iOS/Obj-C - 在没有计时器的情况下触发本地通知？

Question

我想在我的 iOS 应用程序中设置一些本地通知，但是我似乎找到的关于实现这些的每个教程似乎只允许我基于计时器触发通知（参见下面的示例代码）？例如，当新数据加载到 UITableView 时，是否可以触发本地通知？对于一般性问题，我很抱歉，但我似乎找不到很多关于此的文档。我也不确定如果仅在用户点击屏幕时才获取数据，我该怎么做？ 例如数据在 ViewController 的 viewDidLoad 中被抓取/更新？

-(void)viewDidLoad {

        UILocalNotification *localNotification = [[UILocalNotification alloc] init];
        localNotification.fireDate = dateTime;
        localNotification.alertBody = [NSString stringWithFormat:@"Alert Fired at %@", dateTime];
        localNotification.soundName = UILocalNotificationDefaultSoundName;
        localNotification.applicationIconBadgeNumber = 1;
        [[UIApplication sharedApplication] scheduleLocalNotification:localNotification];

    }

Answer 1

首先，您应该考虑一个事实，即您使用的 UILocalNotification 类从 iOS 10 开始已被弃用。从 iOS 10 开始，本地通知和远程通知之间没有区别。

在UserNotifications 框架（iOS 10.0+，Swift | Objective-C）中，不会像 Apple 之前的一些类似框架/API 的实现那样创建UNNotification 的实例。相反，UNNotificationCenter 的实例负责创建通知对象并在收到新通知时和在显示默认 UI 之前调用委托方法。有关符合UNUserNotificationCenterDelegate 协议要求的更多详细信息，请参阅Apple's documentation。 我经常最终使用AppDelegate 作为符合该协议的类

现在回到问题。要从应用程序内开始创建通知，首先您应该创建一个触发器（在您的情况下，您可能希望使用UNTime​Interval​Notification​Trigger），然后创建一个通知请求，最后将该请求添加到可以访问的通知中心单例致电UNUserNotificationCenter.current()。

let content = UNMutableNotificationContent()
content.title = "Alert Fired"

创建一个触发器，用于确定 UNUserNotificationCenter 何时调用通知

let trigger = UNTime​Interval​Notification​Trigger(timeInterval: 0, repeats: false)

创建通知请求。你只创建那些来调用本地通知，因为 iOS 负责为传入的推送通知创建请求对象。

let request = UNNotificationRequest(identifier: "FiveSecond", content: content, trigger: trigger)

现在我们必须将我们的请求添加到与我们的应用关联的当前通知中心。

let center = UNUserNotificationCenter.current()
center.add(request, withCompletionHandler: nil)

在我们的例子中，通知将由 UNUserNotificationCenter 立即触发。

Answer 2

您可以像这样使用 postNotificationName 方法：

MyCustomObject *customObject = [MyCustomObject new];
[[NSNotificationCenter defaultCenter] postNotificationName:@"Your notification name" object:customObject];

处理来自已发布通知的对象看起来像这样。显然，我只是在这里登录，但你可以随意处理它。

- (void)methodToProcessNotificationData:(NSNotification *)notification {
   NSLog(@"%@",notification.object);
}

当你想要一个类来监听通知时，你可以执行下面的代码块。这会将观察者添加到类中，为其提供要调用的方法（在此实例中为 methodToProcessNotificationData）以及您希望监听的通知名称。

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(methodToProcessNotificationData:) name:@"Your notification name" object:nil];

Answer 3

您可以改用以下方法[1]：

- (void)postNotificationName:(NSNotificationName)aName 
                      object:(id)anObject 
                    userInfo:(NSDictionary *)aUserInfo;

[1]https://developer.apple.com/reference/foundation/nsnotificationcenter/1410608-postnotificationname?language=objc

Answer 4

只要您想触发本地通知，您就可以简单地将时间设置为[NSDate date]。它将在当前时间触发通知。

Answer 5

首先要记住你需要什么 ios 本地本地通知

// Handle launching from a notification

if(IOS_VERSION<10)
{
    UILocalNotification *locationNotification = [launchOptions objectForKey:UIApplicationLaunchOptionsLocalNotificationKey];
    if (locationNotification)
 {
    // Set icon badge number to zero
    application.applicationIconBadgeNumber = 0;
}

if ([UIApplication instancesRespondToSelector:@selector(registerUserNotificationSettings:)])
{

    [application registerUserNotificationSettings:[UIUserNotificationSettings
                                                   settingsForTypes:UIUserNotificationTypeAlert|UIUserNotificationTypeBadge|
                                                   UIUserNotificationTypeSound categories:nil]];
}

}其他{

[[UNUserNotificationCenter currentNotificationCenter] requestAuthorizationWithOptions:(UNAuthorizationOptionAlert + UNAuthorizationOptionSound)
                                                                    completionHandler:^(BOOL granted, NSError * _Nullable error) {
                                                                        // Enable or disable features based on authorization.
                                                                    }];

}

最后一件事

    if(IOS_VERSION<10){

        [[UIApplication sharedApplication] cancelAllLocalNotifications];

        NSLog(@"LocalNotifications]count %d",(int) [[[UIApplication sharedApplication] scheduledLocalNotifications]count]);

        NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar] ;
        NSDate *now = [NSDate date];
        NSDateComponents *components = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth |  NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute) fromDate:now];
        [components setHour:15];
        [components setMinute:35];

        UILocalNotification *notification = [[UILocalNotification alloc]init];
        notification.fireDate = [calendar dateFromComponents:components];
        notification.repeatInterval = NSCalendarUnitDay;
        notification.alertBody =@"message";
        notification.applicationIconBadgeNumber = 0;
        notification.soundName = UILocalNotificationDefaultSoundName;
        [[UIApplication sharedApplication] scheduleLocalNotification:notification];


    }else{

        [[UNUserNotificationCenter currentNotificationCenter] removeAllPendingNotificationRequests];
        NSLog(@"LocalNotifications]count %d",(int) [[[UIApplication sharedApplication] scheduledLocalNotifications]count]);

        NSCalendar *calendar = [NSCalendar autoupdatingCurrentCalendar] ;
        NSDate *now = [NSDate date];
        NSDateComponents *components = [calendar components:(NSCalendarUnitYear | NSCalendarUnitMonth |  NSCalendarUnitDay | NSCalendarUnitHour | NSCalendarUnitMinute) fromDate:now];
        [components setHour:15];
        [components setMinute:35];




        UNMutableNotificationContent *objNotificationContent = [[UNMutableNotificationContent alloc] init];
//        objNotificationContent.title = [NSString localizedUserNotificationStringForKey:NotificationHeading arguments:nil];
        objNotificationContent.body = [NSString localizedUserNotificationStringForKey:@"message"
                                                                            arguments:nil];
        objNotificationContent.sound = [UNNotificationSound defaultSound];

        /// 4. update application icon badge number
        objNotificationContent.badge = @([[UIApplication sharedApplication] applicationIconBadgeNumber]);

//        UNTimeIntervalNotificationTrigger* trigger = [UNTimeIntervalNotificationTrigger
//                                                      triggerWithTimeInterval:60 repeats:YES];

        UNCalendarNotificationTrigger *trigger2 = [UNCalendarNotificationTrigger triggerWithDateMatchingComponents:components repeats:YES];

        UNNotificationRequest* request = [UNNotificationRequest requestWithIdentifier:@"FiveSecond"
                                                                              content:objNotificationContent trigger:trigger2];

        /// 3. schedule localNotification
        UNUserNotificationCenter *center = [UNUserNotificationCenter currentNotificationCenter];


        [center addNotificationRequest:request withCompletionHandler:^(NSError * _Nullable error) {
            if (!error) {
                NSLog(@"Local Notification succeeded");
            }
            else {
                NSLog(@"Local Notification failed");
            }
        }];


    }