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 = 0 resources.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();
}
}
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