CODEWITHSUNDEEP
iosobjective-c
Evgeniy Kleban
Evgeniy Kleban

Reputation: 6940

Table view move sharply when loading new images on scrolling

I have custom class that load jSON data from server, and when that data is loaded, i load image for each cell using AFNetworking. However, there is annoying effect of sharping, not smoothy scrolling, when i scroll down to new images to be load. There is my method:

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

    //Create cell

    static NSString *cellIdentifier = @"cell";

    MyCell *cell = (MyCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"MyCellView" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }

    // Check condition, either we got objects

    if (!isDataLoaded){

        cell.myActivityIndicator = [[UIActivityIndicatorView alloc]
                        initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];

        cell.myActivityIndicator.center=self.view.center;
        [cell.myActivityIndicator startAnimating];
        [self.view addSubview:cell.myActivityIndicator];

        NSLog(@"Current loading");

    }   else {

        // Hide acitivity indicator



        // Set image

//            dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_BACKGROUND, 0), ^{
//                
//                 data = [[NSData alloc] initWithContentsOfURL:[[self.objectsToShow objectAtIndex:indexPath.row]valueForKey:@"low_resolutionImage"]];
//                    UIImage *image = [[UIImage alloc] initWithData:data];
//                
//                    dispatch_async(dispatch_get_main_queue(), ^{
//                        
//                        cell.myActivityIndicator.hidden = YES;
//                        [cell.myActivityIndicator removeFromSuperview];
//                        
//                        [cell.myImageView setImage:image];
//                    });
//                
//            });

        [cell.myImageView setImageWithURL:[[self.objectsToShow objectAtIndex:indexPath.row]valueForKey:@"low_resolutionImage"]];

    }

    return cell;
}

Upvotes: 0

Views: 64

Answers (1)

Dino Tw
Dino Tw

Reputation: 3321

You don't want to download(async download is MUST) the image every time when the table cell is about to show. Instead, you save the image in a data model after it's downloaded for the first time. Afterward, you can simply retrieve the image from the model. I normally use NSMutableArray to implement the model because it's easier to add/remove its elements.

Upvotes: 1

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