在xcode5.1上写的代码，ios7运行良好，在IOS6模拟器，发现cell全白，折腾半天，发现原来有些区别，供后来遇到这个问题的查看
// cell.backgroundColor = aColor; ios7
//ios6
cell.backgroundView = [[UIView alloc] initWithFrame:cell.frame];
cell.backgroundView.backgroundColor = aColor;
cell.selectionStyle = UITableViewCellSelectionStyleDefault;
cell.selectedBackgroundView = [[UIView alloc] initWithFrame:cell.frame];
cell.selectedBackgroundView.backgroundColor = color;