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;
}

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()

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()
            }
        }
    }
}

添加一个属性来跟踪选定的单元格

@property (nonatomic) int currentSelection;

将它设置为(例如)viewDidLoad中的哨兵值，以确保UITableView从“正常”位置开始

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.

    //sentinel
    self.currentSelection = -1;
}

在highightforrowatindexpath中，您可以为所选单元格设置所需的高度

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
    int rowHeight;
    if ([indexPath row] == self.currentSelection) {
        rowHeight = self.newCellHeight;
    } else rowHeight = 57.0f;
    return rowHeight;
}

在didSelectRowAtIndexPath中，如果需要，保存当前选择并保存动态高度

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
        // do things with your cell here

        // set selection
        self.currentSelection = indexPath.row;
        // save height for full text label
        self.newCellHeight = cell.titleLbl.frame.size.height + cell.descriptionLbl.frame.size.height + 10;

        // animate
        [tableView beginUpdates];
        [tableView endUpdates];
    }
}

在didDeselectRowAtIndexPath中将选择索引设置回哨兵值，并将单元格动画回正常形式

- (void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath {       
        // do things with your cell here

        // sentinel
        self.currentSelection = -1;

        // animate
        [tableView beginUpdates];
        [tableView endUpdates];
    }
}

我不知道连续调用beginUpdates/ endpdates是什么，你可以使用-[UITableView reloadRowsAtIndexPaths:withAnimation:]。下面是一个示例项目。

而不是beginUpdates()/ endpdates()，建议调用现在是:

tableView.performBatchUpdates(nil, completion: nil)

关于beginUpdates/ endpdates，苹果说:“尽可能使用performBatchUpdates(_:completion:)方法而不是这个方法。”

参见:https://developer.apple.com/documentation/uikit/uitableview/1614908-beginupdates