Zend Framework教程之Zend_Layout布局助手详解

本文实例讲述了Zend Framework教程之Zend_Layout布局助手。分享给大家供大家参考，具体如下：

一、作用

布局的作用和模版的作用类似。可以认为是把网站通用、公共的部分拿出来作为通用的页面框架。例如一个基本的web页面，可能页面的头和尾都是一样，不一样的可能只是内容body部分不一样，可以把公共的部分做成模版。不仅可以提高开发效率，也为后期的维护带来方便。

二、使用

这里举一个简单的例子。

首先用zend studio创建一个基本的zend framework项目：layout_demo1

结构大概如下“

├─.settings
├─application
│ ├─configs
│ ├─controllers
│ ├─models
│ └─views
│      ├─helpers
│      └─scripts
│          ├─error
│          └─index
├─docs
├─library
├─public
└─tests
    ├─application
    │ └─controllers
    └─library

1.加入layout功能：

应用配置文件/layout_demo2/application/configs/application.ini，加入如下配置

resources.frontController.controllerDirectory = APPLICATION_PATH "/controllers"resources.frontController.params.displayExceptions = 0resources.layout.layoutPath = APPLICATION_PATH "/layouts/scripts/"[staging : production]

2.相应的目录和布局模版文件 /layout_demo2/application/layouts/scripts/layout.phtml

├─application
│ ├─configs
│ ├─controllers
│ ├─layouts
│ │ └─scripts
│ ├─models
│ └─views

layout.html类似如下：

<!doctype html><html> <head>  <meta http-equiv="Content-Type" content="text/html;charset=utf-8">  <title>my app</title>  <body>   <div id="header">    header   </div>   <div id="content">    <?php echo $this -> layout() -> content;?>   </div>   <div id="footer">    header   </div>  </body></html>

这里的

<?php echo $this -> layout() -> content;?>

是比较重要的。表示此处为布局的内容，也就是会动态变化的地方。

这样，运行一下程序

www.localzend.com/layout_demo1/public/

生成的html源码如下

<!doctype html><html> <head>  <meta http-equiv="Content-Type" content="text/html;charset=utf-8">  <title>my app</title>  <body>   <div id="header">    header   </div>   <div id="content">    <style> a:link, a:visited {  color: #0398CA; } span#zf-name {  color: #91BE3F; } div#welcome {  color: #FFFFFF;  background-image: url(http://framework.zend.com/images/bkg_header.jpg);  width: 600px;  height: 400px;  border: 2px solid #444444;  overflow: hidden;  text-align: center; } div#more-information {  background-image: url(http://framework.zend.com/images/bkg_body-bottom.gif);  height: 100%; }</style><div id="welcome"> <h1>Welcome to the <span id="zf-name">Zend Framework!</span></h1> <h3>This is your project's main page</h3> <div id="more-information">  <p><img src="http://framework.zend.com/images/PoweredBy_ZF_4LightBG.png" /></p>  <p>   Helpful Links: <br />   <a href="http://framework.zend.com/">Zend Framework Website</a> |   <a href="http://framework.zend.com/manual/en/">Zend Framework Manual</a>  </p> </div></div>   </div>   <div id="footer">    header   </div>  </body></html>

中间部分就是/layout_demo1/application/views/scripts/index/index.phtml的内容。

注入：可以通过zf的命令工具自动生成layout的配置和文件。

命令如下:

zf enable layout

可以参考命令行章节

三、配置

1.自定义存放位置和名称可以通过application.ini配置文件配置布局文件的存放位置以及布局文件的名称，例如:

resources.layout.layoutPath = APPLICATION_PATH "/mylayouts/scripts"resources.layout.layout = "mylayout"

2.在action中使用layout对象

可以通过

$layout = $this->_helper->layout();

或者

$helper = $this->_helper->getHelper('Layout');$layout = $helper->getLayoutInstance();

获取布局对象。

可以通过如下方式禁用当前action使用布局模式

$layout->disableLayout();

可以通过

$layout->setLayout('other');

来设置使用另一个布局文件

可以通过来传递赋值

$layout->assign('headertitle', 'app title');$layout->somekey = "value"

3.其它获取layout对象的方法

(1)

$layout = Zend_Layout::getMvcInstance();

(2)

$layout = $bootstrap->getResource('Layout');

四、其它用法，实现原理

具体其它的使用方法可以参考

Zend_Layout_Controller_Action_Helper_Layout类，
Zend_Layout_Controller_Plugin_Layout类
Zend_View_Helper_Layout类
不言自明。

<?php/** Zend_Controller_Action_Helper_Abstract */require_once 'Zend/Controller/Action/Helper/Abstract.php';/** * Helper for interacting with Zend_Layout objects * * @uses  Zend_Controller_Action_Helper_Abstract * @category Zend * @package Zend_Controller * @subpackage Zend_Controller_Action * @copyright Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com) * @license http://framework.zend.com/license/new-bsd  New BSD License */class Zend_Layout_Controller_Action_Helper_Layout extends Zend_Controller_Action_Helper_Abstract{ /**  * @var Zend_Controller_Front  */ protected $_frontController; /**  * @var Zend_Layout  */ protected $_layout; /**  * @var bool  */ protected $_isActionControllerSuccessful = false; /**  * Constructor  *  * @param Zend_Layout $layout  * @return void  */ public function __construct(Zend_Layout $layout = null) {  if (null !== $layout) {   $this->setLayoutInstance($layout);  } else {   /**    * @see Zend_Layout    */   require_once 'Zend/Layout.php';   $layout = Zend_Layout::getMvcInstance();  }  if (null !== $layout) {   $pluginClass = $layout->getPluginClass();   $front = $this->getFrontController();   if ($front->hasPlugin($pluginClass)) {    $plugin = $front->getPlugin($pluginClass);    $plugin->setLayoutActionHelper($this);   }  } } public function init() {  $this->_isActionControllerSuccessful = false; } /**  * Get front controller instance  *  * @return Zend_Controller_Front  */ public function getFrontController() {  if (null === $this->_frontController) {   /**    * @see Zend_Controller_Front    */   require_once 'Zend/Controller/Front.php';   $this->_frontController = Zend_Controller_Front::getInstance();  }  return $this->_frontController; } /**  * Get layout object  *  * @return Zend_Layout  */ public function getLayoutInstance() {  if (null === $this->_layout) {   /**    * @see Zend_Layout    */   require_once 'Zend/Layout.php';   if (null === ($this->_layout = Zend_Layout::getMvcInstance())) {    $this->_layout = new Zend_Layout();   }  }  return $this->_layout; } /**  * Set layout object  *  * @param Zend_Layout $layout  * @return Zend_Layout_Controller_Action_Helper_Layout  */ public function setLayoutInstance(Zend_Layout $layout) {  $this->_layout = $layout;  return $this; } /**  * Mark Action Controller (according to this plugin) as Running successfully  *  * @return Zend_Layout_Controller_Action_Helper_Layout  */ public function postDispatch() {  $this->_isActionControllerSuccessful = true;  return $this; } /**  * Did the previous action successfully complete?  *  * @return bool  */ public function isActionControllerSuccessful() {  return $this->_isActionControllerSuccessful; } /**  * Strategy pattern; call object as method  *  * Returns layout object  *  * @return Zend_Layout  */ public function direct() {  return $this->getLayoutInstance(); } /**  * Proxy method calls to layout object  *  * @param string $method  * @param array $args  * @return mixed  */ public function __call($method, $args) {  $layout = $this->getLayoutInstance();  if (method_exists($layout, $method)) {   return call_user_func_array(array($layout, $method), $args);  }  require_once 'Zend/Layout/Exception.php';  throw new Zend_Layout_Exception(sprintf("Invalid method '%s' called on layout action helper", $method)); }}

<?php/** Zend_Controller_Plugin_Abstract */require_once 'Zend/Controller/Plugin/Abstract.php';/** * Render layouts * * @uses  Zend_Controller_Plugin_Abstract * @category Zend * @package Zend_Controller * @subpackage Plugins * @copyright Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com) * @license http://framework.zend.com/license/new-bsd  New BSD License * @version $Id: Layout.php 23775 2011-03-01 17:25:24Z ralph $ */class Zend_Layout_Controller_Plugin_Layout extends Zend_Controller_Plugin_Abstract{ protected $_layoutActionHelper = null; /**  * @var Zend_Layout  */ protected $_layout; /**  * Constructor  *  * @param Zend_Layout $layout  * @return void  */ public function __construct(Zend_Layout $layout = null) {  if (null !== $layout) {   $this->setLayout($layout);  } } /**  * Retrieve layout object  *  * @return Zend_Layout  */ public function getLayout() {  return $this->_layout; } /**  * Set layout object  *  * @param Zend_Layout $layout  * @return Zend_Layout_Controller_Plugin_Layout  */ public function setLayout(Zend_Layout $layout) {  $this->_layout = $layout;  return $this; } /**  * Set layout action helper  *  * @param Zend_Layout_Controller_Action_Helper_Layout $layoutActionHelper  * @return Zend_Layout_Controller_Plugin_Layout  */ public function setLayoutActionHelper(Zend_Layout_Controller_Action_Helper_Layout $layoutActionHelper) {  $this->_layoutActionHelper = $layoutActionHelper;  return $this; } /**  * Retrieve layout action helper  *  * @return Zend_Layout_Controller_Action_Helper_Layout  */ public function getLayoutActionHelper() {  return $this->_layoutActionHelper; } /**  * postDispatch() plugin hook -- render layout  *  * @param Zend_Controller_Request_Abstract $request  * @return void  */ public function postDispatch(Zend_Controller_Request_Abstract $request) {  $layout = $this->getLayout();  $helper = $this->getLayoutActionHelper();  // Return early if forward detected  if (!$request->isDispatched()   || $this->getResponse()->isRedirect()   || ($layout->getMvcSuccessfulActionOnly()    && (!empty($helper) && !$helper->isActionControllerSuccessful())))  {   return;  }  // Return early if layout has been disabled  if (!$layout->isEnabled()) {   return;  }  $response = $this->getResponse();  $content = $response->getBody(true);  $contentKey = $layout->getContentKey();  if (isset($content['default'])) {   $content[$contentKey] = $content['default'];  }  if ('default' != $contentKey) {   unset($content['default']);  }  $layout->assign($content);  $fullContent = null;  $obStartLevel = ob_get_level();  try {   $fullContent = $layout->render();   $response->setBody($fullContent);  } catch (Exception $e) {   while (ob_get_level() > $obStartLevel) {    $fullContent .= ob_get_clean();   }   $request->setParam('layoutFullContent', $fullContent);   $request->setParam('layoutContent', $layout->content);   $response->setBody(null);   throw $e;  } }}

<?php/** Zend_View_Helper_Abstract.php */require_once 'Zend/View/Helper/Abstract.php';/** * View helper for retrieving layout object * * @package Zend_View * @subpackage Helper * @copyright Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com) * @license http://framework.zend.com/license/new-bsd  New BSD License */class Zend_View_Helper_Layout extends Zend_View_Helper_Abstract{ /** @var Zend_Layout */ protected $_layout; /**  * Get layout object  *  * @return Zend_Layout  */ public function getLayout() {  if (null === $this->_layout) {   require_once 'Zend/Layout.php';   $this->_layout = Zend_Layout::getMvcInstance();   if (null === $this->_layout) {    // Implicitly creates layout object    $this->_layout = new Zend_Layout();   }  }  return $this->_layout; } /**  * Set layout object  *  * @param Zend_Layout $layout  * @return Zend_Layout_Controller_Action_Helper_Layout  */ public function setLayout(Zend_Layout $layout) {  $this->_layout = $layout;  return $this; } /**  * Return layout object  *  * Usage: $this->layout()->setLayout('alternate');  *  * @return Zend_Layout  */ public function layout() {  return $this->getLayout(); }}