iOS: Run part of code in background

Question

Possible Duplicate:
iOS Background downloads when the app is not active

I'd like my part of code of iOS app continue running when app did enter background.

I have some class that should run sequence of functions. Every function load data async using ASIHTTPRequest. I want to keep running these functions when app is in background and when the last ASIHTTP request complete I should to show the local notification.

I have something like follow code

- (void) start //call this method from another class
{
    __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
    [request setShouldContinueWhenAppEntersBackground:YES];
    [request setCompletionBlock:^{
        NSData *responseData = [request responseData];

        NSXMLParser *xmlParser = [[NSXMLParser alloc] initWithData:responseData];
        [xmlParser setDelegate:self];
        [xmlParser parse];
        [xmlParser release];
    }];
    [request startAsynchronous];
}

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    //parse xml
    if(all is Ok)
    {
        [self func1];
    }
}

- (void) func1
{
    __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
    [request setShouldContinueWhenAppEntersBackground:YES];
    [request setCompletionBlock:^{
        [self func2];
    }];
    [request startAsynchronous];
}

- (void) func2
{
    //like func1 
    ....
    [self func3];

}

- (void) func3
{
    __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
    [request setShouldContinueWhenAppEntersBackground:YES];
    [request setCompletionBlock:^{
        //Handling Local Notifications if app is in background
    }];
    [request startAsynchronous];
}

I tried to wrap every method using next code and when the app is in background the last request function never complete: dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, (unsigned long)NULL), ^(void) { ..func's scope.. }];

For a sample code see http://stackoverflow.com/questions/8861390/ios-background-downloads-when-the-app-is-not-active/8861677#8861677 — Ricardo Rivaldo, Oct 10 '12 at 11:45
Check this one helps : http://jayprakashdubey.blogspot.in/2014/07/execute-code-in-background.html — Jayprakash Dubey, Jul 30 '14 at 10:37

score 0 · Accepted Answer · answered Jun 20 '12 at 17:05

0

You need to use beginBackgroundTaskWithExpirationHandler for your dispatch_async, otherwise it won't run when the app is in the background.

answered Jun 20 '12 at 17:05

JosephH

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So, what if i do this and start 1 min infinity timer to send these two calls? Will my app terminate in 10 mins? – Slavcho Aug 01 '13 at 15:22

iOS: Run part of code in background

1 Answers1