Yii 设置 flash消息 创建一个渐隐形式的消息框

 /*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'),
     ]);
 }

项目代码示例：

 //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>