joomla/view

Joomla View Package

The View Package

, _(*1)

Interfaces

View\ViewInterface

View\ViewInterface is an interface that requires a class to be implemented with an escape and a render method., _(*2)

Classes

View\AbstractView

Construction

The contructor for View\AbstractView takes a mandatory Model\ModelInterface parameter., _(*3)

Note that Model\ModelInterface is an interface so the actual object passed does necessarily have to extend from Model\AbstractModel class. Given that, the view should only rely on the API that is exposed by the interface and not concrete classes unless the constructor is changed in a derived class to take more explicit classes or interfaces as required by the developer., _(*4)

Usage

The View\AbstractView class is abstract so cannot be used directly. It forms a simple base for rendering any kind of data. The class already implements the escape method so only a render method need to be added. Views derived from this class would be used to support very simple cases, well suited to supporting web services returning JSON, XML or possibly binary data types. This class does not support layouts., _(*5)

namespace myApp;

use Joomla\View\AbstractView;

/**
 * My custom view.
 *
 * @package  Examples
 *
 * @since   1.0
 */
class MyView extends AbstractView
{
    /**
     * Render some data
     *
     * @return  string  The rendered view.
     *
     * @since   1.0
     * @throws  \RuntimeException on database error.
     */
    public function render()
    {
        // Prepare some data from the model.
        $data = array('count' => $this->model->getCount());

        // Convert the data to JSON format.
        return json_encode($data);
    }
}

try
{
    $view = new MyView(new MyDatabaseModel());
    echo $view->render();
}
catch (RuntimeException $e)
{
    // Handle database error.
}

View\AbstractHtmlView

Construction

View\AbstractHtmlView is extended from View\AbstractView. The constructor, in addition to the required model argument, take an optional SplPriorityQueue object that serves as a lookup for layouts. If omitted, the view defers to the protected loadPaths method., _(*6)

Usage

The View\AbstractHtmlView class is abstract so cannot be used directly. This view class implements render. It will try to find the layout, include it using output buffering and return the result. The following examples show a layout file that is assumed to be stored in a generic layout folder not stored under the web-server root., _(*7)

namespace myApp;

use Joomla\View;

// Declare variables to support type hinting.

/** @var $this MyHtmlView */
?>

Count

model->getCount(); ?>

namespace myApp;

use Joomla\View;

/**
 * My custom HTML view.
 *
 * @package  Examples
 * @since    1.0
 */
class MyHtmlView extends View\AbstractHtmlView
{
    /**
     * Redefine the model so the correct type hinting is available in the layout.
     *
     * @var     MyDatabaseModel
     * @since   1.0
     */
    protected $model;
}

try
{
    $paths = new \SplPriorityQueue;
    $paths->insert(__DIR__ . '/layouts');

    $view = new MyView(new MyDatabaseModel, $paths);
    $view->setLayout('count');
    echo $view->render();

    // Alternative approach.
    $view = new MyView(new MyDatabaseModel);

    // Use some chaining.
    $view->setPaths($paths)->setLayout('count');

    // Take advantage of the magic __toString method.
    echo $view;
}
catch (RuntimeException $e)
{
    // Handle database error.
}

The default extension for layouts is ".php". This can be modified in derived views by changing the default value for the extension argument. For example:, _(*8)

namespace myApp;

use Joomla\View;

/**
 * My custom HTML view.
 *
 * @package  Examples
 * @since    1.0
 */
class MyHtmlView extends View\AbstractHtmlView
{
    /**
     * Override the parent method to use the '.phtml' extension for layout files.
     *
     * @param   string  $layout  The base name of the layout file (excluding extension).
     * @param   string  $ext     The extension of the layout file (default: "phtml").
     *
     * @return  mixed  The layout file name if found, false otherwise.
     *
     * @see     View\AbstractHtmlView::getPath
     * @since   1.0
     */
    public function getPath($layout, $ext = 'phtml')
    {
        return parent::getPath($layout, $ext);
    }
}

Installation via Composer

Add "joomla/view": "~1.0" to the require block in your composer.json and then run composer install., _(*9)

{
    "require": {
        "joomla/view": "~1.0"
    }
}

Alternatively, you can simply run the following from the command line:, _(*10)

composer require joomla/view "~1.0"