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POUI hanging on background rss parsing
 

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  1. POUI hanging on background rss parsing
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    <p>I'm trying to create a simple rss reader. The code works okay, except the UI hangs when the feeds are being updated. I thought I cobbled together the code to get the feed and parse it on a background queue while updating the UI on the mainQueue, but the table hangs pretty badly. Code below:</p> <pre><code> -(void)refreshFeed2 { NSOperationQueue *queue = [[NSOperationQueue alloc] init]; for (NSString *feed in _feeds) { // iterate over all feeds NSLog(@"feed=%@", feed); NSURL *url = [NSURL URLWithString:feed]; // Create url connection and fire request NSURLConnection *conn = [[NSURLConnection alloc] init]; NSURLRequest *request = [NSURLRequest requestWithURL:url]; (void)[conn initWithRequest:request delegate:self]; [NSURLConnection sendAsynchronousRequest:request queue:queue completionHandler:^(NSURLResponse *response, NSData *data, NSError *error) { NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response; if ([data length] == 0 &amp;&amp; error == nil) { // handle empty response } else if (error != nil) { // handle error NSLog(@"Error %@", [error localizedDescription]); } else if ([httpResponse statusCode] == 200) { // data present and no errors [queue addOperationWithBlock:^{ // parse feed on queue RXMLElement *rss = [RXMLElement elementFromXMLData:data]; RXMLElement *rssChild = [rss child:@"channel"]; RXMLElement* title = [rssChild child:@"title"]; NSArray* items = [[rss child:@"channel"] children:@"item"]; NSMutableArray* result=[NSMutableArray array]; for (RXMLElement *e in items) { // iterate over the articles RSSArticle* article = [[RSSArticle alloc] init]; article.sourceTitle = [title text]; article.articleTitle = [[e child:@"title"] text]; article.articleDescription = [[e child:@"description"] text]; article.articleUrl = [NSURL URLWithString: [[e child:@"link"] text]]; NSString *articleDateString = [[e child:@"pubDate"] text]; article.articleDate = [NSDate dateFromInternetDateTimeString:articleDateString formatHint:DateFormatHintRFC822]; if (article.articleUrl != NULL) { [result addObject:article]; } } [[NSOperationQueue mainQueue] addOperationWithBlock:^{ // update table on mainQueue for (RSSArticle *article in result) { // iterate over articles int insertIdx = [_allEntries indexForInsertingObject:article sortedUsingBlock:^(id a, id b) { RSSArticle *entry1 = (RSSArticle *) a; RSSArticle *entry2 = (RSSArticle *) b; return [entry1.articleDate compare:entry2.articleDate]; }]; [_allEntries insertObject:article atIndex:insertIdx]; [self.LeftTableView insertRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:insertIdx inSection:0]] withRowAnimation:UITableViewRowAnimationFade]; } }]; }]; } }]; // Stop refresh control [refreshControl endRefreshing]; } } </code></pre> <p>Code that calls refreshFeed2:</p> <pre><code>- (void)viewDidLoad { [super viewDidLoad]; self.allEntries = [NSMutableArray array]; self.feeds = [NSArray arrayWithObjects: @"http://feeds.washingtonpost.com/rss/politics", @"http://rss.cnn.com/rss/cnn_allpolitics.rss", @"http://www.npr.org/rss/rss.php?id=1012", @"http://www.slatedigital.com/support/feeds/rss_kb.php?s=fd5aa35e773dc3177b85a2126583f002", nil]; } //add refresh control to the table view refreshControl = [[UIRefreshControl alloc] init]; [refreshControl addTarget:self action:@selector(refreshInvoked:forState:) forControlEvents:UIControlEventValueChanged]; NSString* fetchMessage = [NSString stringWithFormat:@"Fetching Articles"]; refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:fetchMessage attributes:@{NSFontAttributeName:[UIFont fontWithName:@"Helvetica" size:11.0]}]; [self.LeftTableView addSubview: refreshControl]; [self refreshInvoked:self forState:UIControlStateNormal]; } -(void) refreshInvoked:(id)sender forState:(UIControlState)state { NSOperationQueue *refreshQueue = [[NSOperationQueue alloc] init]; [refreshQueue addOperationWithBlock:^{ [self refreshFeed2]; }]; } </code></pre> <p>Any help?</p> <p>Thanks!</p>
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    1. USuser2560541
    1. USuser2560541
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    1. COhow are you calling refreshFeed2 method?
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      1. POUI hanging on background rss parsing
      1. USsatheeshwaran
    2. COI updated my original post with the code that calls refreshFeed2. It is called from viewDidLoad and from a method attached to the refreshControl in the table.
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      1. POUI hanging on background rss parsing
      1. USuser2560541
    3. COyou are making the refreshFeed2 function in the main thread, run it in a background thread to not block the UI.
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      1. USsatheeshwaran
 

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