系統預設cell分割線是左邊縮排15pt
大致遇見以下幾種情況：
1.隱藏section分割線，不隱藏row分割線
特別注意初始化UITableView時style設為plain需要再section>=2的情況下才會適用。
2.
如果我們想要隱藏某條分割線或者修改分割線長短可重寫下面方法
例如：將section==1且indexpath.row==4的分割線隱藏

-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    if
 
 (indexPath.section == 1 && indexPath.row == 4) {
        if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
            [cell setSeparatorInset:UIEdgeInsetsMake(0, 0, 0, kDeviceWidth)];
        }
    }else{
        if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
            [cell set
 
SeparatorInset:UIEdgeInsetsMake(0, 15, 0, 15)];
        }

        if ([cell respondsToSelector:@selector(setPreservesSuperviewLayoutMargins:)]) {
            [cell setPreservesSuperviewLayoutMargins:NO];
        }

        if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {
            [cell set
 
LayoutMargins:UIEdgeInsetsMake(0, 15, 0, 15)];
        }
    }

}