Question

我安排了一个通知，并在它显示警告信息之前给它60分钟警告......

一旦我添加通知，我的App Delegate中的方法就会被调用：

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

我怎么知道它会在后台显示为警告？我是否需要覆盖或使用任何其他委托方法，以确保给定具有60分钟间隔的预定警报......

- (void)scheduleNotificationWithItem:(NSDate *)item interval:(int)minutesBefore
{   
    NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar];

    NSDateComponents *dateComps = [[NSDateComponents alloc] init];
    //NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

    NSDateComponents *currentDateComponents = [calendar components:( NSWeekdayCalendarUnit | 
                                                                     NSYearCalendarUnit | NSMonthCalendarUnit | NSHourCalendarUnit | NSMinuteCalendarUnit | NSWeekCalendarUnit | NSMinuteCalendarUnit) fromDate:item];

    NSLog(@"- current components year = %i , month = %i , week = % i, weekday = %i", [currentDateComponents year], [currentDateComponents month], [currentDateComponents week], [currentDateComponents weekday]);

    NSLog(@"[currentDateComponents minute]: %i",    [currentDateComponents minute]);
    NSLog(@"[currentDateComponents hour]: %i",      [currentDateComponents hour]);
    NSLog(@"[currentDateComponents day]: %i",       [currentDateComponents day]);
    NSLog(@"[currentDateComponents week]: %i",      [currentDateComponents week]);
    NSLog(@"[currentDateComponents month]: %i",     [currentDateComponents month]);
    NSLog(@"[currentDateComponents year]: %i",      [currentDateComponents year]);

    [dateComps setDay: [currentDateComponents day]];

    [dateComps setMonth:[currentDateComponents month]];

    [dateComps setYear:[currentDateComponents year]];

    [dateComps setHour:[currentDateComponents hour]];

    [dateComps setMinute:[currentDateComponents minute]];

    NSDate *itemDate = [calendar dateFromComponents:dateComps];

    [dateComps release];

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

    if (localNotif == nil)
        return;

    localNotif.fireDate = [itemDate addTimeInterval:-(minutesBefore*60)];

    localNotif.timeZone = [NSTimeZone defaultTimeZone];

    localNotif.alertBody = [NSString stringWithFormat:@"%@\n%@",
                            streetAddress,
                            stringOfWhenAuctionIsOn];

    localNotif.alertAction = NSLocalizedString(@"View Details", nil);

    localNotif.soundName = UILocalNotificationDefaultSoundName;

    localNotif.applicationIconBadgeNumber = 1;

    NSDictionary *infoDict = [NSDictionary dictionaryWithObject:streetAddress
                                                         forKey:idOfStreetAlert];

    localNotif.userInfo = infoDict;

    [[UIApplication sharedApplication] scheduleLocalNotification:localNotif];

Answer 1

如果通知立即出现，那么fireDate属性可能有问题。看起来您正在尝试验证发送的日期是否正确，但您还应验证该fireDate是否符合预期。

另外，你也许可以做到

localNotif.fireDate = [item dateByAddingTimeInterval:-60*minutesBefore];

达到同样的效果，不必乱用NSDateComponents。我没有对此进行过测试，但可能会有效。

当计时器触发且您的应用未运行时会发生什么。如果应用尚未终止application:didReceiveLocalNotification:将被调用。如果您的应用已被终止，则需要按照@Ishu的指示检查application:didFinishLaunchingWithOptions:。我通常只是将通知传递给一个常用方法，以避免重复代码。

Answer 2

没有背景的委托方法，你需要在didFinishLaunchingWithOptions中编写代码，

UILocalNotification *localNotif =
    [launchOptions objectForKey:UIApplicationLaunchOptionsLocalNotificationKey];

    if (localNotif) {
        //your code
        NSLog(@"Recieved Notification %@",localNotif);
    }

当应用程序从后台获取通知时，它会创建您的逻辑。不要担心应用程序会收到您设置通知的通知。

UILocalNotification安排警报

2 个答案: