ios:customcontrol:AsyncImageView图片异步加载

AsyncImageViewDemo.m

//控件下载地址:https://github.com/nicklockwood/AsyncImageView


//imageview本身有一张默认图片，远程图片请求完后，替换为远程图片
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        //create new cell
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
        
        //common settings
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
        cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
        cell.imageView.contentMode = UIViewContentModeScaleAspectFill;
        cell.imageView.frame = CGRectMake(0.0f, 0.0f, 44.0f, 44.0f);
        cell.imageView.clipsToBounds = YES;
    }
    else
    {
        //cancel loading previous image for cell
        [[AsyncImageLoader sharedLoader] cancelLoadingImagesForTarget:cell.imageView];
    }
    
    //set placeholder image or cell won't update when image is loaded
    cell.imageView.image = [UIImage imageNamed:@"Placeholder.png"];
    
    //load the image
    cell.imageView.imageURL = [imageURLs objectAtIndex:indexPath.row];
    
    //display image path
    cell.textLabel.text = [[[imageURLs objectAtIndex:indexPath.row] path] lastPathComponent];
    
    return cell;
}

//起初每个图片显示正在加载的状态，图片加载完毕则显示该图片
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    
#define IMAGE_VIEW_TAG 99
    
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil)
    {
        //create new cell
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
        
        //add AsyncImageView to cell
        AsyncImageView *imageView = [[AsyncImageView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 44.0f, 44.0f)];
        imageView.contentMode = UIViewContentModeScaleAspectFill;
        imageView.clipsToBounds = YES;
        imageView.tag = IMAGE_VIEW_TAG;
        [cell addSubview:imageView];
        [imageView release];
        
        //common settings
        cell.selectionStyle = UITableViewCellSelectionStyleNone;
        cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
        cell.indentationWidth = 44.0f;
        cell.indentationLevel = 1;
    }
    
    //get image view
    AsyncImageView *imageView = (AsyncImageView *)[cell viewWithTag:IMAGE_VIEW_TAG];
    
    //cancel loading previous image for cell
    [[AsyncImageLoader sharedLoader] cancelLoadingImagesForTarget:imageView];
    
    //load the image
    imageView.imageURL = [imageURLs objectAtIndex:indexPath.row];
        
    //display image path
    cell.textLabel.text = [[[imageURLs objectAtIndex:indexPath.row] path] lastPathComponent];

    return cell;
}