class Event 
{ 
    protected static $listens       = array(); 

    public static function listen($event, $callback, $once=false){ 
        if(!is_callable($callback)) return false; 
        self::$listens[$event][]    = array('callback'=>$callback, 'once'=>$once); 
        return true; 
    } 

    public static function one($event, $callback){ 
        return self::listen($event, $callback, true); 
    } 

    public static function remove($event, $index=null){ 
        if(is_null($index)) 
            unset(self::$listens[$event]); 
        else
            unset(self::$listens[$event][$index]); 
    } 

    public static function trigger(){ 
        if(!func_num_args()) return; 
        $args                       = func_get_args(); 
        $event                      = array_shift($args); 
        if(!isset(self::$listens[$event])) return false; 
        foreach((array) self::$listens[$event] as $index=>$listen){ 
            $callback               = $listen['callback']; 
            $listen['once'] && self::remove($event, $index); 
            call_user_func_array($callback, $args); 
        } 
    } 
}

以下是一些調(diào)用的例子：

復(fù)制代碼代碼如下:

// 增加監(jiān)聽walk事件 
Event::listen('walk', function(){ 
    echo "I am walking...n"; 
}); 
// 增加監(jiān)聽walk一次性事件 
Event::listen('walk', function(){ 
    echo "I am listening...n"; 
}, true); 
// 觸發(fā)walk事件 
Event::trigger('walk'); 
/* 
I am walking... 
I am listening... 
*/
Event::trigger('walk'); 
/* 
I am walking... 
*/

Event::one('say', function($name=''){ 
    echo "I am {$name}n"; 
}); 

Event::trigger('say', 'deeka'); // 輸出 I am deeka 
Event::trigger('say', 'deeka'); // not run 

class Foo 
{ 
    public function bar(){ 
        echo "Foo::bar() is calledn"; 
    } 

    public function test(){ 
        echo "Foo::foo() is called, agrs:".json_encode(func_get_args())."n"; 
    } 
} 

$foo    = new Foo; 

Event::listen('bar', array($foo, 'bar')); 
Event::trigger('bar'); 

Event::listen('test', array($foo, 'test')); 
Event::trigger('test', 1, 2, 3); 

class Bar 
{ 
    public static function foo(){ 
        echo "Bar::foo() is calledn"; 
    } 
} 

Event::listen('bar1', array('Bar', 'foo')); 
Event::trigger('bar1'); 

Event::listen('bar2', 'Bar::foo'); 
Event::trigger('bar2'); 

function bar(){ 
    echo "bar() is calledn"; 
} 

Event::listen('bar3', 'bar'); 
Event::trigger('bar3');
 