Ios 本地通知未到达

我正在运行背景代码，以检查网站是否有任何更改，如果有更改，则发送本地通知以提醒用户。但是，当我运行代码并尝试它时，本地通知不会到达。 这是我的appDelegate.m中的代码

- (void)applicationDidEnterBackground:(UIApplication *)application {
    NSLog(@"Has Entered Background");
    timerCountDown = [NSTimer scheduledTimerWithTimeInterval:60.0 target:self selector:@selector(backGroundParsing) userInfo:nil repeats:YES];
}

- (void)backGroundParsing {
    //This is where my background checking happens. I deleted the code here to make it shorter.
    if (totalNumberOfEvents > totalNumberOfEvetsRecorded) {
                                NSLog(@"Notificatoin sent");
                                NSString *finalNumberOfEventsRecorded = [NSString stringWithFormat:@"%d",totalNumberOfEvents];
                                NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
                                [userDefaults setObject:finalNumberOfEventsRecorded forKey:@"finalRegisteredNumberOfEvents"];
                                UILocalNotification *notifyUserAboutNewEvent = [[UILocalNotification alloc] init];
                                [notifyUserAboutNewEvent setFireDate:[NSDate dateWithTimeIntervalSinceNow:1]];
                                [notifyUserAboutNewEvent setTimeZone:[NSTimeZone defaultTimeZone]];
                                [notifyUserAboutNewEvent setAlertBody:@"New event has been organised"];
                                [[UIApplication sharedApplication] setScheduledLocalNotifications:[NSArray arrayWithObject:notifyUserAboutNewEvent]];
                            }
}

我确实记录了“已发送通知”，但没有收到任何通知。有什么遗漏或错误吗？我的其他无效操作中没有任何其他代码

编辑 在@rckoenes说了些什么之后，我将我的代码编辑成这样

- (void)application:(UIApplication * _Nonnull)application
performFetchWithCompletionHandler:(void (^ _Nonnull)(UIBackgroundFetchResult result))completionHandler {
    [self backGroundParsing];
}

- (void)backGroundParsing {
    //This is where my background checking happens. I deleted the code here to make it shorter.
                            if (totalNumberOfEvents > totalNumberOfEvetsRecorded) {
                                NSLog(@"Notificatoin sent");
                                NSString *finalNumberOfEventsRecorded = [NSString stringWithFormat:@"%d",totalNumberOfEvents];
                                NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
                                [userDefaults setObject:finalNumberOfEventsRecorded forKey:@"finalRegisteredNumberOfEvents"];
                                UILocalNotification *notifyUserAboutNewEvent = [[UILocalNotification alloc] init];
                                [notifyUserAboutNewEvent setFireDate:[NSDate dateWithTimeIntervalSinceNow:1]];
                                [notifyUserAboutNewEvent setTimeZone:[NSTimeZone defaultTimeZone]];
                                [notifyUserAboutNewEvent setAlertBody:@"New event has been organised"];
                                [[UIApplication sharedApplication] setScheduledLocalNotifications:[NSArray arrayWithObject:notifyUserAboutNewEvent]];
                            }
                        });
     }];
    [searchEventsTask resume];
}

但是，我仍然没有收到通知。我在模拟背景提取时收到警告。这是出现在我的NSLog中的警告

警告：应用程序代理收到了对-Application:performFetchWithCompletionHandler:的调用，但从未调用过完成处理程序。

---

模拟后台提取时，此警告正常吗？我的通知仍然没有出现。如何修复它？

在iOS 8+中，您必须获得用户的本地通知权限。在您的

应用程序didFinishLaunchingWithOptions

方法中添加以下行：

[[UIApplication sharedApplication] registerUserNotificationSettings:[UIUserNotificationSettings settingsForTypes:UIUserNotificationTypeAlert|UIUserNotificationTypeBadge| UIUserNotificationTypeSound categories:nil]];

---

您不能在后台使用计时器。当应用程序进入后台时，您设置了

UILocalNotification

，并使用

fireDate

将通知延迟60秒。但是如果我不使用计时器，它只会检查更改一次，只需从

applicationidenterbackground:

调用

backGroundParsing

，它应该可以工作。但是它不会只叫一次吗？你说只叫一次是什么意思？