Question

I follow iOS 5 by tutorials book [Newsstand Chapter] , but I have a problem with updating icon .

As I know newsstand framework has a feature to download contents from an URL and save it to the application directory for example, weather application is terminated or not this method should work , am I right ?

1- Application should download just an icon from my site, while the app is in the background
2- After download the icon file , application should replace my new icon with current icon , which is along with push notification

here is my code but nothing happens !! where should I put this line of code ? in my appDelegate or AppViewController ?

- (void)connectionDidFinishDownloading:(NSURLConnection*)connection destinationURL:(NSURL*)destinationURL {

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    [self saveFile:@"NSIcon" ofType:@"png" fromURL:@"http://website.com/NSIcon.png" inDirectory:documentsDirectory];



UIImage * newsstandImage = [self loadImage:@"NSIcon" ofType:@"png" inDirectory:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]];

   UIApplication *app = [UIApplication sharedApplication];
    [app setNewsstandIconImage:newsstandImage];

    NSLog(@"downloading...");

}

the sample code is too confusing ! with lots of codes and custom classes or delegates , I would be grateful help me to solve this issue

Thank you

EDITED :

#pragma mark ViewDidLoad 
- (void)viewDidLoad
{


    NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:@"http://website.com/NSIcon.png"]];
    NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    if(conn){
        webData = [NSMutableData data];

        UIApplication *indicator = [UIApplication sharedApplication];
        indicator.networkActivityIndicatorVisible = YES;

        NSLog(@"%@",webData);
    }

}





#pragma mark NewsStand Methods 
-(void) connection:(NSURLConnection *) connection didReceiveResponse:(NSURLResponse *) response 
{

[webData setLength:0];
}


-(void) connection:(NSURLConnection *) connection didReceiveData:(NSData *) data 
{
    NSLog(@"Download Finish");

    UIApplication *indicator = [UIApplication sharedApplication];
    indicator.networkActivityIndicatorVisible = NO;

    [webData appendData:data];
}


-(void) connection:(NSURLConnection *) connection didFailWithError:(NSError *) error 
{
    // inform the user if connection fails//
    NSLog(@"Connection failed! Error - %@ %@",[error localizedDescription],[[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);



}



- (void)connectionDidFinishDownloading:(NSURLConnection*)connection destinationURL:(NSURL*)destinationURL {

    UIApplication *indicator = [UIApplication sharedApplication];
    indicator.networkActivityIndicatorVisible = NO;

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *documentsDirectory = [paths objectAtIndex:0];
    [self saveFile:@"NSIcon" ofType:@"png" fromURL:@"http://website.com/NSIcon.png" inDirectory:documentsDirectory];

    UIImage * newsstandImage = [self loadImage:@"NSIcon" ofType:@"png" inDirectory:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]];

    UIApplication *app = [UIApplication sharedApplication];
    [app setNewsstandIconImage:newsstandImage];

    NSLog(@"downloading...");

}

2012-04-03 23:35:11.297 iMag[6757:15803] -[__NSCFDictionary setLength:]: unrecognized selector sent to instance 0x85acfd0
(lldb)

Answer 1

connectionDidfinishDownloading is called when you when you create a connection. Example:

NSURLConnection *conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];
    if(conn){
        webData = [NSMutableData data];
        [Loading startAnimating];

        NSLog(@"%@",webData);
    }

Put these 4 in view controller

-(void) connection:(NSURLConnection *) connection didReceiveResponse:(NSURLResponse *) response 
    {
        [webData setLength: 0];
    }


// This method is responsible for storing the newly received data. The new data is appended to the NSMutableData object created in the button method, or the method that calls NSRUL methods.
-(void) connection:(NSURLConnection *) connection didReceiveData:(NSData *) data 
{
    [webData appendData:data];
}




//If an error is encountered during the download, the delegate receives a connection:didFailWithError: message. The NSError object passed as the parameter specifies the details of the error. It also provides the URL of the request that failed in the user info dictionary using the key NSURLErrorFailingURLStringErrorKey.
-(void) connection:(NSURLConnection *) connection didFailWithError:(NSError *) error 
{
    // inform the user if connection fails//
    NSLog(@"Connection failed! Error - %@ %@",[error localizedDescription],[[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);



}




   //Finally, if the connection succeeds in downloading the request, the delegate receives the connectionDidFinishLoading: message
    - (void)connectionDidFinishDownloading:(NSURLConnection*)connection destinationURL:(NSURL*)destinationURL {

//[webView loadRequest:request];//if you wanted load the website into the webview

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);


   NSString *documentsDirectory = [paths objectAtIndex:0];
    [self saveFile:@"NSIcon" ofType:@"png" fromURL:@"http://website.com/NSIcon.png" inDirectory:documentsDirectory];



UIImage * newsstandImage = [self loadImage:@"NSIcon" ofType:@"png" inDirectory:[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) objectAtIndex:0]];

   UIApplication *app = [UIApplication sharedApplication];
    [app setNewsstandIconImage:newsstandImage];

    NSLog(@"downloading...");

}