在后台加载图像以优化 ios 中的加载 [英] Loading images in background to optimize the loading in ios

问题描述

我正在尝试优化我的应用程序中的负载，事实上，我的应用程序中加载了很多图像，我花了很多时间等待视图控制器打开，尤其是第一个初始视图包含很多图片.

我查看了 .

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{静态 NSString *CellIdentifier = @"Cell";UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];如果(细胞 == 零){cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];}UIImageview* iV = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 50, 50)];[iV setImageWithURL:[NSURL URLWithString:url] placeholderImage:[UIImage imageNamed:@"image_placeholder.gif"]];[cell.contentView addSubview:iV]​​;[IV释放]；}

只需清理、构建和运行.

I am trying to optimize the load in my application, in fact, I have a lot of images that loaded in my application, and I spend a lot of time waiting for a view controller to open, especially the first initial view which includes a lot of images.

I took a look at apple sample

but I cannot re-work the whole application, what I want is just to tell me specifically what should I do?, I implement?

in the tableview, where the cell is implemented cellforrowatindexpath:

 NSURL *imageURL = ......;
 NSData *imageData = [NSData dataWithContentsOfURL:imageURL];
 UIImage *imageLoad;
 imageLoad = [[UIImage alloc] initWithData:imageData];
 imageView.image = imageLoad;

could I do something?

thank you for your help!

解决方案

Yes, you can add placeholder image to it.

It will not slow down the scrolling and will load image accordingly with time.

Also import this file UIImageView+WebCache.m and MapKit Framework

Here is the link to download the files.

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
     static NSString *CellIdentifier = @"Cell";
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
        if (cell == nil) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
        }
    UIImageview*  iV = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 50, 50)];
   [iV setImageWithURL:[NSURL URLWithString:url] placeholderImage:[UIImage imageNamed:@"image_placeholder.gif"]];
   [cell.contentView addSubview:iV];
   [iV release];

}

Just clean, build and run.

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