1.7 HelloWorld 添加视图

模型： 管理数据

控制器：执行任务，设置或者获取模型的状态，请求视图显示

视图：显示被控件选中的内容

（1）Setting the controller

JController是一个管理控制器的类, 在site/helloworld.php添加如下代码。

<?php// No direct access to this file
defined(‘_JEXEC‘) or die(‘Restricted access‘);

// import joomla controller library
jimport(‘joomla.application.component.controller‘);

// Get an instance of the controller prefixed by HelloWorld
$controller= JControllerLegacy::getInstance(‘HelloWorld‘);

// Perform the Request task
$input= JFactory::getApplication()->input;
$controller->execute($input->getCmd(‘task‘)); 

// Redirect if set by the controlle
r$controller->redirect();

JControllerLegacy::getInstance(‘HelloWorld‘);(注意3.x版本使用的是JControllerLegacy，如果看官网上使用的是JController)
创建一个名为HelloWorldController的控制器类，Joomla将会在controller.php中查找这个类的声明。
 
所以在site/controller.php文件中写入下面代码：


<?php
// No direct access to this file
defined(‘_JEXEC‘) or die(‘Restricted access‘);

// import Joomla controller library
jimport(‘joomla.application.component.controller‘);

/**
 * Hello World Component Controller
 */
class HelloWorldController extends JControllerLegacy (注意3.x要继承JControllerLegacy)
{}

当没有指定task的值时，默认task将会被执行，默认task任务是display，所以在HelloWorldController中创建display方法。

（2）Setting the view

当JController想去展示一个view的时候，他将会从目录component/com_helloworld/views/helloworld/目录下查找

site/views/helloworld/view.html.php

<?php
// No direct access to this file
defined(‘_JEXEC‘) or die(‘Restricted access‘);

// import Joomla view library
jimport(‘joomla.application.component.view‘);

/**
 * HTML View class for the HelloWorld Component
 */
class HelloWorldViewHelloWorld  extendsJViewLegacy(注意3.x要继承JViewLegacy){
    // Overwriting JView display method
    function display($tpl=null){
    // Assign data to the view
    $this->msg=‘Hello World‘;

    // Display the view
    parent::display($tpl);
}}

JView类的display方法会被JController类的task方法调用，在这个例子中display方法将会显示tmpl/default.php文件。
 
 
site/views/helloworld/tmpl/default.php

<?php
// No direct access to this file
defined(‘_JEXEC‘) or die(‘Restricted access‘);
?>
<h1><?phpecho$this->msg;?></h1>

这个模板文件将会被JView类包含，所以$this指的是HelloWorldViewHelloWorld类。
 
 
helloworld.xml

<?xmlversion="1.0"encoding="utf-8"?>
<extension type="component"version="2.5.0"method="upgrade">
<name>Hello World!</name>
<!-- The following elements are optional and free of formatting constraints -->
<creationDate>November 2009</creationDate>
<author>John Doe</author>
<authorEmail>[email protected]</authorEmail>
<authorUrl>http://www.example.org</authorUrl>
<copyright>Copyright Info</copyright>
<license>License Info</license>
<!--  The version string is recorded in the components table -->
<version>0.0.2</version>
<!-- The description is optional and defaults to the name -->
<description>Description of the Hello World component ...</description>
<update>
<!-- Runs on update; New in 2.5 -->
<schemas><schemapathtype="mysql">sql/updates/mysql</schemapath></schemas>
</update>

<!-- Site Main File Copy Section --><!-- Note the folder attribute: This attribute describes the folder to copy FROM in the package to install therefore files copied        in this section are copied from /site/ in the package -->
<filesfolder="site"><filename>index.html</filename>
<filename>helloworld.php</filename>
<filename>controller.php</filename>
<folder>views</folder>
</files>

<administration>
    <!-- Administration Menu Section -->
    <menu>Hello World!</menu>
    <!-- Administration Main File Copy Section --><!-- Note the folder attribute: This attribute describes the folder            to copy FROM in the package to install therefore files copied            in this section are copied from /admin/ in the package -->
    <filesfolder="admin">
        <!-- Admin Main File Copy Section -->
        <filename>index.html</filename>
        <filename>helloworld.php</filename>
        <!-- SQL files section -->
        <folder>sql</folder>
    </files>
</administration>

</extension>