在UITableViewCell AutoLayout中的UITextView对齐问题

Question

我正在设计一个看起来像这样的iOS屏幕：

我想做什么：

1. 用户开始编辑时应该是文本视图的文本大小。编辑完成后，它应该恢复到正常大小。

2. 当用户正在编辑textview时，文本视图的全文应该是可见的，而在其他情况下，最多可以看到两行。

3. 编辑进行时，应根据文本视图的大小维护UITableViewCell的大小。

这是我的代码：

- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
  NSString *reuseIdentifier = kRateViewCellID;
  if (!self.customCell) {
    self.customCell = [tableView dequeueReusableCellWithIdentifier:reuseIdentifier];
  }

  self.customCell.productDetailLabel.text =  @"Hello the product Name goes here so you can mention it here";
  self.customCell.commentTextView.text = [testData objectAtIndex:indexPath.row];

  // Configure the cell for this indexPath
  self.customCell.commentTextView.font = [UIFont openSansRegularFontWithSize:12];
  self.customCell.commentTextView.textContainer.maximumNumberOfLines = 2;
  self.customCell.commentTextView.textContainer.lineBreakMode = NSLineBreakByTruncatingTail;
  [self.customCell.commentTextView setScrollEnabled:NO];
  if(indexPath.row == selectedIndex) {
    self.customCell.commentTextView.textContainer.maximumNumberOfLines = 0;
    self.customCell.commentTextView.font = [UIFont openSansRegularFontWithSize:16];
    self.customCell.commentTextView.textContainer.lineBreakMode = NSLineBreakByCharWrapping;
  }
  [self.customCell.commentTextView sizeToFit];
  [self.customCell setNeedsLayout];
  [self.customCell layoutIfNeeded];
  CGFloat height = [self.customCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height;
  height += 1;

  return height;
}

- (BOOL)textViewShouldBeginEditing:(UITextView *)textView {
  textView.textContainer.maximumNumberOfLines = 0;
  textView.textContainer.lineBreakMode = NSLineBreakByCharWrapping;
  textView.font = [UIFont openSansRegularFontWithSize:16];
  selectedIndex = (int)textView.tag;
  [self performSelector:@selector(scrollTextViewToBottom:) withObject:textView afterDelay:0.01];

  return YES;
}

- (void)textViewDidBeginEditing:(UITextView *)textView {
  [self resizeTableView];
}

- (void)textViewDidChange:(UITextView *)textView {
  [testData replaceObjectAtIndex:textView.tag withObject:textView.text]  ;
  [self resizeTableView];
}


- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text {
  if([text isEqualToString:@"\n"]) {
    [self.view endEditing:YES];
    selectedIndex = -1;
    [self resizeTableView];
    return NO;
  }
  return YES;
}

- (void)textViewDidEndEditing:(UITextView *)textView {
  textView.textContainer.maximumNumberOfLines = 2;
  textView.textContainer.lineBreakMode = NSLineBreakByTruncatingTail;
  textView.font = [UIFont openSansRegularFontWithSize:12];
  [testData replaceObjectAtIndex:textView.tag withObject:textView.text];
}

- (void)scrollToCursorForTextView: (UITextView*)textView {
  CGRect cursorRect = [textView caretRectForPosition:textView.selectedTextRange.start];
  cursorRect = [self.feedbackTableView convertRect:cursorRect fromView:textView];
  if (![self rectVisible:cursorRect]) {
    [self.feedbackTableView scrollRectToVisible:cursorRect animated:YES];
  }
}

- (BOOL)rectVisible: (CGRect)rect {
  CGRect visibleRect;
  visibleRect.origin = self.feedbackTableView.contentOffset;
  visibleRect.origin.y += self.feedbackTableView.contentInset.top;
  visibleRect.size = self.feedbackTableView.bounds.size;
  visibleRect.size.height -= self.feedbackTableView.contentInset.top +     self.feedbackTableView.contentInset.bottom;

  return CGRectContainsRect(visibleRect, rect);
}

-(void)scrollTextViewToBottom:(UITextView *)textView {
  [textView setSelectedRange:NSMakeRange([textView.text length], 0)];
  [textView setScrollEnabled:NO];
  [self scrollToCursorForTextView:textView];
}

- (void)resizeTableView {
  [self.feedbackTableView beginUpdates];
  [self.feedbackTableView endUpdates];
}

我面临的问题是，每当我在textview中更改字符时，单元格的大小会发生变化，textview和contentview bottom之间的差距会增大。

任何想法如何解决这个问题。