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

       NSString *cellId = @"cell";
       UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellId];
       NSInteger lastRowIndexInSection = [tableView numberOfRowsInSection:indexPath.section] - 1;

       if (row == lastRowIndexInSection) {
              CGFloat halfWidthOfCell = cell.frame.size.width / 2;
              cell.separatorInset = UIEdgeInsetsMake(0, halfWidthOfCell, 0, halfWidthOfCell);
       }
}

实现这一点的最好方法是关闭默认的行分隔符，子类UITableViewCell，并添加一个自定义的行分隔符作为contentView的子视图-参见下面的自定义单元格，用于表示一个SNStock类型的对象，它有两个字符串属性，ticker和name:

import UIKit

private let kSNStockCellCellHeight: CGFloat = 65.0
private let kSNStockCellCellLineSeparatorHorizontalPaddingRatio: CGFloat = 0.03
private let kSNStockCellCellLineSeparatorBackgroundColorAlpha: CGFloat = 0.3
private let kSNStockCellCellLineSeparatorHeight: CGFloat = 1

class SNStockCell: UITableViewCell {

  private let primaryTextColor: UIColor
  private let secondaryTextColor: UIColor

  private let customLineSeparatorView: UIView

  var showsCustomLineSeparator: Bool {
    get {
      return !customLineSeparatorView.hidden
    }
    set(showsCustomLineSeparator) {
      customLineSeparatorView.hidden = !showsCustomLineSeparator
    }
  }

  var customLineSeparatorColor: UIColor? {
   get {
     return customLineSeparatorView.backgroundColor
   }
   set(customLineSeparatorColor) {
     customLineSeparatorView.backgroundColor = customLineSeparatorColor?.colorWithAlphaComponent(kSNStockCellCellLineSeparatorBackgroundColorAlpha)
    }
  }

  required init(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }

  init(reuseIdentifier: String, primaryTextColor: UIColor, secondaryTextColor: UIColor) {
    self.primaryTextColor = primaryTextColor
    self.secondaryTextColor = secondaryTextColor
    self.customLineSeparatorView = UIView(frame:CGRectZero)
    super.init(style: UITableViewCellStyle.Subtitle, reuseIdentifier:reuseIdentifier)
    selectionStyle = UITableViewCellSelectionStyle.None
    backgroundColor = UIColor.clearColor()

    contentView.addSubview(customLineSeparatorView)
    customLineSeparatorView.hidden = true
  }

  override func prepareForReuse() {
    super.prepareForReuse()
    self.showsCustomLineSeparator = false
  }

  // MARK: Layout

  override func layoutSubviews() {
    super.layoutSubviews()
    layoutCustomLineSeparator()
  }

  private func layoutCustomLineSeparator() {
    let horizontalPadding: CGFloat = bounds.width * kSNStockCellCellLineSeparatorHorizontalPaddingRatio
    let lineSeparatorWidth: CGFloat = bounds.width - horizontalPadding * 2;
    customLineSeparatorView.frame = CGRectMake(horizontalPadding,
      kSNStockCellCellHeight - kSNStockCellCellLineSeparatorHeight,
      lineSeparatorWidth,
      kSNStockCellCellLineSeparatorHeight)
  }

  // MARK: Public Class API

  class func cellHeight() -> CGFloat {
    return kSNStockCellCellHeight
  }

  // MARK: Public API

  func configureWithStock(stock: SNStock) {
    textLabel!.text = stock.ticker as String
    textLabel!.textColor = primaryTextColor
    detailTextLabel!.text = stock.name as String
    detailTextLabel!.textColor = secondaryTextColor
    setNeedsLayout()
  } 
}

要禁用默认的行分隔符，请使用tableView。separatorStyle = UITableViewCellSeparatorStyle.None;消费者方面相对简单，见下面的例子:

private func stockCell(tableView: UITableView, indexPath:NSIndexPath) -> UITableViewCell {
  var cell : SNStockCell? = tableView.dequeueReusableCellWithIdentifier(stockCellReuseIdentifier) as? SNStockCell
  if (cell == nil) {
    cell = SNStockCell(reuseIdentifier:stockCellReuseIdentifier, primaryTextColor:primaryTextColor, secondaryTextColor:secondaryTextColor)
  }
  cell!.configureWithStock(stockAtIndexPath(indexPath))
  cell!.showsCustomLineSeparator = true
  cell!.customLineSeparatorColor = tintColor
  return cell!
}

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

       NSString *cellId = @"cell";
       UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellId];
       NSInteger lastRowIndexInSection = [tableView numberOfRowsInSection:indexPath.section] - 1;

       if (row == lastRowIndexInSection) {
              CGFloat halfWidthOfCell = cell.frame.size.width / 2;
              cell.separatorInset = UIEdgeInsetsMake(0, halfWidthOfCell, 0, halfWidthOfCell);
       }
}

在viewDidLoad中添加这一行:

self.tableView.separatorColor = [UIColor clearColor];

在cellForRowAtIndexPath中:

适用于iOS低版本

if(indexPath.row != self.newCarArray.count-1){
    UIImageView *line = [[UIImageView alloc] initWithFrame:CGRectMake(0, 44, 320, 2)];
    line.backgroundColor = [UIColor redColor];
    [cell addSubview:line];
}

适用于iOS 7以上版本(包括iOS 8)

if (indexPath.row == self.newCarArray.count-1) {
    cell.separatorInset = UIEdgeInsetsMake(0.f, cell.bounds.size.width, 0.f, 0.f);
}

在iOS9上，我有一个问题，改变分隔符插入也会影响文本和细节标签的定位。

我用这个解出来了

override func layoutSubviews() {
    super.layoutSubviews()

    separatorInset = UIEdgeInsets(top: 0, left: layoutMargins.left, bottom: 0, right: width - layoutMargins.left)
}

你必须采取自定义单元格，并添加标签和设置约束，如标签应覆盖整个单元格区域。 并在构造函数中编写下面的行。

- (void)awakeFromNib {
    // Initialization code
    self.separatorInset = UIEdgeInsetsMake(0, 10000, 0, 0);
    //self.layoutMargins = UIEdgeInsetsZero;
    [self setBackgroundColor:[UIColor clearColor]];
    [self setSelectionStyle:UITableViewCellSelectionStyleNone];
}

也设置UITableView布局边距如下

tblSignup.layoutMargins = UIEdgeInsetsZero;