无法设置UITableViewCell的背景颜色

我用下面的代码自定义背景颜色：

UIColor *cellBackgroundColor = [UIColor colorWithRed:255.0 green:255.0 blue:255.0 alpha:1.0];
cell.contentView.backgroundColor = cellBackgroundColor;

但是没有出现任何结果。这行代码就运行正常：

cell.contentView.backgroundColor = [UIColor redColor];

这是什么问题？请帮忙解答一下谢谢。

cell.backgroundView.backgroundColor

可以用自定义视图完成

UIView *backgroundViewForCell = [[[UIView alloc] init] autorelease];
backgroundViewForCell.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"row-bg.png"]];
UIView *selectedBackgroundViewForCell = [[[UIView alloc] init] autorelease];
selectedBackgroundViewForCell.backgroundColor = [[UIColor blueColor] colorWithAlphaComponent:.2];
cell.backgroundView = backgroundViewForCell;
cell.selectedBackgroundView = selectedBackgroundViewForCell;

用delegates设置背景：

- (void)tableView: (UITableView*)tableView
  willDisplayCell: (UITableViewCell*)cell
forRowAtIndexPath: (NSIndexPath*)indexPath
{

   // UIImage *img = [UIImage imageNamed:@"button.png"];  // get your background image

    UIColor *cellBackgroundColor = [UIColor colorWithRed:255/255.0 green:108/255.0 blue:61/255.0 alpha:1.0]; //if you want to set color then use this line

  //  UIColor *backgroundColor = [[UIColor alloc] initWithPatternImage: img];
    cell.backgroundColor = cellBackgroundColor;
    cell.textLabel.backgroundColor = [UIColor clearColor];
    cell.detailTextLabel.backgroundColor = [UIColor clearColor];
}

然后出现的效果应该是这样：

选择一个颜色，设置为iphone中的UI颜色

Your values are between 0 and 255. Use them to create a UIColor:

    float r; float g; float b; float a;

    [UIColor colorWithRed:r/255.f
                    green:g/255.f
                     blue:b/255.f    
                    alpha:a/255.f];