iOS UIBackgroundMode remote-notification doesn't work on 4G

Question

I'm testing push notifications with content-available=1, and they don't seem to be delivered to the app in the background unless on Wi-Fi.

I have a simple log statement at the beginning of the push notification handler:

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
                                                    fetchCompletionHandler:(void (^)   (UIBackgroundFetchResult))completionHandler {

    NSLog(@"Notification received: %@", userInfo);
    completionHandler(UIBackgroundFetchResultNewData);
}

Here is my test:

1. Run the app, then press the home button to put the app in the background.
2. Send a push notification with content-available=1
3. Watch console logs

On Wi-Fi, the console log shows the notification. If I go to Settings and turn off Wi-Fi, switching to 4G, notifications no longer appear in the log (although they do slide in at the top of the screen, so I know they are being delivered).

There are no crash logs, and the notification is logged if I manually tap on it. Furthermore, this problem does NOT occur if I am debugging the app in Xcode. (i.e., if I am debugging in Xcode, the app will receive the notification in the background on 4G). Has anyone else experienced this behavior? Or am I doing something wrong?

EDIT: To be specific: according to my tests, if the following conditions are true, then the remote notification delegate method above will not be called:

1. App is running in the background
2. Phone is on LTE network, not connected to Wi-Fi
3. App is NOT running in the Xcode debugger
4. Notification with content-available=1 is received by the phone

However if condition 2 is removed (i.e., the phone is connected to Wi-Fi), then the handler will be called.

Answer 1

Try the following code:

// AppDelegate.h

@class ViewController;

@interface AppDelegate : UIResponder <UIApplicationDelegate>
{

    NSString *DeviceToken;
    NSMutableDictionary *App_Messages;

    NSString *Longitude,*Latitude;
    NSMutableDictionary * badge;
}

@property (strong, nonatomic) UIWindow *window;

@property (strong, nonatomic) ViewController *viewcontrollervc;

@property (strong, nonatomic) UINavigationController *navcontroller;

@property (nonatomic,retain)NSMutableDictionary *badge;

@property (nonatomic,retain)NSString *DeviceToken;

　 　

// AppDelegate.m

#import "ViewController.h"

@implementation AppDelegate

@synthesize badge,DeviceToken;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

    self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]];
    self.viewcontrollervc = [[ViewController alloc]initWithNibName:@"ViewController" bundle:nil];
    self.navcontroller = [[UINavigationController alloc]initWithRootViewController:self.viewcontrollervc];
    self.window.rootViewController = self.navcontroller;
    self.navcontroller.navigationBarHidden = YES;


    //Notification
    [[UIApplication sharedApplication] registerForRemoteNotificationTypes:
     (UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeSound | UIRemoteNotificationTypeAlert)];
    NSDictionary * remoteNotificationObj = [launchOptions objectForKey:@"UIApplicationLaunchOptionsRemoteNotificationKey"];
    if (remoteNotificationObj)
    {
        [self performSelector:@selector(handleRemoteNotificationWithUserInfo:) withObject:remoteNotificationObj afterDelay:3.0];
    }

    [self.window makeKeyAndVisible];
    return YES;

}


- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo
{

    [self handleRemoteNotificationWithUserInfo:userInfo];

}

-(void)handleRemoteNotificationWithUserInfo:(NSDictionary *)userInfo
{

    NSLog(@"userInfo - %@",userInfo);
    NSDictionary *alertData = [userInfo objectForKey:@"aps"];
    NSDictionary *returnDatalert=[alertData objectForKey:@"alert"];
    NSString *alertmsg=[returnDatalert objectForKey:@"body"];

    NSLog(@"alertmsg %@",alertmsg);
    self.badge = [NSMutableDictionary dictionaryWithDictionary:[alertData objectForKey:@"badge"]];
    NSString *notificationtype=[badge objectForKey:@"fnct"];

    NSLog(@"%@",notificationtype);

}


- (void)application:(UIApplication *)application didRegisterForRemoteNotificationsWithDeviceToken:(NSData *)deviceToken
{

   NSLog(@"didRegisterForRemoteNotificationsWithDeviceToken: %@", deviceToken);
    NSString *dt = [[deviceToken description] stringByTrimmingCharactersInSet:[NSCharacterSet characterSetWithCharactersInString:@"<>"]];
    dt = [dt stringByReplacingOccurrencesOfString:@" " withString:@""];
    self.DeviceToken=dt;
    NSLog(@"~~~~devToken(dv)=%@",deviceToken);

}

- (void)application:(UIApplication*)application didFailToRegisterForRemoteNotificationsWithError:(NSError*)error
{

    NSLog(@"Failed to get token, error: %@", error);

}