具有动态单元格高度的UITableview中的AutoLayout [英] AutoLayout in UITableview with dynamic cell height

问题描述

对于我的表格视图单元格的动态高度，我从此链接获取参考。
使用自动布局用于动态单元布局的UITableView&可变行高

这是我的tableview数据源代码和委托方法

   - （NSInteger）tableView：（UITableView *）tableView numberOfRowsInSection：（NSInteger）section; 
 {
返回arrTemp。计数; 
} 
 
  - （UITableViewCell *）tableView：（UITableView *）tableView cellForRowAtIndexPath：（NSIndexPath *）indexPath 
 {
 static NSString * cellIdentifier = @AutoLAyoutCell ; 
 
 AutoLayoutTableViewCell * cell =（AutoLayoutTableViewCell *）[tableView dequeueReusableCellWithIdentifier：cellIdentifier]; 
 if（cell == nil）{
 for（[NSBundle mainBundle] loadNibNamed中的id currentObject：@AutoLayoutTableViewCellowner：self options：nil]）{
 if（[currentObject isKindOfClass ：[UITableViewCell类]]）{
 cell =（AutoLayoutTableViewCell *）currentObject; 
休息; 
} 
} 
} 
 
 cell.IBlblLineNo.text = [NSString stringWithFormat：@Line：％i，indexPath.row]; 
 cell.IBlblLineText.text = [arrTemp objectAtIndex：indexPath.row]; 
 [cell setNeedsUpdateConstraints]; 
 [cell updateConstraintsIfNeeded]; 
 
 CGSize expectedlineLabelSize = [cell.IBlblLineText.text sizeWithFont：cell.IBlblLineText.font constrainedToSize：CGSizeMake（280,1000）lineBreakMode：NSLineBreakByTruncatingTail]; 
 cell.IBlblLineText.numberOfLines = expectedlineLabelSize.height / 17; 
 
 CGRect frmlbl = cell.IBlblLineText.frame; 
 frmlbl.size.height = expectedlineLabelSize.height; 
 cell.IBlblLineText.frame = frmlbl; 
 
返回单元格; 
} 
 
  - （CGFloat）tableView：（UITableView *）tableView heightForRowAtIndexPath：（NSIndexPath *）indexPath 
 {
 
 AutoLayoutTableViewCell * cell =（AutoLayoutTableViewCell *）[IBtblAutoLayoutExample cellForRowAtIndexPath：indexPath]; 
 
 cell.IBlblLineNo.text = [NSString stringWithFormat：@Line：％i，indexPath.row]; 
 cell.IBlblLineText.text = [arrTemp objectAtIndex：indexPath.row]; 
 
 [cell setNeedsUpdateConstraints]; 
 [cell updateConstraintsIfNeeded]; 
 
 CGSize expectedlineLabelSize = [cell.lineLabel.text sizeWithFont：cell.lineLabel.font constrainedToSize：CGSizeMake（280,1000）lineBreakMode：NSLineBreakByWordWrapping]; 
 
 cell.IBlblLineText.numberOfLines = expectedlineLabelSize.height / 17; 
 CGRect frmlbl = cell.IBlblLineText.frame; 
 frmlbl.size.height = expectedlineLabelSize.height; 
 cell.IBlblLineText.frame = frmlbl; 
 
 CGFloat height = [cell.contentView systemLayoutSizeFittingSize：UILayoutFittingCompressedSize] .height; 
 height + = 1.0f; 
 
返回高度; 
} 
 
  - （CGFloat）tableView：（UITableView *）tableView estimatedHeightForRowAtIndexPath：（NSIndexPath *）indexPath 
 {
 AutoLayoutTableViewCell * cell =（AutoLayoutTableViewCell *）[IBtblAutoLayoutExample的cellForRowAtIndexPath：indexPath]; 
 
 CGSize expectedlineLabelSize = [cell.IBlblLineText.text sizeWithFont：cell.IBlblLineText.font constrainedToSize：CGSizeMake（280,1000）lineBreakMode：NSLineBreakByTruncatingTail]; 
 
返回expectedlineLabelSize.height; 
 
} 
  

我有2个问题：

1. 我的问题是我在行附近收到错误 EXE_BAD_EXCESS / p>
   
   

     AutoLayoutTableViewCell * cell =（AutoLayoutTableViewCell *）[IBtblAutoLayoutExample cellForRowAtIndexPath：indexPath];在$ code> heightForRowAtIndexPath 和 estimatedHeightForRowAtIndexPath 。
    




2. 为什么我必须在 cellForRowAtIndexPath 和 heightForRowAtIndexPath ？




另外，我错过了为了获得单元的动态高度需要什么？

解决方案

设置行高的自动尺寸&估计行高，确保执行以下步骤，自动尺寸对单元格/行高度布局有效。

• 分配和实现tableview dataSource和委托


• 分配 UITableViewAutomaticDimension 到rowHeight& estimatedRowHeight


• 实现委托/ dataSource方法（即 heightForRowAt 并返回值 UITableViewAutomaticDimension 到它）

-

目标C：

 // ViewController.h中的$ code> // 
 #import< UIKit / UIKit.h> 
 
 @interface ViewController：UIViewController< UITableViewDelegate，UITableViewDataSource> 
 
 @property IBOutlet UITableView * table; 
 
 @end 
 
 //在ViewController.m中
 
  - （void）viewDidLoad {
 [super viewDidLoad]; 
 self.table.dataSource = self; 
 self.table.delegate = self; 
 
 self.table.rowHeight = UITableViewAutomaticDimension; 
 self.table.estimatedRowHeight = UITableViewAutomaticDimension; 
} 
 
  - （CGFloat）tableView：（UITableView *）tableView heightForRowAtIndexPath：（NSIndexPath *）indexPath {
 
返回UITableViewAutomaticDimension; 
} 
  

Swift：

  @IBOutlet弱变量表：UITableView！ 
 
覆盖func viewDidLoad（）{
 super.viewDidLoad（）
 
 //不要忘记为表
表设置dataSource和delegate。 dataSource = self 
 table.delegate = self 
 
 //设置行高的自动尺寸
 // Swift 4.2以后
 table.rowHeight = UITableView.automaticDimension 
 table.estimatedRowHeight = UITableView.automaticDimension 
 
 
 // Swift 4.1及以下
 table.rowHeight = UITableViewAutomaticDimension 
 table.estimatedRowHeight = UITableViewAutomaticDimension 
 
} 
 
 
 
 // UITableViewAutomaticDimension计算标签内容/文本的高度
 func tableView（_ tableView：UITableView，heightForRowAt indexPath：IndexPath） - > CGFloat {
 // Swift 4.2以上
返回UITableView.automaticDimension 
 
 // Swift 4.1及以下
返回UITableViewAutomaticDimension 
} 
  

对于UITableviewCell中的标签实例

• 设置行数= 0（&换行模式=截断尾部）


• 相对于其superview / cell容器设置所有约束（顶部，底部，右侧）。


• 可选：如果您希望标签覆盖最小垂直区域，即使没有数据，也要设置标签的最小高度。

注意：如果您有多个动态长度的标签（UIElements），应根据其内容大小进行调整：调整内容拥抱和压缩阻力优先级`对于要以更高优先级扩展/压缩的标签。

For dynamic height of my table view cell I take reference from this link. Using Auto Layout in UITableView for dynamic cell layouts & variable row heights

Here is my code of tableview data source and delegate methods

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section;
  {
       return arrTemp. count;
  }

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier=@"AutoLAyoutCell";

AutoLayoutTableViewCell *cell=(AutoLayoutTableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell==nil) {
    for (id currentObject in [[NSBundle mainBundle] loadNibNamed:@"AutoLayoutTableViewCell" owner:self options:nil]) {
        if ([currentObject isKindOfClass:[UITableViewCell class]]) {
            cell = (AutoLayoutTableViewCell *)currentObject;
            break;
        }
    }
}

cell.IBlblLineNo.text=[NSString stringWithFormat:@"Line:%i",indexPath.row];
cell.IBlblLineText.text=[arrTemp objectAtIndex:indexPath.row];
[cell setNeedsUpdateConstraints];
[cell updateConstraintsIfNeeded];

CGSize expectedlineLabelSize = [cell.IBlblLineText.text sizeWithFont:cell.IBlblLineText.font constrainedToSize:CGSizeMake(280, 1000) lineBreakMode:NSLineBreakByTruncatingTail];
cell.IBlblLineText.numberOfLines=expectedlineLabelSize.height/17;

CGRect frmlbl=cell.IBlblLineText.frame;
frmlbl.size.height=expectedlineLabelSize.height;
cell.IBlblLineText.frame=frmlbl;

return cell;
}

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

AutoLayoutTableViewCell *cell = (AutoLayoutTableViewCell *)[IBtblAutoLayoutExample cellForRowAtIndexPath:indexPath];

cell.IBlblLineNo.text=[NSString stringWithFormat:@"Line:%i",indexPath.row];
cell.IBlblLineText.text=[arrTemp objectAtIndex:indexPath.row];

[cell setNeedsUpdateConstraints];
[cell updateConstraintsIfNeeded];

CGSize expectedlineLabelSize = [cell.lineLabel.text sizeWithFont:cell.lineLabel.font constrainedToSize:CGSizeMake(280, 1000) lineBreakMode:NSLineBreakByWordWrapping];

 cell.IBlblLineText.numberOfLines=expectedlineLabelSize.height/17;
CGRect frmlbl=cell.IBlblLineText.frame;
frmlbl.size.height=expectedlineLabelSize.height;
cell.IBlblLineText.frame=frmlbl;

CGFloat height = [cell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
height += 1.0f;

return height;
}

- (CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath
{
     AutoLayoutTableViewCell *cell = (AutoLayoutTableViewCell *)[IBtblAutoLayoutExample cellForRowAtIndexPath:indexPath];

 CGSize expectedlineLabelSize = [cell.IBlblLineText.text sizeWithFont:cell.IBlblLineText.font constrainedToSize:CGSizeMake(280, 1000) lineBreakMode:NSLineBreakByTruncatingTail];

 return expectedlineLabelSize.height;

}

I have 2 questions :

1. My issue is I get the error EXE_BAD_EXCESS near the line

   AutoLayoutTableViewCell *cell = (AutoLayoutTableViewCell *)[IBtblAutoLayoutExample cellForRowAtIndexPath:indexPath]; 
   

   in heightForRowAtIndexPath and estimatedHeightForRowAtIndexPath.

2. Why do I have to write label text in both cellForRowAtIndexPath and heightForRowAtIndexPath?

Also, am I missing anything needed to achieve dynamic height for the cell?

解决方案

To set automatic dimension for row height & estimated row height, ensure following steps to make, auto dimension effective for cell/row height layout.

• Assign and implement tableview dataSource and delegate
• Assign UITableViewAutomaticDimension to rowHeight & estimatedRowHeight
• Implement delegate/dataSource methods (i.e. heightForRowAt and return a value UITableViewAutomaticDimension to it)

-

Objective C:

// in ViewController.h
#import <UIKit/UIKit.h>

@interface ViewController : UIViewController <UITableViewDelegate, UITableViewDataSource>

  @property IBOutlet UITableView * table;

@end

// in ViewController.m

- (void)viewDidLoad {
    [super viewDidLoad];
    self.table.dataSource = self;
    self.table.delegate = self;

    self.table.rowHeight = UITableViewAutomaticDimension;
    self.table.estimatedRowHeight = UITableViewAutomaticDimension;
}

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

    return UITableViewAutomaticDimension;
}

Swift:

@IBOutlet weak var table: UITableView!

override func viewDidLoad() {
    super.viewDidLoad()

    // Don't forget to set dataSource and delegate for table
    table.dataSource = self
    table.delegate = self

    // Set automatic dimensions for row height
    // Swift 4.2 onwards
    table.rowHeight = UITableView.automaticDimension
    table.estimatedRowHeight = UITableView.automaticDimension


    // Swift 4.1 and below
    table.rowHeight = UITableViewAutomaticDimension
    table.estimatedRowHeight = UITableViewAutomaticDimension

}



// UITableViewAutomaticDimension calculates height of label contents/text
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    // Swift 4.2 onwards
    return UITableView.automaticDimension

    // Swift 4.1 and below
    return UITableViewAutomaticDimension
}

For label instance in UITableviewCell

• Set number of lines = 0 (& line break mode = truncate tail)
• Set all constraints (top, bottom, right left) with respect to its superview/ cell container.
• Optional: Set minimum height for label, if you want minimum vertical area covered by label, even if there is no data.

Note: If you've more than one labels (UIElements) with dynamic length, which should be adjusted according to its content size: Adjust 'Content Hugging and Compression Resistance Priority` for labels which you want to expand/compress with higher priority.

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