Swift 4及以上

将以下代码添加到tableview的didselect行委托方法中

tableView.beginUpdates()
tableView.setNeedsLayout()
tableView.endUpdates()

我使用了@Joy的精彩答案，它在ios 8.4和XCode 7.1.1上完美地工作。

如果你想让你的单元格可切换，我改变了-tableViewDidSelect如下:

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
//This is the bit I changed, so that if tapped once on the cell, 
//cell is expanded. If tapped again on the same cell, 
//cell is collapsed. 
    if (self.currentSelection==indexPath.row) {
        self.currentSelection = -1;
    }else{
        self.currentSelection = indexPath.row;
    }
        // animate
        [tableView beginUpdates];
        [tableView endUpdates];

}

我希望这些对你有帮助。

下面是我的自定义UITableView子类的代码，它在表格单元展开UITextView，而无需重新加载(和丢失键盘焦点):

- (void)textViewDidChange:(UITextView *)textView {
    CGFloat textHeight = [textView sizeThatFits:CGSizeMake(self.width, MAXFLOAT)].height;
    // Check, if text height changed
    if (self.previousTextHeight != textHeight && self.previousTextHeight > 0) {
        [self beginUpdates];

        // Calculate difference in height
        CGFloat difference = textHeight - self.previousTextHeight;

        // Update currently editing cell's height
        CGRect editingCellFrame = self.editingCell.frame;
        editingCellFrame.size.height += difference;
        self.editingCell.frame = editingCellFrame;

        // Update UITableView contentSize
        self.contentSize = CGSizeMake(self.contentSize.width, self.contentSize.height + difference);

        // Scroll to bottom if cell is at the end of the table
        if (self.editingNoteInEndOfTable) {
            self.contentOffset = CGPointMake(self.contentOffset.x, self.contentOffset.y + difference);
        } else {
            // Update all next to editing cells
            NSInteger editingCellIndex = [self.visibleCells indexOfObject:self.editingCell];
            for (NSInteger i = editingCellIndex; i < self.visibleCells.count; i++) {
                UITableViewCell *cell = self.visibleCells[i];
                CGRect cellFrame = cell.frame;
                cellFrame.origin.y += difference;
                cell.frame = cellFrame;
            }
        }
        [self endUpdates];
    }
    self.previousTextHeight = textHeight;
}

获取所选行的indexpath。重新加载表。在UITableViewDelegate的highightforrowatindexpath方法中，将所选行的高度设置为不同的高度，对于其他的则返回正常的行高度

BOOL flag;

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    flag = !flag;
    [tableView beginUpdates];
    [tableView reloadRowsAtIndexPaths:@[indexPath] 
                     withRowAnimation:UITableViewRowAnimationAutomatic];
    [tableView endUpdates];
}

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return YES == flag ? 20 : 40;
}

西蒙·李的回答。

// MARK: - Variables 
  var isCcBccSelected = false // To toggle Bcc.



    // MARK: UITableViewDelegate
func tableView(tableView: UITableView, heightForRowAtIndexPath indexPath: NSIndexPath) -> CGFloat {

    // Hide the Bcc Text Field , until CC gets focused in didSelectRowAtIndexPath()
    if self.cellTypes[indexPath.row] == CellType.Bcc {
        if (isCcBccSelected) {
            return 44
        } else {
            return 0
        }
    }

    return 44.0
}

然后在didSelectRowAtIndexPath()中

  func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    self.tableView.deselectRowAtIndexPath(indexPath, animated: true)

    // To Get the Focus of CC, so that we can expand Bcc
    if self.cellTypes[indexPath.row] == CellType.Cc {

        if let cell = tableView.cellForRowAtIndexPath(indexPath) as? RecipientTableViewCell {

            if cell.tag == 1 {
                cell.recipientTypeLabel.text = "Cc:"
                cell.recipientTextField.userInteractionEnabled = true
                cell.recipientTextField.becomeFirstResponder()

                isCcBccSelected = true

                tableView.beginUpdates()
                tableView.endUpdates()
            }
        }
    }
}