uitableview单元中的异步图像加载 [英] Asyncronous image loading in uitableview cell

问题描述

我是iPhone编程的新手.我想将图像加载到UITableView中.我的图片来自网络.我知道我必须使用 ASIHttp Request ，然后将图像加载到UITableview.但是，如果我这样做，则直到其加载图像UITableview挂起.如果我使用异步图像加载块，则每次 Cell == nil 或重用请求女佣时，我都不想这样做.

I am new in iPhone programming. I want to load images in to the UITableView. My images came from the web. I know that I must use ASIHttp Request and then load images to the UITableview. But if I do that then until its load images UITableview hang. If I use asynchronous image loading block then each time when Cell==nil or Reuse the request maid, that I doesn't want to do.

以下是我在Tableview中使用的代码行 cellForRowAtIndexpath .

Following line of code I am using in Tableview cellForRowAtIndexpath.

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

        static NSString *CellIdentifier = @"CellIdentifier";

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

        if (cell == nil) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
            cell.accessoryType=UITableViewCellAccessoryNone;



                   imgViewCellBg = [[UIImageView alloc] initWithFrame:CGRectMake(0,0,320,151)];
                   imgViewCellBg.userInteractionEnabled = NO;
                     imgViewCellBg.backgroundColor = [UIColor whiteColor];
                   imgViewCellBg.tag = 10000;
                   [cell.contentView addSubview:imgViewCellBg];
                   [imgViewCellBg release];

         }
       else{
                   imgViewCellBg = (UIImageView *)[cell.contentView viewWithTag:10000];
            }


     //-------------------------------- For the image Downloding And Displaying ------
            __block ASIHTTPRequest *request = [ASIHTTPRequest requestWithURL:[NSURL URLWithString:(MY Url)]];
            [request setCompletionBlock:^{
                // NSLog(@"Image downloaded.");
                NSData *data = [request responseData];
                UIImage *imageCountry = [[UIImage alloc] initWithData:data];

                [imgViewCellBg setImage:imageCountry];
                imageCountry = Nil;

            }];
            [request setFailedBlock:^{
                NSError *error = [request error];
                NSLog(@"Error downloading image: %@", error.localizedDescription);
            }];
            [request startAsynchronous];
            //-----------------------------------------------------------------


 return cell;

推荐答案

这是 AysncImageView 的示例，您可以从

This is an example with AysncImageView, you can download this class from AynchImageView with Example

您可以像下面的代码一样访问此类.

You can access this class like bellow code.

- (UITableViewCell *)tableView:(UITableView *)tableView

           cellForRowAtIndexPath:(NSIndexPath *)indexPath {

        static NSString *CellIdentifier = @"ImageCell";
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

        if (cell == nil) {
            cell = [[[UITableViewCell alloc]
                  initWithFrame:CGRectZero reuseIdentifier:CellIdentifier]
                  autorelease];
        } else {
        AsyncImageView* oldImage = (AsyncImageView*)
                 [cell.contentView viewWithTag:999];
        [oldImage removeFromSuperview];
        }

        CGRect frame;
        frame.size.width=75; frame.size.height=75;
        frame.origin.x=0; frame.origin.y=0;
        AsyncImageView* asyncImage = [[[AsyncImageView alloc]
                   initWithFrame:frame] autorelease];
        asyncImage.tag = 999;
        NSURL* url = [imageDownload
                   thumbnailURLAtIndex:indexPath.row];
        [asyncImage loadImageFromURL:url];

        [cell.contentView addSubview:asyncImage];

        return cell;
    }

希望这对您有所帮助.

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