在表格视图单元格内的 UIImageView 中设置图像

Posted 2023-03-04

【中文标题】在表格视图单元格内的 UIImageView 中设置图像

【英文标题】：Setting an image in a UIImageView inside a table view cell

【发布时间】：2011-05-25 07:03:18

【问题描述】：

我使用NSThread 下载了一些图像。下载完所有图片后，我必须将它们放入cell.myimageview。给我一个用户自定义方法设置图片的解决方案。

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


    static NSString *CellIdentifier = @"Cell";
    TableCell *cell = (TableCell *)[TableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) 

        cell = [[[TableCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];

    


    NSString *bedsbaths=[NSString stringWithFormat:@"Beds:%@ Baths:%@",[[AppDeleget.statuses valueForKey:@"beds"] objectAtIndex:indexPath.row],[[AppDeleget.statuses valueForKey:@"baths"] objectAtIndex:indexPath.row]];
    cell.mlsno.text=[[AppDeleget.statuses valueForKey:@"mlsno"] objectAtIndex:indexPath.row];
    cell.price.text=[[AppDeleget.statuses valueForKey:@"price"] objectAtIndex:indexPath.row];
    cell.address.text=[[AppDeleget.statuses valueForKey:@"address"] objectAtIndex:indexPath.row];
    cell.bedsbaths.text=bedsbaths;
    cell.accessoryType=UITableViewCellAccessoryDetailDisclosureButton;
return cell;


-(void)LoadImage

    for(int x=0;x<[ListPhotos count];x++)
       
        NSData *imageData =[ListPhotos objectAtIndex:x]; 
        id path = imageData;
        NSURL *url = [NSURL URLWithString:path];
        NSLog(@"%@",url);
        NSData *data = [NSData dataWithContentsOfURL:url];
        UIImage *img = [[UIImage alloc] initWithData:data];
        [self performSelectorOnMainThread:@selector(downloadDone:) withObject:img waitUntilDone:NO];
    


-(void)downloadDone:(UIImage*)img 

    // I have to set the cell here. How?        
    cell.myimageView.image=img

【参考方案1】：

在包含视图控制器中

方法tableView:cellForRowAtIndexPath:下创建新单元格时，广告代码：

cell.imageView.image = [UIImage imageNamed@"name of image.png"];

【参考方案2】：

只要保留对单元格的引用，就不会太难。我会这样处理：

- (void)downloadDone:(UIImage*)img 
    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:yourCellRow inSection:yourCellSection];
    UITableViewCell *cell = [myTableView cellForRowAtIndexPath:indexPath];
    // now you have the cell you wish to modify;
    cell.myimageView.image=img;
    [myTableView reloadData];
    // if you would prefer, you could also call [myTableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationNone]
    // if you only want to reload that specific cell;

【讨论】：

我刚刚对此进行了测试，对我来说效果很好。我用了cell.imageView.image = [UIImage imageNamed:@"testImage.png"];，但想法是一样的。尝试在downloadDone 时设置一条日志语句，上面写着NSLog(@"image is %@", img); 之类的内容，以确保图像存在。我的猜测是，图像要么不存在，要么在你设置它之前就被释放了（我们可以在找出问题后修复）

【参考方案3】：

即使你能够在downloadDone: 方法中设置它，由于可重复使用的单元格，你稍后也会遇到问题。所以设置图像的正确位置是tableView:cellForRowAtIndexPath: 本身。那么如何加载图像呢？将它们保存在数组或字典中。假设计数不变，我们可以使用NSMutableArray 对象来存储NSNull 单例对象的计数以及以后，

在tableView:cellForRowAtIndexPath:

if ( [[images objectAtIndex:indexPath.row] isMemberOfClass:[UIImage class]] ) 
    cell.myImageView.image = [images objectAtIndex:indexPath.row];

在LoadImage

for(int x=0;x<[ListPhotos count];x++)
   
    ... 
    [photos replaceObjectAtIndex:x withObject:image];
    [self performSelectorOnMainThread:@selector(downloadDone:) 
                           withObject:[NSNumber numberWithInt:x];
                        waitUntilDone:NO];

在downloadDone:

- (void)downloadDone:(NSNumber *)row 

    [self.tableView reloadRowsAtIndexPaths:[NSIndexPath indexPathForRow:[row intValue] inSection:0]
                          withRowAnimation:UITableViewRowAnimationTop];

【参考方案4】：

您可以在 cellForRowAtIndexPath 方法本身中将图像设置为图像视图。试试下面的代码：

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


    static NSString *CellIdentifier = @"Cell";
    TableCell *cell = (TableCell *)[TableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) 

        cell = [[[TableCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease];

    


    NSString *bedsbaths=[NSString stringWithFormat:@"Beds:%@ Baths:%@",[[AppDeleget.statuses valueForKey:@"beds"] objectAtIndex:indexPath.row],[[AppDeleget.statuses valueForKey:@"baths"] objectAtIndex:indexPath.row]];
    cell.mlsno.text=[[AppDeleget.statuses valueForKey:@"mlsno"] objectAtIndex:indexPath.row];
    cell.price.text=[[AppDeleget.statuses valueForKey:@"price"] objectAtIndex:indexPath.row];
    cell.address.text=[[AppDeleget.statuses valueForKey:@"address"] objectAtIndex:indexPath.row];
    cell.bedsbaths.text=bedsbaths;
    NSString *filePath = [self getImagePath];
    UIImage * img = [UIImage imageWithContentsOfFile:filePath];
    cell.myimageView.image=img;
    cell.accessoryType=UITableViewCellAccessoryDetailDisclosureButton;
    return cell;


    -(NSString *)getImagePath
    
      /*here you can get the path of your image here*/

    

【参考方案5】：

在你的 cellForRowAtIndexPath 中

UIImageView *logoImgView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 70, 55)];
logoImgView.backgroundColor = [UIColor clearColor];
 [cell.Imageview addSubview:logoImgView];
 NSMutableArray *arrChng = [[NSMutableArray alloc] init];
 [arrChng addObject:logoImgView];
 [arrChng addObject:[Array objectAtIndex:indexPath.row];
 [self performSelectorInBackground:@selector(setImagesAfterShow:) withObject:arrChng];


-(void)setImagesAfterShow:(NSMutableArray *)array

NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
NSURL *url = [NSURL URLWithString:[array objectAtIndex:1]];
NSData *data = [[NSData alloc] initWithContentsOfURL:url];
UIImageView *img = [array objectAtIndex:0];
img.image = [UIImage imageWithData:data];
[pool release];

此方法用于在后端加载图像，因此很容易平滑滚动表格

另一种使用 ASIHTTPRequest 的方法，其中图像在后端加载，使用 link 非常好。可能对你有用。