I want to upload images when home button pressed and application goes in background.
Is it possible? If yes then how? and if no then do i have any other alternative?
Thanks in advance...
You can perform a task in background by using this code for a specific time-
UIBackgroundTaskIdentifier bgTask = 0;
UIApplication *app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
}];
self.silenceTimer = [NSTimer scheduledTimerWithTimeInterval:10 target:self
selector:#selector(startLocationServices) userInfo:nil repeats:YES];
Refer this:
http://developer.apple.com/library/ios/#documentation/iphone/conceptual/iphoneosprogrammingguide/ManagingYourApplicationsFlow/ManagingYourApplicationsFlow.html
I think this will help u. :)
An app can request to run in the background for up to 10 minutes after it has been closed so that it can finish a long-running task. Only some processes are allowed to run in background. See Implementing Long-Running Background Tasks section in this reference.
If your app is allowed so, you can try below code:
- (void)applicationDidEnterBackground:(UIApplication *)application
{
UIBackgroundTaskIdentifier bgTask;
bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
// Clean up any unfinished task business by marking where you
// stopped or ending the task outright.
[application endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task, preferably in chunks.
[application endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
});
}
if you want to know how much time your app has left to run
NSTimeInterval ti = [[UIApplication sharedApplication]backgroundTimeRemaining];
NSLog(#"Remaining Time: %f", ti); // just for debug
For more ref go with this reference PDF(page 60)
Related
I am using beginBackgroundTaskWithExpirationHandler to get 10 minutes extra time for the application to run in background. But I need to stop this background task if the application comes foreground within the provided 10 minutes of time. My code is as follows
- (void)applicationDidEnterBackground:(UIApplication *)application
{
bgTask = [application beginBackgroundTaskWithExpirationHandler: ^ {
NSLog(#"invalidate back task in didenter %#",[application backgroundTimeRemaining]);
if (bgTask != UIBackgroundTaskInvalid) {
[application endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
}];
//Background tasks require you to use asyncrous tasks
dispatch_async(dispatch_get_main_queue(), ^{
NSLog(#"\n\nRunning in the background inside DidEnterBackground %f!\n\n", [application backgroundTimeRemaining]);
while ([application backgroundTimeRemaining] > 1.0) {
NSLog(#"\n\nRunning in background %f!\n\n", [application backgroundTimeRemaining]);
sleep(5);
}
[application endBackgroundTask: bgTask];
bgTask = UIBackgroundTaskInvalid;
});
}
And when app comes foreground I am ending background task like this
- (void)applicationWillEnterForeground:(UIApplication *)application
{
[application endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
bgTask is declared globally in .h file. When app goes foreground its still running the background task with showing backgroundTimeRemaining as a long integer value. I am not getting how to stop the background task please help me.
Thanks
I am uploading some pictures to server in background. I want to close app after 10 mins. But my app is not closing, it is in pause mode in background and when I press app icon upload operation again starts in foreground. I used below code:
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
// Clean up any unfinished task business by marking where you.
// stopped or ending the task outright.
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Here goes your operation
// done!
upload_photo();
dispatch_async(dispatch_get_main_queue(), ^{
if (bgTask != UIBackgroundTaskInvalid)
{
// if you don't call endBackgroundTask, the OS will exit your app.
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
});
});
My Question: How can I close my app after 10 min.(upload task complete or not)?
Thanks in advance.
In our app, we need to de-reg a user when he pushes the app to the background.
We are using PJSIP. My applicationDidEnterBackground:
- (void)applicationDidEnterBackground:(UIApplication *)application {
NSLog(#"did enter background");
__block UIBackgroundTaskIdentifier bgTask;
bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
[application endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self deregis];
[application endBackgroundTask: bgTask]; //End the task so the system knows that you are done with what you need to perform
bgTask = UIBackgroundTaskInvalid; //Invalidate the background_task
NSLog(#"\n\nRunning in the background!\n\n");
});
}
The deregis method is as below:
- (void)deregis {
if (!pj_thread_is_registered())
{
pj_thread_register("ipjsua", a_thread_desc, &a_thread);
}
dereg();
}
And the de-reg method is as below:
void dereg()
{
int i;
for (i=0; i<(int)pjsua_acc_get_count(); ++i) {
if (!pjsua_acc_is_valid(i))
pjsua_buddy_del(i);
pjsua_acc_set_registration(i, PJ_FALSE);
}
}
When we push the app to the background, the dereg gets called. But when the server sends back a 401 challenge, the stack isn't sending back the auth details in SIP call until I bring the application back to foreground.
Does anyone have any idea why this is happening?
Thanks,
Hetal
You don't want to end the background task in your background thread:
e.g.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self deregis];
// don't do below...
// [application endBackgroundTask: bgTask]; //End the task so the system knows that you are done with what you need to perform
// bgTask = UIBackgroundTaskInvalid; //Invalidate the background_task
NSLog(#"\n\nRunning in the background!\n\n");
});
You want to end the background task when the registration is updated. So you need to hook into the pjsua on_reg_state callback.
e.g. this example may only assume one unregister, for multiple accounts you have to wait until all are unregistered
-(void) regStateChanged: (bool)unregistered {
if (unregistered && bgTask != UIBackgroundTaskInvalid) {
[application endBackgroundTask: bgTask]; //End the task so the system knows that you are done with what you need to perform
bgTask = UIBackgroundTaskInvalid; //Invalidate the background_task
}
}
I am doing SMTP related app in my application, to send the mail.In IOS 4 background execution exceptions for audio,voip,location.How to use network operation.
There is no explicit exception for network access. You can request extra time to complete a task after your app exits but you can't create a daemon process that continually runs in the background.
Apple provides 600 sec to execute background task you can take help with code
UIApplication *app = [UIApplication sharedApplication];
self.bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
// Start the long-running task
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
while (1) {
NSLog(#"BGTime left: %f", [UIApplication sharedApplication].backgroundTimeRemaining);
[self.viewController performSelector:#selector(invokeCuisineSelector)];
sleep(1);
}
});
Actually I am working for multitasking and facing error please assist me, as I need to work on background application and also in foreground application
- (void)applicationDidEnterBackground:(UIApplication *)application
{
UIApplication* app = [UIApplication sharedApplication];
// Request permission to run in the background. Provide an
// expiration handler in case the task runs long.
NSAssert(bgTask == UIBackgroundTaskInvalid, nil);
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
// Synchronize the cleanup call on the main thread in case
// the task actually finishes at around the same time.
dispatch_async(dispatch_get_main_queue(), ^{
if (bgTask != UIBackgroundTaskInvalid)
{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
});
}];
// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task.
// Synchronize the cleanup call on the main thread in case
// the expiration handler is fired at the same time.
dispatch_async(dispatch_get_main_queue(), ^{
if (bgTask != UIBackgroundTaskInvalid)
{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
});
});
}
Put in your #interface:
UIBackgroundTaskIdentifier bgTask;
(out from NDA now).
Check out the developer documentation, if you have a developer's account. We can't really answer the os4.0 question because it's under NDA, but all the information you'll need to answer that question is on that page (once logged in).