NSURLConnection , webservices not working in Background ios - ios

Question

i am new in ios , i want to make one app , in app i have to call a webservices in background ,
background code is working properly but when i try to call webservices not go to on "connectionDidFinishLoading" function
where i doing a mistake please Help me
Here is my code
1. this is my background function each 30 sec its call webservices
- (void)applicationDidEnterBackground:(UIApplication *)application
{
if ([[UIDevice currentDevice] respondsToSelector:#selector(isMultitaskingSupported)]) { //Check if our iOS version supports multitasking I.E iOS 4
if ([[UIDevice currentDevice] isMultitaskingSupported]) { //Check if device supports mulitasking
UIApplication *application = [UIApplication sharedApplication]; //Get the shared application instance
__block UIBackgroundTaskIdentifier background_task; //Create a task object
background_task = [application beginBackgroundTaskWithExpirationHandler: ^ {
[application endBackgroundTask: background_task]; //Tell the system that we are done with the tasks
background_task = UIBackgroundTaskInvalid; //Set the task to be invalid
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
//Perform your tasks that your application requires
while(TRUE)
{
//backgroundTimeRemaining time does not go down.
// NSLog(#"Background time Remaining: %f",[[UIApplication sharedApplication] backgroundTimeRemaining]);
[UIApplication sharedApplication].applicationIconBadgeNumber++;
NSLog(#"\n\nRunning in the background!\n\n");
[self CallWebservices2];
[NSThread sleepForTimeInterval:30]; //wait for 1 sec
}
[application endBackgroundTask: background_task];
background_task = UIBackgroundTaskInvalid;
});
}
}}
2.this is my call webservices, this code reach to CallWebservices2 function but no able to call connectionDidFinishLoading
-(void)CallWebservices2
{
NSString *urlString = [NSString stringWithFormat:#"http://yournurses.com/process/push.php?action=select_jobs&id=241"];
NSLog(#"String Url = %#",urlString);
NSURL *url = [NSURL URLWithString:urlString];
NSURLRequest *urlRequest = [NSURLRequest requestWithURL:url];
NSURLConnection *connnection = [[NSURLConnection alloc] initWithRequest:urlRequest delegate:self];
[connnection start];
}
-(void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error{
NSLog(#"Error==%#",error);
}
-(void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
[nsUrlResponseDataNurse setLength:0];
}
-(void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[nsUrlResponseDataNurse appendData:data];
}
-(void)connectionDidFinishLoading:(NSURLConnection *)connection
{
if ([nsUrlResponseDataNurse length]==0)
{}
else{
NSString *str = [[NSString alloc]initWithData:nsUrlResponseDataNurse encoding:NSUTF8StringEncoding];
allDataNurse = [str JSONValue];
NSLog(#"%#",allDataNurse);
}
}
here i define in delegate.h file
#property(nonatomic,retain)NSMutableData *nsUrlResponseDataNurse;
#property(nonatomic, retain) NSMutableArray *allDataNurse;
Regards,
Nishant Chandwani

Answer 1

NSURLConnection supports async network transactions "out of the box". You should not run NSURLConnection from the background. It is pointless and wasteful. The class is designed to handle background downloading efficiently.
You create an NSURLConnection on the main thread and start it running. It does it's work in the background, then calls your delegate methods on the main thread.
If you only need to get notified when the download/PUT is complete, you can use the NSURLConnection class method sendAsynchronousRequest:queue:completionHandler: which runs the whole request, then calls your completion handler once it's done. Generally you have that method call your completion handler on the main queue, since that code gets called once the URL request is finished.
Your code might look like this:
NSURL *url = [NSURL URLWithString: #"http://www.foo.php"];
NSURLRequest *request = [NSURLRequest requestWithURL: url];
[NSURLConnection sendAsynchronousRequest: request
queue: [NSOperationQueue mainQueue]
completionHandler: ^(NSURLResponse *response,
NSData *data,
NSError *connectionError)
{
if (data.length > 0 && connectionError == nil)
{
//The data for the response is in "data" Do whatever is required
}
}
];
That code will run the request in the background, and invoke the code in the completion block once it's finished. Simple and painless.

Answer 2

Asynchronous NSURLConnection call doesn't work in different runloop but mainRunLoop. Either use synchronous request in a different thread like :-
-(void)CallWebservices2
nsUrlResponseDataNurse = [NSURLConnection sendSynchronousRequest: returningResponse: error:]
}
, or if you badly want to make your code working, change the calls to :
[[NSURLConnection alloc] initWithRequest:urlRequest delegate:self startImmediately:NO];
[connnection scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];