Eu tenho uma tableview com imagens grandes que preenchem as células e as alturas de linha são definidas com base no tamanho da imagem. Infelizmente, a mesa se sacode quando rola para a próxima célula.

Foi-me dito que minha tableview rolará mais suavemente se eu armazenar em cache as alturas das linhas e as imagens antes que elas sejam carregadas na tabela. Todos os meus dados são armazenados em uma plist.

Como faço para cachear algo? Como é o código e para onde ele vai?

Obrigado!

Aqui está o meu código para carregar as imagens:

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

    static NSString *detailTableViewCellIdentifier = @"Cell";

    DetailTableViewCell *cell = (DetailTableViewCell *) 
        [tableView dequeueReusableCellWithIdentifier:detailTableViewCellIdentifier];

    NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"DetailTableViewCell" owner:self options:nil];
    for(id currentObject in nib)
    {
        cell = (DetailTableViewCell *)currentObject;
    }
    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    NSString *Path = [[NSBundle mainBundle] bundlePath];
    NSString *MainImagePath = [Path stringByAppendingPathComponent:([[appDelegate.sectionsDelegateDict objectAtIndex:indexPath.section] objectForKey:@"MainImage"])];

    cell.mainImage.image = [UIImage imageWithContentsOfFile:MainImagePath];

    return cell;
}

Eu também estou usando o seguinte para calcular a altura da linha:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
    AppDelegate *appDelegate = (DrillDownAppAppDelegate *)[[UIApplication sharedApplication] delegate];
    NSString *Path = [[NSBundle mainBundle] bundlePath];
    NSString *MainImagePath = [Path stringByAppendingPathComponent:([[appDelegate.sectionsDelegateDict objectAtIndex:indexPath.section] objectForKey:@"MainImage"])];
    UIImage *imageForHeight = [UIImage  imageWithContentsOfFile:MainImagePath]; 
    imageHeight = CGImageGetHeight(imageForHeight.CGImage);  
    return imageHeight;
}

EDIT: aqui está o código final abaixo.

#define PHOTO_TAG 1
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
 static NSString *CellIdentifier = @"Photo";

 UIImageView *photo;
 UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

 AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
 UIImage *theImage = [UIImage imageNamed:[[appDelegate.sectionsDelegateDict objectAtIndex:indexPath.section] objectForKey:@"MainImage"]];

 imageHeight = CGImageGetHeight(theImage.CGImage);
 imageWidth = CGImageGetWidth(theImage.CGImage);

if (cell == nil) {
    cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    photo = [[[UIImageView alloc] initWithFrame:CGRectMake(0, 0, imageWidth, imageHeight)] autorelease];
    photo.tag = PHOTO_TAG;
    [cell addSubview:photo];
   } else {
    photo = (UIImageView *) [cell viewWithTag:PHOTO_TAG];
    [photo setFrame:CGRectMake(0, 0, imageWidth, imageHeight)];
   }

 photo.image = theImage;
 return cell;
 }