Zend Framework call view helper from a Zend_View_Helper

Question

I have a helper called Zend_View_Helper_FormVars that's used by one of my modules. I also have a common helper in application/common/helpers/GeneralFunctions.php

I'm trying to call a function from Zend_View_Helper_FormVars that's in GeneralFunctions.php

Here is the sort version of Zend_View_Helper_FormVars

class Zend_View_Helper_FormVars
{
    public $reqFieldVisual='<span class="req">*</span>';
    public $roles=array('admin'=>'admin', 'user'=>'user');
    public $paymentMethods=array('1'=>'Check', '2'=>'Credit Card',
                '3'=>'Cash', '4'=>'Other');


    public function formVars(){
        $this->baseUrl=Zend_Controller_Front::getInstance()->getBaseUrl();
        return $this;
    }

    public function mkCategoryCodeSelectGroup($codeTypeArr=array(),
        $codesArr=array()) {
        $html='';
        $html.=Zend_View_Helper_GeneralFunctions::generalFunctions()->progressMeter();
        return $html;
    }
}

Here is the code in GeneralFunctions.php

class Zend_View_Helper_GeneralFunctions
{
    public function generalFunctions(){
        $this->baseUrl=Zend_Controller_Front::getInstance()->getBaseUrl();
        return $this;   
    }

    public function progressMeter() {
        $html='';
        $html.='<span id="progressWrapper">';
        $html.='<span id="progressMeter"></span>';
        $html.='</span>';
        $html.='';
        return $html;
    }
}

Also, forgot to mention, that I have the GeneralFunctions helper auto loaded in the Bootstrap like this and it's available to all my modules already:

$view->addHelperPath(APPLICATION_PATH .'/common/helpers', 'View_Helper');

Answer 1

You possibly haven't configured your autoloader to load classes from the application/common/helpers/ folder.

See Zend_Application_Module_Autoloader for default paths. You should add your new folder to this.

Answer 2

You are calling your class without instantiating it.

Your generalFunctions() function uses the $this pointer which won't work, also it isn't a static method.

One option is set progress meter to be a static function and call it directly like this:

Zend_View_Helper_GeneralFunctions::progressMeter();

Another option is to instantiate your class first.

Answer 3

I see several problems with your provided code.

1. You are attempting to call Zend_View_Helper_GeneralFunctions::generalFunctions() as a static method when it is declared as a class method (ie you have to instantiate an instance of the class to use it) by reason of your omission of the 'static' keyword.
2. If you in fact want to use generalFunctions() as a static method and correct this then you will need to either make baseUrl a static property or you will have to instantiate an instance of the class and then return that instance.
3. The idea of using your GeneralFunctions class as a container for static methods that are called directly is really a symptom of deeper problems and is rightly labeled a code smell. If you think that I'm lying take a look at the high priority items for the Zend Framework 2.0 (hint: it involves removing all static methods from the framework). Or you can always ask SO what they think of static methods :-).

Looking at your given class name for the general functions class "Zend_View_Helper_GeneralFunctions" and given the current scenario where you are trying to use the GeneralFunctions helper inside another helper, I would surmise that you really need to do one of two things.

1. You need to have every helper class subclass the GeneralFunctions class so that all of your helpers have these functions available. Basically, ask yourself if your helpers all start out life as GeneralFunction helpers with extended functionality beyond. This solution uses inheritance to solve your problem.

2. Every view helper should contain an instance of the View object being acted upon. Therefore in theory you should be able to access any other view helper via the magic __call method (I think there is also an explicit method but I always use the magic method). It mike look like so in your scenario:

   public function mkCategoryCodeSelectGroup($codeTypeArr=array(), $codesArr=array()) { $html=''; $html.= $this->generalFunctions()->progressMeter(); return $html; }

In this scenario the __call method would load the GeneralFunctions helper and would then would call the progressMeter() method from the GeneralFunctions helper.

Now your GeneralFunctions helper class would probably look like this:

class Zend_View_Helper_GeneralFunctions
{
    public function __construct()
    {
        $this->baseUrl = Zend_Controller_Front::getInstance()->getBaseUrl();
    }

    public function progressMeter() {
        $html='';
        $html.='<span id="progressWrapper">';
        $html.='<span id="progressMeter"></span>';
        $html.='</span>';
        $html.='';
        return $html;
    }
}

Answer 4

It's actually really simple to call another View Helper.

Make sure that your view helper extends Zend_View_Helper_Abstract, so that it has access to the $view. Then you may simply call helpers as you would from a view, i.e.

$this->view->generalFunctions()->progressMeter();

Based on your example above:

<?php

class Zend_View_Helper_FormVars extends Zend_View_Helper_Abstract {

    /* ... */

    public function mkCategoryCodeSelectGroup($codeTypeArr=array(),
        $codesArr=array()) {
        $html='';
        $html. $this->view->generalFunctions()->progressMeter();
        return $html;
    }
}

Answer 5

Here is what I tried, but am getting an error:

// application/Bootstrap.php ----------->
function _initViewHelpers() {
    // add a helper for use for all modules
    $view->addHelperPath(APPLICATION_PATH .'/Common/Helper', 'Common_Helper');
}
//-------------------->


// application/common/helpers/General.php ----------->
class Zend_View_Helper_General extends Zend_View_Helper_Abstract
{
    public function general(){
     return $this;
    } 
    public function test(){
     return 'test 123';
    }
}
//-------------------->

// application/modules/dashboard/views/helpers/DashboardHelper.php ----------->
class Zend_View_Helper_DashboardHelper extends Common_Helper_General
{

    public function dashboardHelper(){
     return $this;
    }

    public function dashboardTest(){
     return 'from dashboard';
    }

}
//-------------------->

// application/modules/dashboard/views/scripts/index/index.phtml ----------->
echo $this->dashboardHelper()->test();
//-------------------->

Error message I get: Fatal error: Class 'Common_Helper_General' not found in /Applications/MAMP/htdocs/mysite/application/modules/dashboard/views/helpers/DashboardHelper.php on line 2