学步园

iPhone在加载列表时，如果每个等待把所有列表中的数据都加载完在显示相关内容，如果列表中有一些比较大的图片，加载的时间比较长，那么给用户的效果就很差了，下面详细是一种实现动态加载图片的办法：
- (UITableViewCell *)tableView:(UITableView *)tableView
         cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:@"tag"];
    if (cell==nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle
                                       reuseIdentifier:@"tag"] autorelease];
    }   
    //表格设计
    NSDictionary* one = [array objectAtIndex:indexPath.row];
    cell.textLabel.text = [one objectForKey:@"title"];
    cell.detailTextLabel.text = [one objectForKey:@"content"];
     [NSThread detachNewThreadSelector:@selector(updateImageForCellAtIndexPath:) toTarget:self withObject:indexPath];
    return cell;
}
- (void)updateImageForCellAtIndexPath:(NSIndexPath *)indexPath
{
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    UIImage *image = [self getImageForCellAtIndexPath:indexPath];
    UITableViewCell *cell = [self.tableView cellForRowAtIndexPath:indexPath];
    [cell.imageView performSelectorOnMainThread:@selector(setImage:) withObject:image waitUntilDone:NO];
    [image release];
    [pool release];
}
-(UIImage *)getImageForCellAtIndexPath:(NSIndexPath *)indexPath
{
    id path = [[array objectAtIndex:indexPath.row] objectForKey:@"image"];
    NSURL *url = [NSURL URLWithString:path];
    NSData *data = [NSData dataWithContentsOfURL:url];
    UIImage *image = [[UIImage alloc] initWithData:data cache:NO];
    return image;
}