//需要在AppDelegate里面启动APP的函数 加上

UIUserNotificationType types = UIUserNotificationTypeBadge | UIUserNotificationTypeSound | UIUserNotificationTypeAlert;

    UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:types categories:nil];

    [[UIApplication sharedApplication] registerUserNotificationSettings:settings];

  [[UIApplication sharedApplication] setApplicationIconBadgeNumber:0];

 UNUserNotificationCenter* userNofit=[UNUserNotificationCenter currentNotificationCenter];

    UNMutableNotificationContent* content = [[UNMutableNotificationContent alloc] init];

    content.body =@"body";

    content.sound=[UNNotificationSound defaultSound];//声音

    // 在 alertTime 后推送本地推送  延迟5秒

    UNTimeIntervalNotificationTrigger* trigger = [UNTimeIntervalNotificationTrigger

                                                  triggerWithTimeInterval:5  repeats:NO];

    UNNotificationRequest* request = [UNNotificationRequest requestWithIdentifier:@"L_UN"

                                                                          content:content trigger:trigger];

    [userNofit addNotificationRequest:request withCompletionHandler:^(NSError * _Nullable error) {

        //错误信息处理

    }];