prestashop模块没有显示在左列和右列？

I am a newbie to the prestashop modules development. Currently I have developed a module. It is working fine in backend (like update and delete inserted values). But when I tried to check the function of the module from frontend it is not showing. My code for install the module is look like this

 public function install()
  {
    if(!parent::install())
      return false;
    if (!$this->registerHook('leftColumn'))
      return false;
    if (!$this->registerHook('header'))
      return false;
    if (!$this->registerHook('rightColumn'))
      return false;
      return true;
   }

The code for the hook is like this

 public function hookHome($params)
  {
    global $cookie, $smarty;
    $value=array();
    .....................
    ............
    return $this->display(__FILE__, 'filename.tpl');
  }

I have tried many methods to show the module in left column and the right column of the page but its not showing there.

But when I tried to transplant the module from admin->modules->positions->transplant a module->hook into->displayHome (Homepage content). it worked in homepage content. But I want to show them in left and right column also. I have tried to use live edit but the module is not showing in left and right column at all. So can someone tell me what is the wrong here? Any help and suggestions will be really appreciable. Thanks.

When you register a hook in your module, you have to define a method to call when the hook is fired. In your case, you have to define the following methods :

public function hookLeftColumn($params)
{
    // Do your stuff on left column
}

public function hookRightColumn($params)
{
    // Do your stuff on right column
}

public function hookHeader($params)
{
    // Do your stuff in the header
}