如何在iPhone中以编程方式增加UITableView单元格的高度?

最后发布: 2014-01-28 04:35:13


问题

我有单独的自定义UITableViewCell用于显示数据(这些数据来自服务器JSON响应)。在每个UITableViewCell我有按钮阅读更多。如果用户点击阅读更多按钮我想以编程方式添加UILabel以显示来自服务器的其他信息。但最初我设置UITableViewCell高度所以点击阅读更多按钮后我无法看到额外的信息UILabel ..

这是屏幕截图:

在此输入图像描述

这是我需要的屏幕:

在此输入图像描述

这是我使用的以下编码:

-(NSInteger) numberOfSectionsInTableView:(UITableView *)tableView
{
    return 1;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{

   int height1;
    if(readMore){
        height1=200;
        NSLog(@"Clicked");
    }
    else{
        height1=100;
        NSLog(@"Not clicked");
    }
    return height1; // Normal height
}


-(NSInteger) tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section
{
    return [TitleArr  count];
}


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

    if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
    {
        static NSString *simpleTableIdentifier = @"SimpleTableCell_iPad";

        cell = (TableCell_Leads *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    }
    else{
        static NSString *simpleTableIdentifier = @"TableCell_Leads";

        cell = (TableCell_Leads *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    }
    if (cell == nil)
    {
        if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
        {
            NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"SimpleTableCell_iPad" owner:self options:nil];
            cell = [nib objectAtIndex:0];

        }
        else{
            NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"TableCell_Leads" owner:self options:nil];
            cell = [nib objectAtIndex:0];
        }
    }




    cell.labTitle.text = [TitleArr objectAtIndex:indexPath.row];

    cell.labCategory.text=[CategoryArr objectAtIndex:indexPath.row];

    [cell.btnReadmore addTarget:self
                         action:@selector(funReadmore:)
               forControlEvents:UIControlEventTouchUpInside];


    return cell;
}



 - (IBAction)funReadmore:(id)sender
    {
        [self.tableView beginUpdates];
        readMore=TRUE;



        NSLog(@"READ MORE");
        [self.tableView endUpdates];
}
ios objective-c iphone uitableview
回答

首先采用boolint变量。

BOOL isReadMoreButtonTouched = NO;
int indexOfReadMoreButton = -1;

然后使用您的代码在下面实现

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    [[cell btnReadmore] setTag:[indexPath row]];

    if(isReadMoreButtonTouched && [indexPath row]== indexOfReadMoreButton)
    {
       // design your read more label here
    }
}

现在实施IBAction

-(IBAction) funReadmore:(id)sender
{
    UIButton *readMoreButton = (UIButton *)sender;
    indexOfReadMoreButton=[readMoreButton tag];
    isReadMoreButtonTouched=YES;

    [[self tableView] beginUpdates];
    [[self tableView] reloadRowsAtIndexPaths:@[[NSIndexPath indexPathForItem: indexOfReadMoreButton inSection:0]] withRowAnimation:UITableViewRowAnimationAutomatic];
    [[self tableView] endUpdates];
}

现在来到heightForRowAtIndexPath

-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if(isReadMoreButtonTouched && [indexPath row]== indexOfReadMoreButton) return 200.0f;
    else return 100.0f;
}

希望它对你有用。


回答

取一个int readMoreAtIndex; 作为你的类变量。 init method和/或viewDidLoad/viewWillAppear使用负值(如-1)对其进行init method 一些基本逻辑是这样的:

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{   
    if(readMoreAtIndex == indexPath.row) {
        return 400; //return as per your requirement
    }
    return 100;
}

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

    //same lines as currently you are doing to setup cell.     

    //important line
    [cell.btnReadmore setTag:indexPath.row];

    [cell.btnReadmore addTarget:self
                         action:@selector(funReadmore:)
               forControlEvents:UIControlEventTouchUpInside];

    if(indexPath.row == readMoreAtIndex) {
        //setup your cell according to your logic to show expanded view
    }
    else {
        //you are reusing cells, so provide logic to disappear shown expanded view if you want
    }

    return cell;
}

- (IBAction)funReadmore:(id)sender
{     
    UIButton *button = (UIButton *)sender;
    readMoreAtIndex = button.tag;
    [yourTableView reloadData];
    NSLog(@"READ MORE");
}

编辑:实现可扩展/可折叠tableview的教程链接。

  1. 扩展/折叠TableView部分
  2. 适用于iOS的可折叠表视图


回答

我找到了另一种基于自我调整表视图单元格的解决方案。 我们可以更新约束优先级,而不是更新单元格的高度(硬编码)。

fileprivate extension Int {
   static let rowHeight = 175
}

class CellArticleData {
  var article: Article
  var isExpanded: Bool

  init(article: Article, isExpanded: Bool) {
    self.article = article
    self.isExpanded = isExpanded
  }
}

 enum Article: String {
    case medicine, sport
    static let allArticles: [Article] = [.medicine, .sport]
    var title: String { return self.rawValue.capitalized }
    var description: String {
        switch self {
          case .medicine:
            return "Lorem Ipsum is simply dummy text of the printing and 
            typesetting industry"
          case .sport:
            return "Contrary to popular belief, Lorem Ipsum is not simply 
            random text. It has roots in a piece of classical Latin 
            literature from 45 BC, making it over 2000 years old. Richard 
            McClintock, a Latin professor at Hampden-Sydney College in 
            Virginia."
      }
   }
}

class ViewController: UIViewController {

@IBOutlet weak var tableView: UITableView!
var articles: [CellArticleData] = Article.allArticles.map { CellArticleData(article: $0, isExpanded: false) }

override func viewDidLoad() {
    super.viewDidLoad()

    tableView.dataSource = self
    tableView.delegate = self
    tableView.rowHeight = UITableViewAutomaticDimension
    tableView.estimatedRowHeight = CGFloat(.rowHeight)
}

 extension ViewController: UITableViewDataSource {

 func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "MyCell", for: indexPath) as! MyCell
    let articleData = articles[indexPath.row]
    cell.setup(articleData: articleData)
    cell.delegate = self
    return cell
  }
}

extension ViewController: MyCellDelegate {

  func handleReadMore() {
      tableView.reloadData()
   }
}

我有一个自定义类,代表一个单元“MyCell”,它处理协议和约束更新:

protocol MyCellDelegate {
    func handleReadMore()
}

class MyCell: UITableViewCell {

   @IBOutlet weak var topConstraint: NSLayoutConstraint!
   @IBOutlet weak var bottomConstraint: NSLayoutConstraint!
   @IBOutlet weak var heightConstraint: NSLayoutConstraint!

  func setup(articleData: CellArticleData) {
    self.articleData = articleData

    titleLabel.text = articleData.article.title
    descriptionLabel.text = articleData.article.description
    readMoreLabel.isUserInteractionEnabled = true

    let readMoreTap = UITapGestureRecognizer(target: self, action: #selector(handleReadMore))
    readMoreTap.cancelsTouchesInView = false
    readMoreLabel.addGestureRecognizer(readMoreTap)
    updateCellConstraints()
}

fileprivate func updateCellConstraints() {
    if let articleData = self.articleData {
        if !articleData.isExpanded {
            heightConstraint.priority = 999
            topConstraint.priority = 250
            bottomConstraint.priority = 250
        }else {
            heightConstraint.priority = 250
            topConstraint.priority = 999
            bottomConstraint.priority = 999
        }

    }
  }

   func handleReadMore() {
      if let articleData = self.articleData {
         articleData.isExpanded = !articleData.isExpanded
         delegate?.handleReadMore(articleData: articleData)
     }
   }
}

下面是一个显示它的样子的示例: 我的自定义单元格MyCell


回答

你需要放置某种标志机制并管理高度

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

最好和理想的方法是根据文本计算高度,然后返回高度

 - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{       
    if(readMore){
      return 500;
     }else{
      return 100;
     }
}

如果您使用autolayout,则可以使用sizeToFit方法根据内容手动计算每个标签的大小


回答

我发布的示例代码将根据按钮单击扩展单元格,文本大小适用于iOS6和iOS 7,这只是示例代码,只需通过这个可能有助于你... :)

这只是您可以尝试的示例项目


     in customCell.h
     #import <UIKit/UIKit.h>
     @class CustomCell;
     @protocol ButtonClickDelegate <NSObject> //custom delegate
     - (void)whenReadMoreButtonClicked:(CustomCell *)cell;//i am passing the cell itself
     @end

     @interface CustomCell : UITableViewCell
     @property (nonatomic,assign)id<ButtonClickDelegate>delegate;
    @property (nonatomic,retain)UILabel *mesageLabel;
    @property (nonatomic,retain)NSString *message;
    @property (nonatomic,assign)BOOL expand;

    @end


在customCell.m中


    #import "CustomCell.h"

    @implementation CustomCell
    @synthesize delegate;//synthesize it
    @synthesize mesageLabel;
    @synthesize message;
    @synthesize expand;


    - (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
   {
      self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
      if (self) {
     // Initialization code
      UIButton *button = [[UIButton alloc]initWithFrame:CGRectMake(5,2, 100, 35)];
      [button addTarget:self action:@selector(whenButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
      [button setTitle:@"Read More" forState:UIControlStateNormal];
       button.backgroundColor = [UIColor greenColor];

      self.mesageLabel = [[UILabel alloc]initWithFrame:CGRectMake(0 , 40,0 ,0)];
       self.mesageLabel.backgroundColor = [UIColor redColor];
      self.mesageLabel.numberOfLines = 100;
      [self addSubview:self.mesageLabel];
       [self addSubview:button];
    }
     return self;
   }

  - (void)setSelected:(BOOL)selected animated:(BOOL)animated
  {
       [super setSelected:selected animated:animated];

      // Configure the view for the selected state
  }

   - (void)whenButtonClicked:(id)sender
   {
       if([self.delegate respondsToSelector:@selector(whenReadMoreButtonClicked:)])
       {
          [self.delegate whenReadMoreButtonClicked:self];//delegate to controller
       }

  }

  - (void)layoutSubviews
  {
       [super layoutSubviews];
      self.mesageLabel.text = self.message;
      if(self.expand)
      {
          CGSize size = [self findMessgeStringHeight];
          self.mesageLabel.frame = CGRectMake(0, 40, size.width, size.height);
      }
      else
      {
          self.mesageLabel.frame = CGRectMake(0, 40, self.bounds.size.width, 100);
      }

  }


   //helper method to find height
    - (CGSize)findMessgeStringHeight
     {  
         NSAttributedString *attributedText = [[NSAttributedString alloc] initWithString:self.message attributes:@{ NSFontAttributeName:[UIFont systemFontOfSize:17.0f] }];
        CGRect rect = [attributedText boundingRectWithSize:(CGSize){225, MAXFLOAT}
                                           options:NSStringDrawingUsesLineFragmentOrigin
                                           context:nil];
        CGSize requiredSize = rect.size;

         return requiredSize; //finally u return your height
     } 

     @end


在viewController中

      #import "ViewController.h"
      #import "CustomCell.h"

      @interface ViewController ( <UITableViewDataSource,UITableViewDelegate,ButtonClickDelegate>//confirm's to delegate
      {

        BOOL ButtonClickedForExpand;
        NSMutableArray *array;

     }

     @property (nonatomic,retain)NSIndexPath *previousIndexPath;
      @property (nonatomic,retain)NSIndexPath *currentIndexPath;

     @end

    @implementation ViewController
     @synthesize previousIndexPath;
    @synthesize currentIndexPath;

    - (void)viewDidLoad
     {
         [super viewDidLoad];
        ButtonClickedForExpand = NO;
// Do any additional setup after loading the view, typically from a nib.
      array = [[NSMutableArray alloc]initWithObjects:@"hello happy coding some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext",@"some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext",@"ello happy coding some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext ello happy coding some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext ello happy coding some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext ello happy coding some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext ello happy coding some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtext some longtextsome longtext some longtext", nil];
      }

    - (void)didReceiveMemoryWarning
    {
       [super didReceiveMemoryWarning];
      // Dispose of any resources that can be recreated. 
    }

    - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
   {
       return 1;
   }

    - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
   {
      return array.count;
   }
     - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
  { 
      CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CELL"];
     if(cell == nil)
      {
        cell = [[CustomCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"CELL"];
      }

     if(ButtonClickedForExpand)
     {
        if(indexPath.row == currentIndexPath.row)
        {
           cell.expand = YES;
        }
        else
       {
          cell.expand = NO;
       }
    }
    else
   {
       cell.expand = NO;
   }

    cell.message = [array objectAtIndex:indexPath.row];
    cell.delegate = self;//u need to set delegate to self
    return cell;
  }

   - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
  {
      CGSize size = [self findMessgeStringHeight:[array objectAtIndex:indexPath.row]];
     if(ButtonClickedForExpand)
      {
         if(indexPath.row == currentIndexPath.row)
         {
             return size.height + 30;
         }
        else
        {
           return 100;//by default
        }
    }
    else
     {
         return 100;
     }

  } 

    //helper function to return the correct height for your label
  - (CGSize)findMessgeStringHeight:(NSString *)str
  {

     NSAttributedString *attributedText = [[NSAttributedString alloc] initWithString:str attributes:@{ NSFontAttributeName:[UIFont systemFontOfSize:17.0f] }];
     CGRect rect = [attributedText boundingRectWithSize:(CGSize){225, MAXFLOAT}
                                           options:NSStringDrawingUsesLineFragmentOrigin
                                           context:nil];
     CGSize requiredSize = rect.size;

     return requiredSize; //finally u return your height
  }



  - (void)whenReadMoreButtonClicked:(CustomCell *)cell
 {
       ButtonClickedForExpand = YES;
       self.previousIndexPath = self.currentIndexPath;
      self.currentIndexPath = [self.tableView indexPathForCell:cell];


       [self.tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:self.currentIndexPath] withRowAnimation:UITableViewRowAnimationFade];

    if(self.previousIndexPath.row == nil)
     { 
      return;
     }
     else
     {
       [self.tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:self.previousIndexPath] withRowAnimation:UITableViewRowAnimationFade];
      }

   }


   @end


编辑:添加ButtonClickedForExpand以进行第一次单击

编辑:2改变if(self.previousIndexPath.row == nil)在视图控制器的“whenReadMoreButtonClicked”方法

如果你没有得到评论


回答

我建议你按照以下步骤操作:

在自定义单元格中,您可以使用的内容,将其放在隐藏的UIView容器中。 因此默认情况下不可见。

  1. 当按下更多按钮时,在绘制tableView的类中处理其事件触发器,因为你正在做funReadmore处理程序。

  2. 获取单元格的索引并在NSMutableArray对象中管理/添加它。

  3. 使用以下方法重新加载TableView数据:

[yourTableViewInstance reloadData];
  1. heightForRowAtIndexPath委托函数中,写如下:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if(arrayOfExpandedCellIndexes.contains(indexPath.row))    
         return EXTENDED_CELL_HEIGHT;   // Macro : #define EXTENDED_CELL_HEIGHT 230.0f 
    else 
         return NORMAL_CELL_HEIGHT;     // Macro : #define NORMAL_CELL_HEIGHT   100.0f 
}

使用这种方式,您可以按下Read More按钮处理多个单元格。 如果在您的要求中只能扩展一个单元格,请使用以下方法清除arrayOfExpandedCellIndexes

[arrayOfExpandedCellIndexes removeAllObjects];

注意:一旦为单元格调整了高度,请不要忘记使隐藏视图可见。

希望能帮助到你!