CakePHP布局没有变化

I am working in CakePHP 2.3.0, I developed app using default layout. Now I need to change the layout to design.ctp but the app is rendering default.ctp

    public function myfun() {
      $this -> layout = 'design';

    }

I tried to clear the cache and switched ON the debug mode but the app is still picking the default.ctp

In your controller

class MyTestController extends AppController {
    var $layout = 'default'; 

and in your action try

public function myfun() {
  $this->layout = 'design';
}

Now, your view will use design.ctp, which is stored in views/layouts/.

$this->layout = false; comment above line and it will work fine if you are palcing your lay