uitableview duplicate images - iphone

Question

I have table view that showing hotels and if they favorite or not. If hostel are favorite, in hostels's row accessory view I placed image of favorite. But the image not showed only at target's hostel. I placed randomly in other cells in the tableView. Here is the code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectMake(0, 0, 320, 50) reuseIdentifier:CellIdentifier] autorelease];
}
// Set up the cell...
//First get the dictionary object
NSDictionary *dictionary = [listOfItems objectAtIndex:indexPath.section];
NSArray *array = [dictionary objectForKey:#"Countries"];
NSString *cellValue = [array objectAtIndex:indexPath.row];
cell.textLabel.text = cellValue;
if (![favorites count] == 0) {
if ([favorites containsObject:[array objectAtIndex:indexPath.row]]) {
NSUInteger indexx = [favorites indexOfObject:cellValue];
if ([[favorites objectAtIndex:indexx] isEqual:cellValue]) {
// here is the image view
UIImageView *imageView = [[UIImageView alloc] init];
[imageView setImage:[UIImage imageNamed:#"small_ItsMyFavorite.png"]];
imageView.frame = CGRectMake(276, 0, 50, 50);
[cell addSubview:imageView];
[imageView release];
}
}
}
}
}
return cell;
}
I am searching and searching, what is the problem?

Answer 1

Since UITableView is reusing cells your design has some problems.
Your adding an UIImageView to the cell, even when it is reused, so when for instance you have 50 rows and you scroll all the way down, each time a cell is reused, you are adding an UIImageView to the cell. And so flushing the memory.
Better would be to subclass UITableViewCell in which you add the UIImageView. Do not forget to override the prepareForReuse method where you would set the image of your UIImageView to nil

Answer 2

Since UITableViewCell objects are recycled, you need to add an else branch to clear off the image when the hostel is not favorite. As you currently have it, a cell that has been used to display a favorite once would contain an image forever.
if ([[favorites objectAtIndex:indexx] isEqual:cellValue]) {
// here is the image view
UIImageView *imageView = [[UIImageView alloc] init];
[imageView setImage:[UIImage imageNamed:#"small_ItsMyFavorite.png"]];
imageView.frame = CGRectMake(276, 0, 50, 50);
[cell addSubview:imageView];
[imageView release];
} else {
// Find the UIImageView in the subviews of your cell,
// and remove it from superview.
}

Answer 3

you must do something like this
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectMake(0, 0, 320, 50) reuseIdentifier:CellIdentifier] autorelease];
}
else
{
[[cell.contentView viewWithTag:999] removeFromSuperView];
}
// Set up the cell...
//First get the dictionary object
NSDictionary *dictionary = [listOfItems objectAtIndex:indexPath.section];
NSArray *array = [dictionary objectForKey:#"Countries"];
NSString *cellValue = [array objectAtIndex:indexPath.row];
cell.textLabel.text = cellValue;
if (![favorites count] == 0) {
if ([favorites containsObject:[array objectAtIndex:indexPath.row]]) {
NSUInteger indexx = [favorites indexOfObject:cellValue];
if ([[favorites objectAtIndex:indexx] isEqual:cellValue]) {
// here is the image view
UIImageView *imageView = [[UIImageView alloc] init];
[imageView setImage:[UIImage imageNamed:#"small_ItsMyFavorite.png"]];
imageView.frame = CGRectMake(276, 0, 50, 50);
imageView.tag = 999; // for example
[cell addSubview:imageView];
[imageView release];
}
}
}
}
}
return cell;
}