDate = fireIn;
localNotification.timeZone = [NSTimeZone systemTimeZone];
localNotification.alertBody = bodyText;
localNotification.alertAction = alertText;
localNotification.soundName = UILocalNotificationDefaultSoundName;
localNotification.applicationIconBadgeNumber = badgeCount;
localNotification.userInfo = userInfo;

[[UIApplication sharedApplication] scheduleLocalNotification:localNotification];
[localNotification release];
}

我不明白为什么本地通知数组总是空的。就像我在通知显示在正确时间之前所说的那样，因此它们正在被安排。任何帮助表示赞赏。

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3 回答 3

7

现在有类似的问题。我的猜测是 iOS 不会立即安排通知，而只会在当前运行循环结束时安排通知。在同一个运行循环中多次设置 scheduleLocalNotifications 属性时，我遇到了这些问题，并且更改似乎没有相应地更新。我想我自己会保留一份本地通知数组的副本，只设置 scheduleLocalNotifications 而从不阅读它。

于 2012-07-10T18:33:42.917 回答
1 
localNotification.fireDate = fireIn;

在这一行中检查是否“fireIn”是NSDateor的对象NSString。

如果它在帮助下NSString将其转换为NSDate对象，NSDateformatter然后将其分配给localNotificationfireDate。

我以前遇到过同样的问题，并通过上述步骤解决了它。

于 2012-12-20T12:27:48.897 回答
0

如果计划有无效的触发日期，它将不会被计划并返回空数组，因为从来没有一个有效的计划，尝试像下面这样打印出你的 localNotification，你可能会发现问题。

NSLog(@"Notification--->: %@", localNotification);
于 2012-01-04T01:17:52.837 回答