<p>类似QQ分组的样子，实现tableView的折叠与展开。其实要做这个效果我先想到的是在tableView中再嵌套多个tableView，这个想法实现起来就有点难了。</p>    <p>所以还是换个思路，把tableView的HeaderView用上了。给headerView加上手势，轻松解决折叠展开的问题。</p>    <p>直接上代码吧。</p>    <pre>  <code class="language-objectivec">@property (nonatomic, strong) UITableView *myTableView;    @property (nonatomic, strong) NSMutableArray *listArray;        // 数据源  @property (nonatomic, strong) NSMutableArray *titlesArray;     // 分组的名称  @property (nonatomic, strong) NSMutableDictionary *openSectionDict; // 记录哪个组展开</code></pre>    <pre>  <code class="language-objectivec">- (void)viewDidLoad {      [super viewDidLoad];      // 初始化tableView      _myTableView = [[UITableView alloc] initWithFrame:self.view.frame style:UITableViewStyleGrouped];      self.myTableView.delegate = self;      self.myTableView.dataSource = self;      [self.view addSubview:_myTableView];        self.openSectionDict = [[NSMutableDictionary alloc] init]; // 初始化字典      [self setUpData];  }</code></pre>    <pre>  <code class="language-objectivec">// 给数据源赋值  - (void)setUpData {      self.listArray = [NSMutableArray new];      self.titlesArray = [NSMutableArray new];      for (int i = 0; i < 5; i++) {     // 5个section          [self.titlesArray addObject:[NSString stringWithFormat:@"section %d", i]];          NSMutableArray *array = [NSMutableArray new];          for (int i = 0; i < 4; i++) {   // 每个section有4个row              [array addObject:[NSString stringWithFormat:@"row %d", i]];          }          [self.listArray addObject:array];      }  }</code></pre>    <pre>  <code class="language-objectivec">// 实现tableView的代理方法  #pragma mark - tableView dataSource  - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {      return 5;  }    - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {      if ([[self.openSectionDict valueForKey:[NSString stringWithFormat:@"%ld", section]] integerValue] == 0) {    //根据记录的展开状态设置row的数量          return 0;      } else {          return 4;      }  }    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {      UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"CELL_ID"];      if (!cell) {          cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"CELL_ID"];          cell.textLabel.text = [NSString stringWithFormat:@"row %ld", indexPath.row];      }      return cell;  }    #pragma mark - tableView delegate  - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {      return 45;  }    - (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {      return 40;  }    - (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {        UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, tableView.bounds.size.width, 40)];      view.backgroundColor = [UIColor whiteColor];      view.tag = KTAG + section;        UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(20, 0, view.bounds.size.width, view.bounds.size.height)];      label.text = self.titlesArray[section];      [view addSubview:label];        if ([[self.openSectionDict valueForKey:[NSString stringWithFormat:@"%ld", section]] integerValue] == 0) {          UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, (view.bounds.size.height - 10) / 2, 7, 10)];          imageView.image = [UIImage imageNamed:@"Triangle_right_gray"];   //  三角形小图片          [view addSubview:imageView];      } else {          UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(10, (view.bounds.size.height - 7) / 2, 10, 7)];          imageView.image = [UIImage imageNamed:@"Triangle_down_gray"];          [view addSubview:imageView];      }        UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(collegeTaped:)];      [view addGestureRecognizer:tap];        return view;  }    - (CGFloat)tableView:(UITableView *)tableView heightForFooterInSection:(NSInteger)section {        return 0.1;  }    #pragma mark - sectionHeader clicked  - (void)collegeTaped:(UITapGestureRecognizer *)sender {      NSString *key = [NSString stringWithFormat:@"%ld", sender.view.tag - KTAG];      //   给展开标识赋值      if ([[self.openSectionDict objectForKey:key] integerValue] == 0) {          [self.openSectionDict setObject:@"1" forKey:key];      } else {          [self.openSectionDict setObject:@"0" forKey:key];      }      NSUInteger index = sender.view.tag;      NSIndexSet *set = [NSIndexSet indexSetWithIndex:index - KTAG];      [self.myTableView reloadSections:set withRowAnimation:UITableViewRowAnimationFade];  }</code></pre>    <p>最后的效果：</p>    <p> </p>    <p>来自：http://www.jianshu.com/p/04777439451f</p>    <p> </p>