I am calling webservice in foregroud while the downloading is in progress, I press home button (app is in background now), I want to continue the fetching/downloading in background and complete it, is this possible in iOS? if yes then how can i achieve this?
Thanks in advance.
Please use URLSessionDownloadTask for downloading any data in the background and enable Background fetch under the background modes in capabilities.
For more info please refer,
Downloading files in background
Added below code in applicationDidEnterBackground appdelegate method and it works for me.
UIApplication *app = [UIApplication sharedApplication];
UIBackgroundTaskIdentifier bgTask;
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
}];
Related
How can we pragmatically remove any pending remote notifications sent for my app from notification centre. I want to clear them up on app launch.
I have tried with [[UIApplication sharedApplication] cancelAllLocalNotifications]; API but its not helping.
PS: This question is specific to iOS 10 and old threads are not duplicates for this one.
Finally...
This one works like charm!
[[UNUserNotificationCenter currentNotificationCenter] removeAllDeliveredNotifications];
You can clear all notifications from notification centre by using these simple lines of code
[[UIApplication sharedApplication] setApplicationIconBadgeNumber: 1];
[[UIApplication sharedApplication] setApplicationIconBadgeNumber: 0];
[[UIApplication sharedApplication] cancelAllLocalNotifications];
use wherever you want. From my side I have used when user pressed logout.
You can use in
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
method to clear notifications after app opens
AFAIK, you should do it by using the background mode for remote notifications, and then responding to these notifications by issuing a local notifications.
You can remove local notifications, but not remote notifications.
Reseting the application badge number also remove all the notifications (local & remote) from the notification center.
Objective C
[UIApplication sharedApplication].applicationIconBadgeNumber = 0;
Swift
UIApplication.shared.applicationIconBadgeNumber = 0
This can definitely be achieved by using removeDeliveredNotifications(withIdentifiers:) method available in UserNotifications.framework.
For a detailed tutorial, please follow this
https://medium.com/#sebastianosiski/implementing-removable-remote-notifications-on-ios-a17d74832bde
I am developing an application for a custom wearable communicating through BLE.
I have subscribed to the UI background modes in the info.plist file for Bluetooth-central.
I am transferring a firmware file of around 600 kb by dividing into chunk sizes of 200 bytes each. The process is going fine but as I am pressing the Home button the app is entering into background state and thus terminating the process after 1-2 minutes.
If my screens dims after certain amount of time then the firmware transfer continues but as soon as the home button is pressed the app stops transferring the data after few minutes.
Please help me out of this scenario.
Thanks.
To run task in background mode, you need to follow the belowed steps.
Step 1: Declare __block UIBackgroundTaskIdentifier bgTask as global variable.
Step 2: To add following code in applicationDidEnterBackground.
- (void)applicationDidEnterBackground:(UIApplication *)application {
bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
bgTask = UIBackgroundTaskInvalid;
}];
}
Step 3: Stop background task handler once apps come in foreground mode.
- (void)applicationWillEnterForeground:(UIApplication *)application {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
}
i am working on one tracking application in that i use location manager service and
set desiredAccuracy = kCLLocationAccuracyNearestTenMeters
and distanceFilter = 60.0.
i want to give background support. for that i
set App registers for location updates,
App downloads content from the network
in my info.plist. and i put
[[UIApplication sharedApplication] setMinimumBackgroundFetchInterval:UIApplicationBackgroundFetchIntervalMinimum];
this code in didFinishLaunchingWithOptions method.
i also use this method for call startUpdatingLocation location manager method
- (void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler
this all work in iOS 7 with iPhone4
but i have other two device in iPhone4S and iPhone5 in that device when device is ideal at that time application is in background so the navigation symbol get disappear and my location data not get updated on server.
when phone is ideal and when i start my application its not in background my application start from login screen.
so background location update not work for iPhone5 and iPhone4S having iOS7.
Please provide me solution for this.
my application is for tracking purpose if i am not get updated location so it is useless.
you can add this methods in your AppDelegate.m
- (void)applicationDidEnterBackground:(UIApplication *)application
{
bgTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
NSLog(#"ending background task");
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
timer = [NSTimer scheduledTimerWithTimeInterval:5
target:locationManager
selector:#selector(startUpdatingLocation)
userInfo:nil
repeats:YES
];
}
you can take help with below link:
Start Location Manager in iOS 7 from background task
to get your location update at interval of every 5 minutes.
I am working on one application in which it requires to merge more than one videos. I am using AVExportSession to export merged video. I am also displaying progress bar for exporting video. It is running correctly most of times.
The issue occurs when we lock the screen or put application in background mode. This time if exporting is in process, it immediately fails after putting application in background mode. I have also tried to use background task. Check below code.
bgTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
// Clean up any unfinished task business by marking where you.
// stopped or ending the task outright.
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
But this does not seem to work. What am I doing wrong? Any help would be appreciated.
Sadly, since AVAssetExportSession uses the gpu to do some of it's work, it cannot run in the background if you are using an AVVideoComposition.
I am building a cinema listing app, where the user can drill down thru the dataset to finally end up with a listing for a specific movie/theater/etc.
Now assume the user pauses using the app for 7 days. When reopening the app what he should not see are the listings from 7 days ago. But if the user just puts the app in background for a few minutes, the user should continue just where he left. I thought I could solve this issue by killing the app after a certain amount of time in background. This is the code:
static BOOL goingToQuit = NO;
#define KILL_IN_BACKGROUND_AFTER_SECS 300
- (void)applicationDidEnterBackground:(UIApplication *)application
{
goingToQuit = YES;
UIApplication* app = [UIApplication sharedApplication];
UIBackgroundTaskIdentifier __block bgTask;
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
if(UIBackgroundTaskInvalid != bgTask) {
// Start the long-running task to kill app after some secs and return immediately.
dispatch_after( dispatch_time(DISPATCH_TIME_NOW, KILL_IN_BACKGROUND_AFTER_SECS * 1e09),
dispatch_get_main_queue(), ^{
if(goingToQuit) exit(0);
[app endBackgroundTask: bgTask];
});
}
}
- (void)applicationWillEnterForeground:(UIApplication *)application
{
// cancel ongoing background suicide.
goingToQuit = NO;
}
What I see on my device is this: after KILL_IN_BACKGROUND_AFTER_SECS the app gets killed. After restarting the device logs show that the app got a new PID, entries showing the restart etc. Yet the device does not show the default.png startup image, but the screenshot of where the user has been before.
On the other hand if the user kills the application explicitely (double click on home button, tap & hold, click - on app) before he is restarting it the application starts with its default.png start up screen. This is the behaviour I want when killing the app programmatically.
Does anyone have an idea how to accomplish this? Any idea is highly appreciated.
BTW: As a workaround I tried to hide the main window during applicationDidEnterBackground and show it again on applicationWillEnterForeground. This, however, is highly confusing to the user when he is switching between apps.
In your app delegate's applicationDidEnterBackground you can display a view in front of the rest of your views, which the OS will grab as the last visible thing and which will be displayed when the app becomes active again (if it's still alive).
In your app delegate's applicationDidBecomeActive you can check to see if the data needs updating; if not then simply dismiss the view (animation is nice), and if so then first update (or just clear out) your data and then dismiss the view.
This is fairly common in apps. Many just use the default.png startup image, since users are accustomed to seeing it when the app launches normally.