Xcode Table view Data is getting duplicated when I pull to refresh - ios

Question

Hi My data is getting duplicated every time I use the pull to refresh.. for eg. 5 initial entries in the table view are doubled to 10 with one pull to refresh and adding 5 more in the subsequent pull to refresh. How can I stop the duplication.. I would like to make sure that only new items are downloaded and existing data in the table is not downloaded again.
#implementation RootViewController
#synthesize allEntries = _allEntries;
#synthesize feeds = _feeds;
#synthesize queue = _queue;
#synthesize webViewController = _webViewController;
#pragma mark -
#pragma mark View lifecycle
- (void)addRows {
RSSEntry *entry1 = [[[RSSEntry alloc] initWithBlogTitle:#"1"
articleTitle:#"1"
articleUrl:#"1"
articleDate:[NSDate date]] autorelease];
RSSEntry *entry2 = [[[RSSEntry alloc] initWithBlogTitle:#"2"
articleTitle:#"2"
articleUrl:#"2"
articleDate:[NSDate date]] autorelease];
RSSEntry *entry3 = [[[RSSEntry alloc] initWithBlogTitle:#"3"
articleTitle:#"3"
articleUrl:#"3"
articleDate:[NSDate date]] autorelease];
[_allEntries insertObject:entry1 atIndex:0];
[_allEntries insertObject:entry2 atIndex:0];
[_allEntries insertObject:entry3 atIndex:0];
}
- (void)viewDidLoad {
[super viewDidLoad];
self.title = #"Songs";
self.allEntries = [NSMutableArray array];
self.queue = [[[NSOperationQueue alloc] init] autorelease];
self.feeds = [NSArray arrayWithObjects:
#"http://hindisongs.bestofindia.co/?feed=rss2",
nil];
self.refreshControl = [UIRefreshControl new];
self.refreshControl.attributedTitle = [[NSAttributedString alloc] initWithString:#"Pull to refresh"];
[self.refreshControl addTarget:self action:#selector(bindDatas) forControlEvents:UIControlEventValueChanged];
[self bindDatas]; //called at the first time
}
-(void)bindDatas
{
//GET YOUR DATAS HERE…
for (NSString *feed in _feeds) {
NSURL *url = [NSURL URLWithString:feed];
ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:url];
[request setDelegate:self];
[_queue addOperation:request];
}
//update the tableView
[self.tableView reloadData];
if(self.refreshControl != nil && self.refreshControl.isRefreshing == TRUE)
{
[self.refreshControl endRefreshing];
}
}
- (void)parseRss:(GDataXMLElement *)rootElement entries:(NSMutableArray *)entries {
NSArray *channels = [rootElement elementsForName:#"channel"];
for (GDataXMLElement *channel in channels) {
NSString *blogTitle = [channel valueForChild:#"title"];
NSArray *items = [channel elementsForName:#"item"];
for (GDataXMLElement *item in items) {
NSString *articleTitle = [item valueForChild:#"title"];
NSString *articleUrl = [item valueForChild:#"link"];
NSString *articleDateString = [item valueForChild:#"pubDate"];
NSDate *articleDate = [NSDate dateFromInternetDateTimeString:articleDateString formatHint:DateFormatHintRFC822];
RSSEntry *entry = [[[RSSEntry alloc] initWithBlogTitle:blogTitle
articleTitle:articleTitle
articleUrl:articleUrl
articleDate:articleDate] autorelease];
[entries addObject:entry];
}
}
}
- (void)parseAtom:(GDataXMLElement *)rootElement entries:(NSMutableArray *)entries {
NSString *blogTitle = [rootElement valueForChild:#"title"];
NSArray *items = [rootElement elementsForName:#"entry"];
for (GDataXMLElement *item in items) {
NSString *articleTitle = [item valueForChild:#"title"];
NSString *articleUrl = nil;
NSArray *links = [item elementsForName:#"link"];
for(GDataXMLElement *link in links) {
NSString *rel = [[link attributeForName:#"rel"] stringValue];
NSString *type = [[link attributeForName:#"type"] stringValue];
if ([rel compare:#"alternate"] == NSOrderedSame &&
[type compare:#"text/html"] == NSOrderedSame) {
articleUrl = [[link attributeForName:#"href"] stringValue];
}
}
NSString *articleDateString = [item valueForChild:#"updated"];
NSDate *articleDate = [NSDate dateFromInternetDateTimeString:articleDateString formatHint:DateFormatHintRFC3339];
RSSEntry *entry = [[[RSSEntry alloc] initWithBlogTitle:blogTitle
articleTitle:articleTitle
articleUrl:articleUrl
articleDate:articleDate] autorelease];
[entries addObject:entry];
}
}
- (void)parseFeed:(GDataXMLElement *)rootElement entries:(NSMutableArray *)entries {
if ([rootElement.name compare:#"rss"] == NSOrderedSame) {
[self parseRss:rootElement entries:entries];
} else if ([rootElement.name compare:#"feed"] == NSOrderedSame) {
[self parseAtom:rootElement entries:entries];
} else {
NSLog(#"Unsupported root element: %#", rootElement.name);
}
}
- (void)requestFinished:(ASIHTTPRequest *)request {
[_queue addOperationWithBlock:^{
NSError *error;
GDataXMLDocument *doc = [[GDataXMLDocument alloc] initWithData:[request responseData]
options:0 error:&error];
if (doc == nil) {
NSLog(#"Failed to parse %#", request.url);
} else {
NSMutableArray *entries = [NSMutableArray array];
[self parseFeed:doc.rootElement entries:entries];
[[NSOperationQueue mainQueue] addOperationWithBlock:^{
for (RSSEntry *entry in entries) {
int insertIdx = [_allEntries indexForInsertingObject:entry sortedUsingBlock:^(id a, id b) {
RSSEntry *entry1 = (RSSEntry *) a;
RSSEntry *entry2 = (RSSEntry *) b;
return [entry1.articleDate compare:entry2.articleDate];
}];
[_allEntries insertObject:entry atIndex:insertIdx];
[self.tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:insertIdx inSection:0]]
withRowAnimation:UITableViewRowAnimationRight];
}
}];
}
}];
}
- (void)requestFailed:(ASIHTTPRequest *)request {
NSError *error = [request error];
NSLog(#"Error: %#", error);
}
/*
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
}
*/
/*
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
}
*/
/*
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
}
*/
/*
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
}
*/
/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
// Return YES for supported orientations.
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/
#pragma mark -
#pragma mark Table view data source
// Customize the number of sections in the table view.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [_allEntries count];
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
RSSEntry *entry = [_allEntries objectAtIndex:indexPath.row];
NSDateFormatter * dateFormatter = [[[NSDateFormatter alloc] init] autorelease];
[dateFormatter setTimeStyle:NSDateFormatterMediumStyle];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
NSString *articleDateString = [dateFormatter stringFromDate:entry.articleDate];
cell.textLabel.text = entry.articleTitle;
cell.detailTextLabel.text = [NSString stringWithFormat:#"%# - %#", articleDateString, entry.blogTitle];
return cell;
}
/*
// Override to support conditional editing of the table view.
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the specified item to be editable.
return YES;
}
*/
/*
// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the row from the data source.
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
}
else if (editingStyle == UITableViewCellEditingStyleInsert) {
// Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view.
}
}
*/
/*
// Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath {
}
*/
/*
// Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the item to be re-orderable.
return YES;
}
*/
#pragma mark -
#pragma mark Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (_webViewController == nil) {
self.webViewController = [[[WebViewController alloc] initWithNibName:#"WebViewController" bundle:[NSBundle mainBundle]] autorelease];
}
RSSEntry *entry = [_allEntries objectAtIndex:indexPath.row];
_webViewController.entry = entry;
[self.navigationController pushViewController:_webViewController animated:YES];
}
#pragma mark -
#pragma mark Memory management
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Relinquish ownership any cached data, images, etc that aren't in use.
self.webViewController = nil;
}
- (void)viewDidUnload {
// Relinquish ownership of anything that can be recreated in viewDidLoad or on demand.
// For example: self.myOutlet = nil;
}
- (void)dealloc {
[_allEntries release];
_allEntries = nil;
[_queue release];
_queue = nil;
[_feeds release];
_feeds = nil;
[_webViewController release];
_webViewController = nil;
[super dealloc];
}

Answer 1

The issue is that you keep inserting object to _allEntries without ever reseting it. You will want to empty it out at some point, either when the user pulls to refresh or when the new data comes in before you add any new objects to it.
[_allEntries removeAllObjects];
Try putting it at the start of bindDatas.