Usage without DB I/O + Polymorphism

ATK Howto: Usage without DB I/O + Polymorphism

Complexity: Easy
Author: BERT

Intro

If you want to use the power of any attribute without having database I/O involved either in a normal node or maybe in the admin screen, like what the dummy attribute does. This how to will help you with that.

Creating a custom attribute without I/O

Create your attribute by extending the one you desire. In this case I'm extending the list or 'dropdown box'. You then need to change the loadType and storeType to return a value of 0 so it doesn't interface with the database.

useattrib("atklistattribute");
class listNoIO extends atkListAttribute
{
   function listNoIO($name, $optionArray, $valueArray="", $flags=0, $size=0  )
   {
       $this->atkListAttribute($name, $optionArray, $valueArray, $flags, $size );
       // this attribute will only be visible in edit screens:
       $this->addFlag(AF_HIDE); $this->removeFlag(AF_HIDE_ADD);
   }
   function loadType()
  {
   // this makes sure this attribute does not partake in the query that loads
   // data. Since we aren't a real relationship, we don't have anything to load.
   return 0;
  } 
   function storageType()
   {
      return 0;
   }
}

Using that attribute in your node

Add it to your node. Upon Saving via the Edit or Add the $record will contain these values and can be used in places like validate or postUpdate

 useattrib("yourmodule.listnoio");

 class yournode extends atkNode {
   function yournode () {
    $attr = &$this->add(new listNoIO( "adminview",
                              array( "All","Not_All") ,
                              array( "A","N"), AF_LIST_NO_NULL_ITEM ));
 }

 function postUpdate(&$record) 
     {     
     if ( $record['adminview'] == 'N' ) {
        $this->doSomethingSpecial( $record );
     }
     return true;
   }  
 }

Using it to polymorphism your admin list

Lets put this list attribute in the Header area and use it to change our columns.

 useattrib("yourmodule.listnoio");

 class yournode extends atkNode {
   function yournode () {
    GLOBAL $ATK_VARS;
    // change it to always be hidden
    $attr = &$this->add(new listNoIO( "adminview",
                              array( "All","Not_All") ,
                              array( "A","N"), AF_HIDE|AF_LIST_NO_NULL_ITEM ));

      // make it happen 'onChange' of the value and pass it back the one selected
      $attr->addOnChangeHandler( " window.location='".str_replace("'","\'",$_SERVER['REQUEST_URI'])."&chgadminview='+newvalue;");
        
      // See if we already have an adminview value set        
      $session = &atkSessionManager::getSession();
      $adminView = $session['adminview'];
  
      // check to see if our adminview dropdown was changed
      if ( isset( $ATK_VARS['chgadminview'])){      
           $adminView = $ATK_VARS['chgadminview'] ;           
           // save our admin value on our session stack so we can reference it when we
           // come back to the admin screen
           $session['adminview'] = $adminView;    
      }             
      
      if ( isset($adminView) && $ATK_VARS['atkaction'] == 'admin' ) {   
          $attr->setSelected( $adminView );   // set the selected one as default
           if    ( $adminView == 'N' ) {
               // lets say we have 2 attributes which are normally not on the 
               // admin screen and we want to put them there
              foreach ( array('Attr1','Attr2') as $var ) {
                $attr = &$this->getAttribute( $var );
                $attr->removeFlag( AF_HIDE_LIST );
              }
               
           } 
 }

 // put the attribute in the Header area
 function adminHeader(){
       // setup adminview list box for viewing just finals or final 4   
       $attr=&$this->getAttribute("adminview");              
       // please note: $rec is blank here
       $help_text =  '<tr><td align="left">'."VIEW: ".$attr->edit( $rec, 'edit') . '</td></tr>';
   return $help_text;
 }
}