Question

Table view cell management has driving me crazy from past two days. Please check the code below and I will explain you the problem in detail..

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


    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    UILabel *nameLabel,*sugarLabel,*searchNameLabel,*searchSugarLabel;

    if (cell == nil) {
    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
        CGFloat width = [UIScreen mainScreen].bounds.size.width - 50;
        CGFloat height = 20;
        CGRect frame = CGRectMake(10.0f, 10.0f, width, height);
        if(isSearchOn)
        {
            searchNameLabel = [[UILabel alloc] initWithFrame:frame];
            searchNameLabel.textColor = [UIColor blackColor];
            searchNameLabel.backgroundColor = [UIColor clearColor];
            searchNameLabel.textAlignment = UITextAlignmentLeft;
            searchNameLabel.font = [UIFont systemFontOfSize:14.0f];
            searchNameLabel.tag=260;
            [cell.contentView addSubview:searchNameLabel];
            [searchNameLabel release];

            searchSugarLabel= [[UILabel alloc] initWithFrame:frame];
            searchSugarLabel.textColor = [UIColor blackColor];
            searchSugarLabel.backgroundColor = [UIColor clearColor];
            searchSugarLabel.textAlignment = UITextAlignmentLeft;
            searchSugarLabel.font = [UIFont systemFontOfSize:14.0f];
            searchSugarLabel.tag=160;
            [searchSugarLabel setHidden:YES];
            [cell.contentView addSubview:searchSugarLabel];
            [searchSugarLabel release];
        }
        else{       
        nameLabel = [[UILabel alloc] initWithFrame:frame];
        nameLabel.textColor = [UIColor blackColor];
        nameLabel.backgroundColor = [UIColor clearColor];
        nameLabel.textAlignment = UITextAlignmentLeft;
        nameLabel.font = [UIFont systemFontOfSize:14.0f];
        nameLabel.tag=60;
        [cell.contentView addSubview:nameLabel];
        [nameLabel release];

        sugarLabel= [[UILabel alloc] initWithFrame:frame];
        sugarLabel.textColor = [UIColor blackColor];
        sugarLabel.backgroundColor = [UIColor clearColor];
        sugarLabel.textAlignment = UITextAlignmentLeft;
        sugarLabel.font = [UIFont systemFontOfSize:14.0f];
        sugarLabel.tag=160;
        [sugarLabel setHidden:YES];
        [cell.contentView addSubview:sugarLabel];
        [sugarLabel release];
        }
    }
    else {        

        if(isSearchOn)
        {
            searchNameLabel=(UILabel *)[cell.contentView viewWithTag:260];
            searchSugarLabel=(UILabel *)[cell.contentView viewWithTag:160];
        }
        else{
            nameLabel=(UILabel *)[cell.contentView viewWithTag:60];
            sugarLabel=(UILabel *)[cell.contentView viewWithTag:160];
        }

    }


    if (isSearchOn) { 

        cellValue = [searchResult objectAtIndex:indexPath.row]; 
        searchSugarLabel.text=cellValue.sugarId;
        NSString *searchText = [NSString stringWithFormat:@"%@ %@", cellValue.firstName, cellValue.lastName];
        searchNameLabel.text=searchText;
        NSLog(@"%@",searchNameLabel.text);
        NSLog(@"%@",searchSugarLabel.text);
    }


     else {

            NSString *contact=[contactKeys objectAtIndex:[indexPath section]];
            NSArray *contactSection=[contactNames objectForKey:contact];
            sugar=[db getSugarId:@"Contacts" bySection:contact andIndex:indexPath.row];


            NSString *cellText = [contactSection objectAtIndex:[indexPath row]];

            // split the text by the : to get an array containing { "AAA", "BBB" }
            NSArray *splitText = [cellText componentsSeparatedByString:@":"];

            // form a new string of the form "BBB AAA" by using the individual entries in the array
            NSString *contactText = [NSString stringWithFormat:@"%@ %@", [splitText objectAtIndex:1], [splitText objectAtIndex:0]];
            nameLabel.text = contactText;
            sugarLabel.text = sugar;
}
    return cell;
}

Contacts is a class which has the properties firstName,lastName and sugar id in it..I am assigning the properties of a contacts class to the variables in the database method and returning an array of contact objects. searchResult is now an array of contact objects.The problem is when I logged the contents on the console the database gets everything in it and returns an array of contacts.The contacts in the searchResult points to different memory locations but when I try to debug the cellForRowAtIndexPath method after it gets 6 contacts..the 7th contact points to the same memory location as the 1st and it repeats thus in the searchNameLabel.text it returns a null and indexPath points to nil…I think it is cell re use issue and I accept that I am very bad in that..I need to figure this out as I am going to finish off my project with this…please guys help me…

This happens only when I try to search for the contacts. It works fine when I try to load all the contacts onto the table..

Answer 1

You are initializing your subviews in the if(cell== nil) block, but in the corresponding else-block, you overwrite them again.

You should rethink your design: Do not load different views by searchon, but set their properties depending on searchon

if(cell == nil){
   //do all initializing
}

if(searchon){
    //set view/label properties for searching style
} else {
    //set view/label properties for not-searching style
}

another approach could be to have totally separated NIB files for the searchon/!searchon

if(searchon){
    static NSString *SearchOnCellIdentifier = @"SearchOnCell"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: SearchOnCellIdentifier];
    if (cell == nil){
        //load cell from extra nib
    }

} else {
    static NSString *SearchOFFCellIdentifier = @"SearchOFFCell"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier: SearchOFFCellIdentifier];
    if (cell == nil){
        //load cell from extra nib
    }
}

NOTE: I never did that and it is not tested.