yii2阅读随笔14

继续来看Event.php

 /*** Triggers a class-level event.* 触发类级别事件。* This method will cause invocation of event handlers that are attached to the named event* for the specified class and all its parent classes.* 触发某个类或者对象的某个事件* @param string|object $class the object or the fully qualified class name specifying the class-level event.* @param string $name the event name.* @param Event $event the event parameter. If not set, a default [[Event]] object will be created.*/public static function trigger($class, $name, $event = null){if (empty(self::$_events[$name])) {return;}if ($event === null) {// 事件不存在，就创建一个 Event 对象$event = new static;}// 设置event对象的属性，默认是未被处理的$event->handled = false;$event->name = $name;if (is_object($class)) {if ($event->sender === null) {// 如果 $class 是个对象，并且是 sender 为空，就将 $class 赋给 sender，即 $class 就是触发事件的对象$event->sender = $class;}$class = get_class($class);} else {$class = ltrim($class, '\\');}// 循环类的 $_event，直到遇到 $event->handled 为真或者没有父类了为止do {if (!empty(self::$_events[$name][$class])) {foreach (self::$_events[$name][$class] as $handler) {// 将参数赋到 event 对象的 data 属性上$event->data = $handler[1];// 调用 $handler 方法// 在方法中，可以用 $this->data 取到相应的参数// 也可以在其中设置 $this->handled 的值，中断后续事件的触发call_user_func($handler[0], $event);// 当某个 handled 被设置为 true 时，执行到这个事件的时候，会停止，并忽略剩下的事件if ($event->handled) {return;}}}} while (($class = get_parent_class($class)) !== false);}
}Component.php少分析了几个方法，现在添加上去！/*** Detaches an existing event handler from this component.* 在该组件中，将现有的事件处理，* This method is the opposite of [[on()]].* 这种方法与on[]方法相反。* @param string $name event name* @param callable $handler the event handler to be removed.* If it is null, all handlers attached to the named event will be removed.* @return boolean if a handler is found and detached* @see on()*/public function off($name, $handler = null){// 保证 behaviors 都加载进来了$this->ensureBehaviors();// 相应的事件不存在，就返回falseif (empty($this->_events[$name])) {return false;}// 没有handler，就意味着要全部去掉if ($handler === null) {unset($this->_events[$name]);return true;} else {$removed = false;//如果$handler不为空。foreach ($this->_events[$name] as $i => $event) {// $event[0]是handler，$event[1]是数据if ($event[0] === $handler) {unset($this->_events[$name][$i]);$removed = true;}}if ($removed) {// 如果有移出事件的handler，就需要重新构建以下索引，否则会出现index为1,3,4的情况$this->_events[$name] = array_values($this->_events[$name]);}return $removed;}}/*** Triggers an event.* 触发一个事件。* This method represents the happening of an event. It invokes* all attached handlers for the event including class-level handlers.* 这种方法代表事件的发生。它调用的事件包括类级别的处理程序所包含的所有附加处理程序。* @param string $name the event name* @param Event $event the event parameter. If not set, a default [[Event]] object will be created.*/public function trigger($name, Event $event = null){// 保证 behaviors 都加载进来了$this->ensureBehaviors();if (!empty($this->_events[$name])) {// 构建Event对象，为传入到handler函数中做准备if ($event === null) {$event = new Event;}if ($event->sender === null) { //如果$event->sender值为null的话，把$this赋值给它。$event->sender = $this;}$event->handled = false; //使handled值为空$event->name = $name;foreach ($this->_events[$name] as $handler) {// 给event的data属性赋值$event->data = $handler[1];// handler的函数中传入了一个Event对象call_user_func($handler[0], $event);// stop further handling if the event is handled// 事件是否被handle，当handled被设置为true时，执行到这个event的时候，会停止，并忽略剩下的eventif ($event->handled) {return;}}}// invoke class-level attached handlers// 触发class级别的handlerEvent::trigger($this, $name, $event);}