如何根据 UIImageView 高度设置不同的 UITableViewCell 高度？

Posted 2023-03-04

【中文标题】如何根据 UIImageView 高度设置不同的 UITableViewCell 高度？

【英文标题】：How to set different UITableViewCell heights based on the UIImageView height?

【发布时间】：2016-01-07 12:01:12

【问题描述】：

我需要根据 uiimageview 的高度（scaledHeight 变量）设置单元格的高度 我在我的 cellForRowAtIndexPath 中从 Parse 获取图像

PFFile *userImageFile = object[@"image"];
    [userImageFile getDataInBackgroundWithBlock:^(NSData * _Nullable data, NSError * _Nullable error) 
        if (!error) 
           // UIImageView *imageView = (UIImageView *)[cell viewWithTag:1];
            UIImage *image = [UIImage imageWithData:data];
           // imageView.image = image;


            UIImageView *test = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 400, 320)];
            test.image = image;

            CGSize imgSize = image.size;
            CGFloat ratio = test.frame.size.width/imgSize.width;
            CGFloat scaledHeight = imgSize.height * ratio;

            [test setFrame:CGRectMake(0, 0, self.view.window.frame.size.width, scaledHeight)];

            NSLog(@"HEIGHT:%f",scaledHeight);

            [cell addSubview:test];

        
     progressBlock:^(int percentDone)
    

    ];

如何在heightForRowAtIndexPath 中设置scaledHeight，因为heightForRowAtIndexPath 在CellForRowAtIndexPath 之前运行？

【参考方案1】：

由于您默认异步加载图像，因此您必须在 heightForRowAtIndexPath 方法中返回一些默认值。加载图像后，您只需重新加载该特定行。现在再次调用 heightForRowAtIndexPath ，您将返回图像的实际高度。您还可以在重新加载特定行时添加一些动画，以便 UI 过渡平滑。

【讨论】：

怎么做的例子？

tableView.reloadRowsAtIndexPaths([NSIndexPath.init(forItem: 0, inSection: 0)], withRowAnimation: .Automatic)

【参考方案2】：

1.尝试在数组中设置默认高度

- (void)setDefaultRowHeights 
    self.imageHeights = [NSMutableArray arrayWithCapacity:self.imageURLs.count];
    for (int i = 0; i < self.imageURLs.count; i++) 
        self.imageHeights[i] = @(self.tableView.rowHeight);
    

2。在 cellForRowAtIndexPath 中

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
    TableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"Cell" forIndexPath:indexPath];
    NSString *imageURL = self.imageURLs[indexPath.row];
    __weak TableViewCell *weakCell = cell;
    __weak typeof(self) weakSelf = self;
    [cell.mainImageView setImageWithURLRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:imageURL]]
                              placeholderImage:[UIImage new]
                                       success:^(NSURLRequest *request, NSHTTPURLResponse *response, UIImage *image) 
                                           weakCell.mainImageView.image = image;

                                          // Calculate Heights
                                           NSInteger oldHeight = [weakSelf.imageHeights[indexPath.row] integerValue];
                                           NSInteger newHeight = (int)image.size.height;

                                           // Update table row height if image is in different size
                                           if (oldHeight != newHeight) 
                                               weakSelf.imageHeights[indexPath.row] = @(newHeight);
                                               [weakSelf.tableView beginUpdates];
                                               [weakSelf.tableView endUpdates];
                                           
                                        failure:^(NSURLRequest *request, NSHTTPURLResponse *response, NSError *error) 
                                           NSLog(@"Error:");
                                       ];

    return cell;

3.在 heightForRowAtIndexPath 中

   - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath 
        return [self.imageHeights[indexPath.row] integerValue];
    

【讨论】：

这不起作用，因为 heightForRowAtIndexPath 在 CellforRowAtIndexPath 之前加载，我在 cellForRowAtIndexPath 中下载图像

【参考方案3】：

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

    //This is for same height of image view
     uitableViewCell *cell = [tableView cellforRowAtIndexPath : indexPath];
     return cell.imageView.size.height;
   //If you have different sizes of images then store all those image in array and then calculate the height.

【讨论】：

如何计算heightForRow..内的图像高度

imageView.size.height 会给你高度。

如果在 cellForRow 中设置了 imageView，我该怎么做？

这意味着我必须将其子类化为自定义单元格？

【参考方案4】：

默认取一个 mutablearray(NSMutableArray *arrayHeights) 这个数组的对象数等于总行数。他们都设置了“0”值

和heightForRowAtIndexPath返回

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath

    return   [arrayHeights[indexPath.row] floatValue] + 50.0; // 50 is default space set it according your requirements  

现在，当您从 getDataInBackgroundWithBlock 获得结果时，将 arrayHeights 的对象替换为该特定索引的图像高度并重新加载该单元格

PFFile *userImageFile = object[@"image"];
    [userImageFile getDataInBackgroundWithBlock:^(NSData * _Nullable data, NSError * _Nullable error) 
        if (!error) 
           // UIImageView *imageView = (UIImageView *)[cell viewWithTag:1];
            UIImage *image = [UIImage imageWithData:data];
           // imageView.image = image;


            UIImageView *test = [[UIImageView alloc]initWithFrame:CGRectMake(0, 0, 400, 320)];
            test.image = image;

            CGSize imgSize = image.size;
            CGFloat ratio = test.frame.size.width/imgSize.width;
            CGFloat scaledHeight = imgSize.height * ratio;
            [arrContactList replaceObjectAtIndex:indexPath.row withObject:[NSNumber numberWithFloat:scaledHeight]];
            [test setFrame:CGRectMake(0, 0, self.view.window.frame.size.width, scaledHeight)];

            NSLog(@"HEIGHT:%f",scaledHeight);

            [cell addSubview:test];
// reload cell
        
     progressBlock:^(int percentDone)
    

    ];

【参考方案5】：

获取图像大小边界高度并将其返回到 heightForRowAtIndexPath。这将根据您的图像高度大小动态地改变您的高度。

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
  
   //Assign your url
   NSURL* aURL = [NSURL URLWithString:@"URL"];

   //get data of that url image.
   NSData* data = [[NSData alloc] initWithContentsOfURL:aURL];

   //get image 
   UIImage *image = [UIImage imageWithData:data];

   //return it's bounding height (bounds return the area of height image requires.)
   return image.bounds.height;