本文實(shí)例講述了Zend Framework教程之Zend_Layout布局助手。分享給大家供大家參考，具體如下：
一、作用
布局的作用和模版的作用類似。可以認(rèn)為是把網(wǎng)站通用、公共的部分拿出來作為通用的頁面框架。例如一個(gè)基本的web頁面，可能頁面的頭和尾都是一樣，不一樣的可能只是內(nèi)容body部分不一樣，可以把公共的部分做成模版。不僅可以提高開發(fā)效率，也為后期的維護(hù)帶來方便。
二、使用
這里舉一個(gè)簡(jiǎn)單的例子。
首先用zend studio創(chuàng)建一個(gè)基本的zend framework項(xiàng)目：layout_demo1
結(jié)構(gòu)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：
應(yīng)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.相應(yīng)的目錄和布局模版文件 /layout_demo2/application/layouts/scripts/layout.phtml
├─application
│ ├─configs
│ ├─controllers
│ ├─layouts
│ │ └─scripts
│ ├─models
│ └─views
layout.html類似如下：
<!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>
這里的
<?php echo $this -> layout() -> content;?>
是比較重要的。表示此處為布局的內(nèi)容，也就是會(huì)動(dòng)態(tài)變化的地方。
這樣，運(yùn)行一下程序
www.localzend.com/layout_demo1/public/
生成的html源碼如下
<!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> 中間部分就是/layout_demo1/application/views/scripts/index/index.phtml的內(nèi)容。
注入：可以通過zf的命令工具自動(dòng)生成layout的配置和文件。
命令如下:
zf enable layout
可以參考命令行章節(jié)
三、配置
1.自定義存放位置和名稱可以通過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稱，例如:
resources.layout.layoutPath = APPLICATION_PATH "/mylayouts/scripts"resources.layout.layout = "mylayout"
2.在action中使用layout對(duì)象
可以通過
$layout = $this->_helper->layout();
或者
$helper = $this->_helper->getHelper('Layout');$layout = $helper->getLayoutInstance(); 獲取布局對(duì)象。
可以通過如下方式禁用當(dāng)前action使用布局模式
$layout->disableLayout();
可以通過
$layout->setLayout('other'); 來設(shè)置使用另一個(gè)布局文件
可以通過來傳遞賦值
$layout->assign('headertitle', 'app title');$layout->somekey = "value" 3.其它獲取layout對(duì)象的方法
(1)
$layout = Zend_Layout::getMvcInstance();
(2)
$layout = $bootstrap->getResource('Layout'); 四、其它用法，實(shí)現(xiàn)原理
具體其它的使用方法可以參考
Zend_Layout_Controller_Action_Helper_Layout類，
Zend_Layout_Controller_Plugin_Layout類
Zend_View_Helper_Layout類
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(); }} 
