ios - 如果应用已打开，则不发送每日本地通知

Question

我每天都在同一时间发送Local Notification。

我想知道是否存在一种方法，如果用户当天已打开应用程序，是否不发送通知？

这是我用来检查是否允许通知然后发送通知的代码:

- (void)viewDidLoad {
 [super viewDidLoad];

 UIUserNotificationType types = UIUserNotificationTypeBadge | UIUserNotificationTypeSound | UIUserNotificationTypeAlert;
 UIUserNotificationSettings *mySettings = [UIUserNotificationSettings settingsForTypes:types categories:nil];
 [[UIApplication sharedApplication] registerUserNotificationSettings:mySettings];

 // before we create any new ones, cancel all existing notifications
 [[UIApplication sharedApplication]cancelAllLocalNotifications];

 if ([[[UIApplication sharedApplication] currentUserNotificationSettings] types] != UIUserNotificationTypeNone) {

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

 NSCalendar *cal = [NSCalendar currentCalendar];
 NSDateComponents *comp = [cal components:(NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute) fromDate:[NSDate date]];
 comp.hour = 19; // 19 = 7PM
 comp.minute = 45; // 7:45 PM
 comp.second = 01; // 7:45:01 PM

 localNotification.fireDate = [cal dateFromComponents:comp];
 localNotification.alertBody = @"Local Notification in iOS8";
 localNotification.timeZone = [NSTimeZone defaultTimeZone];
 localNotification.repeatInterval = NSCalendarUnitDay;

 // this will schedule the notification to fire at the fire date
 [[UIApplication sharedApplication] scheduleLocalNotification:localNotification];
 // this will fire the notification right away, it will still also fire at the date we set
 [[UIApplication sharedApplication] presentLocalNotificationNow:localNotification];

 }
}

编辑:这是我尝试根据以下答案实现方法建议的代码？我显然在这里没有得到什么:/

- (void)isDateLowerThanToday {
    NSDate *now = [NSDate date];
    int daysToAdd = -1;
    NSDate *newDate1 = [now dateByAddingTimeInterval:60*60*24*daysToAdd];
    NSLog(@"NewDate1 = %@", newDate1);
}

Answer 1

您可以在 NSUserDefaults 上存储上次发送通知的日期。然后，当应用打开时，您将检查此值，如果它为null或小于今天，则发送通知并使用当前日期更新NSUserDefaults上的值。

这样的事情应该可以解决问题

NSString *key = @"LAST_NOTIFICATION_SENT_DATE";
NSDate *date = [[NSUserDefaults standardUserDefaults] objectForKey:key];

// You have to implement isDateLowerThanToday
if (!date || [self isDateLowerThanToday:date]) { 
    [self sendNotification];
    date = [NSDate date];
    [[NUserDefaults standardUserDefaults] setObject:date forKey:key];
}

在这里，您有 isDateLowerThanToday实现

-(bool)isDateLowerThanToday:(NSDate *)date {
    NSDate * now = [NSDate date];
    NSComparisonResult result = [now compare:date];

    return result == NSOrderedDescending;
}