Make Buttons Visible or Not visible according to permissions Given

<?php
$user_id=Yii::app()->user->id;
$AuthAssignments = AuthAssignment::model() -> findAll(array("condition"=>"userid = $user_id","order"=>"itemname"));

$Authitemchildren = Authitemchild::model() -> findAll();
$visibleView = 'false;';
$visibleEdit = 'false;';
$visibleDelete = 'false;';
foreach($Authitemchildren as $Authitemchild){
foreach($AuthAssignments as $AuthAssignment){
if($Authitemchild['parent']==$AuthAssignment['itemname'] && $Authitemchild['child']=='MainMenu.View'){
$visibleView = 'true;';
}else if($Authitemchild['parent']==$AuthAssignment['itemname'] && $Authitemchild['child']=='MainMenu.Update'){
$visibleEdit = 'true;';
}
else if($Authitemchild['parent']==$AuthAssignment['itemname'] && $Authitemchild['child']=='MainMenu.Delete'){
$visibleDelete = 'true;';
}
}
}

In buttons

array(

'class'=>'bootstrap.widgets.TbButtonColumn',

'template'=>'{View}{Edit}{Delete}',

'buttons'=>array

(

 

'View' => array

(

'label'=>'View',

'visible' => $visibleView,

'url'=>'Yii::app()->createUrl("MainMenu/view", array("id"=>$data->id))',

'imageUrl' => Yii::app()->baseUrl . '/images/icon/viewicon.jpg',

'options'=>array(

'style'=>'width:130px;height:130px;',

//   'class'=>'btn btn-small btn-info',

),

),

),),