/*适用情况：比如提交一个表单，提交完成之后在页面展示一条提示消息。

 控制器里面这样写：

 单条消息：

 */

 \Yii::$app->getSession()->setFlash('error', 'This is the message');

 \Yii::$app->getSession()->setFlash('success', 'This is the message');

 \Yii::$app->getSession()->setFlash('info', 'This is the message');

 #多条消息：

 \Yii::$app->getSession()->setFlash('error', ['Error 1', 'Error 2']);

 #然后是视图里面：

 先引入Alert：use yii\bootstrap\Alert;

 if( Yii::$app->getSession()->hasFlash('success') ) {

     echo Alert::widget([

         'options' => [

             'class' => 'alert-success', //这里是提示框的class

         ],

         'body' => Yii::$app->getSession()->getFlash('success'), //消息体

     ]);

 }

 if( Yii::$app->getSession()->hasFlash('error') ) {

     echo Alert::widget([

         'options' => [

             'class' => 'alert-error',

         ],

         'body' => Yii::$app->getSession()->getFlash('error'),

     ]);

 }

 //c控制器里面这样写 CompanyInfoController

 //公司信息

     public function actionIndex()

     {

         $result = CompanyService::CompanyInfo();

         $types = Yii::$app->params['companyType'];

         $model = CompanyInfo::find()->where(['id' =>Yii::$app->company->getId()])->one();

         if (Yii::$app->request->post() && CompanyService::UpdateConpanyInfo(Yii::$app->request->post())) {

             Yii::$app->session->setFlash('flag', 'success');

             return $this->redirect('/system/company-info/index');

         }

         return $this->render('index', [

             'staffNum' => $result['staffNum'],

             'model' => $model,

             'type' => $types,

             'businessList' => $result['businessList'],

             'businessParentId' => $result['businessParentId'],

             'sonBusInessList' => $result['sonBusInessList']

         ]);

     }

 //视图里面 index.php

 <script type="text/javascript">

         //消息提示start

         <?php $flag = Yii::$app->session->getFlash('flag');if($flag == 'success'): ?>

         layer.msg('公司信息更新成功');

         <?php endif; ?>

         //消息提示end

 </script>