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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