The widgets of the Yii framework are using a so called 'dataprovider'. They support the order of the data by any attribute but in some cases we need a default order. To achive this we need to set the 'defaultOrder' property of the 'sort' property(which is a CSort class) of the dataProvider:

$dataProvider=new CActiveDataProvider('Post', array(
	    'criteria'=>array(
	        'condition'=>'status=1',
	        'with'=>array('author'),
	    ),
		'sort' => array(
			'defaultOrder' => 'create_time DESC'
		),
	    'pagination'=>array(
	        'pageSize'=>20,
	    ),
	));