empty tableview rows when parsing with NSXMLPaerser using ASIHTTPRequest

Question

I'm pretty new iPhone development and i have a problem. After several hours of searching and digging in the code I could understand the source of the problem (hope) but do not know how to solve it. the problem is that the tableView cells loads before the parser is finish so the "[array count]" is nil. When I set the 'number of rows in section' manually, the table does appear, but only after a few sec and scrolling up and down.

i have 2 classes, one for XMLParser and one for show the tableView. According to what I read before I opened this question is that i need to reload the tavleview data but becuase i have 2 various classes i dont know how to do that. any ideas?

Thanks in davance!

here is my XMLParser code:

- (void)parserDidStartDocument:(NSXMLParser *)parser
{ 
    self.titles = [[NSMutableArray alloc]init];
    self.descriptions = [[NSMutableArray alloc]init];
    self.links = [[NSMutableArray alloc]init];
    self.pubDate = [[NSMutableArray alloc]init]; 
}

- (void)parserDidEndDocument:(NSXMLParser *)parser
{

}

BOOL isItem = NO;
BOOL isTitle = NO;
BOOL isDesription = NO;
BOOL isImg = NO;
BOOL isPubDate = NO;

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName attributes:(NSDictionary *)attributeDict
{
    if ([elementName isEqualToString:@"item"]) {
        isItem = YES;
    }

    if ([elementName isEqualToString:@"title"]) {
        isTitle=YES;
        self.titlesString = [[NSMutableString alloc]init];
    }

    if ([elementName isEqualToString:@"description"]) {
        isDesription = YES;
        self.descriptionString = [[NSMutableString alloc]init];;
        self.data = [NSMutableData data];
    }
    if ([elementName isEqualToString:@"pubDate"]) {
        isPubDate = YES;
        self.pubDateString = [[NSMutableString alloc]init];
    }

}

- (void)parser:(NSXMLParser *)parser foundCharacters:(NSString *)string{
    if(isItem && isTitle){
        [self.titlesString appendString:string];
    }
    if (isItem && isDesription) {
        [self.descriptionString appendString:string];
    }
    if (isItem && isPubDate) {
        [self.pubDateString appendString:string];
    }


}

- (void)parser:(NSXMLParser *)parser foundCDATA:(NSData *)CDATABlock
{
    if (self.data)
        [self.data appendData:CDATABlock];

}


- (void)parser:(NSXMLParser *)parser didEndElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qName
{



    if ([elementName isEqualToString:@"item"]) {
        isItem = NO;



        [self.titles addObject:self.titlesString];
        [self.descriptions addObject:self.descriptionString];
        [self.pubDate addObject:self.pubDateString];
        NSLog(@"%@,%@,%@,",self.titlesString,self.descriptionString,self.pubDate);

    }

    if ([elementName isEqualToString:@"title"]) {
        isTitle=NO;

    }
    if ([elementName isEqualToString:@"description"]) {
        isDesription = NO;


        if ([self.data length] > 0)
        {
            NSString *htmlSnippet = [[NSString alloc] initWithData:self.data encoding:NSUTF8StringEncoding];
            NSString *imageSrc = [self firstImgUrlString:htmlSnippet];
            [self.links addObject:imageSrc];
        }

        self.data = nil;
    }

    if([elementName isEqualToString:@"pubDate"])
        isPubDate = NO;
}

- (NSString *)firstImgUrlString:(NSString *)string
{
    NSError *error = NULL;
    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:@"()+?"
                                                                           options:NSRegularExpressionCaseInsensitive
                                                                             error:&error];

    NSTextCheckingResult *result = [regex firstMatchInString:string
                                                     options:0
                                                       range:NSMakeRange(0, [string length])];

    if (result)
        return [string substringWithRange:[result rangeAtIndex:2]];

    return nil;

}

and here's my show tableView code:

- (void)viewDidLoad
{
    [super viewDidLoad];

       self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"menuButton.png"] style:UIBarButtonItemStyleBordered target:self.viewDeckController action:@selector(toggleLeftView)];

    NSURL *url;

    if (!self.isGetLink)
        url = [NSURL URLWithString:@"http://www.ynet.co.il/Integration/StoryRss2.xml"];
    else
        url = [NSURL URLWithString:self.linkForParsingString];


    if (!self.xmlParser) {
        self.xmlParser = [[XMLparser alloc]init];

        [self.xmlParser LoadXMLWithURl:url];
    }

    self.isGetLink = NO;
}


- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{

    // Return the number of sections.
    return 1;
}
- (void)registerNib:(UINib *)nib forCellReuseIdentifier:(NSString *)identifier
{

}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return [self.xmlParser.titles count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{


    static NSString *CellIdentifier = @"CustomCell";
    CustomCell *cell = (CustomCell*) [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"CustomCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];

    }

    cell.lblTitle.text = [self.xmlParser.titles objectAtIndex:indexPath.row];
    cell.lblTitle.font = [UIFont boldSystemFontOfSize:[UIFont systemFontSize]];
    NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:[self.xmlParser.links objectAtIndex:indexPath.row]]];
    cell.imgView.image = [UIImage imageWithData:data];


    return cell;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return 82;
}


#pragma mark - Table view delegate
NSString *curnentDes;
NSString *currentTitle;
NSString *currentPubDate;

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{

    ReadViewController *rvc = [[ReadViewController alloc]initWithNibName:@"ReadViewController" bundle:nil];
    curnentDes = [self.xmlParser.descriptions objectAtIndex:indexPath.row];
    currentTitle = [self.xmlParser.titles objectAtIndex:indexPath.row];

    currentPubDate = [self.xmlParser.pubDate objectAtIndex:indexPath.row];
    NSDateFormatter *inputFormatter = [[NSDateFormatter alloc]init];

    [inputFormatter setDateFormat:@"EEE, dd MMM yyyy HH:mm:ss Z"];
    NSDate *inputDate = [inputFormatter dateFromString:currentPubDate];
    NSDateFormatter *outputFormatter = [[NSDateFormatter alloc]init];
    [outputFormatter setDateFormat:@"dd/MM/yyyy HH:mm"];
    NSString *outputDate = [outputFormatter stringFromDate:inputDate];

    rvc.description = curnentDes;
    rvc.stitle = currentTitle;
    rvc.pubDate = outputDate;


    [self.navigationController pushViewController:rvc animated:YES];

}

Satheesh · Accepted Answer

Pretty simple reload the table after your parsing is done, you are good to go. The reason your data comes after scrolling is your array is updated at a later point and then cellForRowAtIndex is called and array has content so you see rows.

Note: cellForRow is called for every row (hope you know that).

Using notification:

In your parser class

- (void)parserDidEndDocument:(NSXMLParser *)parser
{ 
  [[NSNotificationCenter defaultCenter ]postNotificationName:@"parsingComplete" object:nil];
}

In ViewDidLoad of your table view class add this code and add the other functions anywhere in ur class:

your viewDidLoad(edited)

- (void)viewDidLoad
{
[super viewDidLoad];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(parsingComplete) name:@"parsingComplete" object:nil];
 self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"menuButton.png"] style:UIBarButtonItemStyleBordered target:self.viewDeckController action:@selector(toggleLeftView)];

NSURL *url;

if (!self.isGetLink)
    url = [NSURL URLWithString:@"http://www.ynet.co.il/Integration/StoryRss2.xml"];
else
    url = [NSURL URLWithString:self.linkForParsingString];


if (!self.xmlParser) {
    self.xmlParser = [[XMLparser alloc]init];

    [self.xmlParser LoadXMLWithURl:url];
}

self.isGetLink = NO;
}

//Function to handle notification:

-(void)parsingComplete
 {
  NSLog(@"parsing results: %@",self.xmlParser.titles); 

  //change your tableViewName

  [yourTableView reloadData];
 }

//removing notification:

 -(void)dealloc
 {
 [[NSNotificationCenter defaultCenter] removeObserver:self];
 }

empty tableview rows when parsing with NSXMLPaerser using ASIHTTPRequest

Answers (2)

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