下面我们以Smarty试图引擎为例来如何实现Yaf的视图接口，Yaf_View_Interface。实现接口之前我们先看下Yaf_View_Interface需要实现的所有成员方法
Yaf_View_Interface {/* 方法 */abstract public bool assign ( string $name [, string $value ] )abstract public bool display ( string $tpl [, array $tpl_vars ] )abstract public void getScriptPath ( void )abstract public string render ( string $tpl [, array $tpl_vars ] )abstract public void setScriptPath ( string $template_dir )}//所以我们一定要实现以上5个方法，以下是代码实例_smarty = new Smarty; if (null !== $tmplPath) { $this->setScriptPath($tmplPath); } foreach ($extraParams as $key => $value) { $this->_smarty->$key = $value; } } /** * Set the path to the templates * * @param string $path The directory to set as the path. * @return void */ public function setScriptPath($path) { if (is_readable($path)) { $this->_smarty->template_dir = $path; return; } throw new Exception('Invalid path provided'); } /** * Assign a variable to the template * * @param string $key The variable name. * @param mixed $val The variable value. * @return void */ public function __set($key, $val) { $this->_smarty->assign($key, $val); } /** * Allows testing with empty() and isset() to work * * @param string $key * @return boolean */ public function __isset($key) { return (null !== $this->_smarty->get_template_vars($key)); } /** * Allows unset() on object properties to work * * @param string $key * @return void */ public function __unset($key) { $this->_smarty->clear_assign($key); } /** * Assign variables to the template * * Allows setting a specific key to the specified value, OR passing * an array of key => value pairs to set en masse. * * @see __set() * @param string|array $spec The assignment strategy to use (key or * array of key => value pairs) * @param mixed $value (Optional) If assigning a named variable, * use this as the value. * @return void */ public function assign($spec, $value = null) { if (is_array($spec)) { $this->_smarty->assign($spec); return; } $this->_smarty->assign($spec, $value); } /** * Clear all assigned variables * * Clears all variables assigned to Yaf_View either via * {@link assign()} or property overloading * ({@link __get()}/{@link __set()}). * * @return void */ public function clearVars() { $this->_smarty->clear_all_assign(); } /** * Processes a template and returns the output. * * @param string $name The template to process. * @return string The output. */ public function render($name, $value = NULL) { return $this->_smarty->fetch($name); } public function display($name, $value = NULL) { echo $this->_smarty->fetch($name); }}?>//实现之后我们可以在Bootstrap中注册我们的smarty模板引擎了getConfig(); Yaf_Registry::set("config", $config); } public function _initLocalName() { /** 将Smarty_Adapter注册为本地类哭 */ Yaf_Loader::getInstance()->registerLocalNamespace('Smarty'); } public function _initSmarty(Yaf_Dispatcher $dispatcher) { $smarty = new Smarty_Adapter(null, Yaf_Registry::get("config")->get("smarty")); $dispatcher->setView($smarty); /* 设置smarty为我们的模板引擎 */ }}?>