update

resources/views/grid/table.blade.php

@@ -32,7 +32,7 @@
     <div class="card-body panel-collapse collapse in table-responsive" {!! $grid->option('show_bordered') ? 'style="padding:3px 10px 10px"' : '' !!}>
         <table class=" table table-hover responsive {{ $grid->option('show_bordered') ? 'table-bordered' : $grid->option('table_header_style') }} " id="{{$tableId}}">
             <thead>
-            @if ($headers = $grid->getMultipleHeaders())
+            @if ($headers = $grid->multipleHeaders())
                 <tr>
                     @foreach($headers as $header)
                         {!! $header->render() !!}

src/Grid.php

@@ -29,7 +29,7 @@ class Grid
         Concerns\HasActions,
         Concerns\HasPaginator,
         Concerns\HasExporter,
-        Concerns\HasMultipleHeader,
+        Concerns\HasMultipleHeaders,
         Concerns\HasQuickSearch,
         Concerns\HasSelector,
         Macroable {

src/Grid/Concerns/HasMultipleHeader.php → src/Grid/Concerns/HasMultipleHeaders.php

@@ -3,14 +3,14 @@
 namespace Dcat\Admin\Grid\Concerns;
 
 use Dcat\Admin\Grid\Column;
-use Dcat\Admin\Grid\Header;
+use Dcat\Admin\Grid\FirstRowHeader;
 
-trait HasMultipleHeader
+trait HasMultipleHeaders
 {
     /**
      * Table multiple headers.
      *
-     * @var Header[]
+     * @var FirstRowHeader[]
      */
     protected $multipleHeaders = [];
 
@@ -20,23 +20,23 @@ trait HasMultipleHeader
      * @param string $label
      * @param array  $columnNames
      *
-     * @return Header
+     * @return FirstRowHeader
      */
     public function combine(string $label, array $columnNames)
     {
         if (count($columnNames) < 2) {
-            throw new \InvalidArgumentException('The number of "$columnNames" must be greater than 2');
+            throw new \InvalidArgumentException('Invalid column names.');
         }
 
         $this->withBorder();
 
-        return $this->multipleHeaders[$label] = new Header($this, $label, $columnNames);
+        return $this->multipleHeaders[$label] = new FirstRowHeader($this, $label, $columnNames);
     }
 
     /**
-     * @return Header[]
+     * @return FirstRowHeader[]
      */
-    public function getMultipleHeaders()
+    public function multipleHeaders()
     {
         return $this->multipleHeaders;
     }
@@ -103,7 +103,7 @@ trait HasMultipleHeader
 
         /* @var Column $column */
         foreach ($columns as $name => $column) {
-            $header = new Header($this, $column->getLabel(), [$name]);
+            $header = new FirstRowHeader($this, $column->getLabel(), [$name]);
             $prio = $column->getDataPriority();
 
             if (is_int($prio)) {

src/Grid/Header.php → src/Grid/FirstRowHeader.php

@@ -6,7 +6,7 @@ use Dcat\Admin\Grid;
 use Dcat\Admin\Grid\Column\Help;
 use Dcat\Admin\Widgets\Widget;
 
-class Header extends Widget
+class FirstRowHeader extends Widget
 {
     /**
      * @var Grid
@@ -96,8 +96,6 @@ class Header extends Widget
     }
 
     /**
-     * Add a help tooltip to column header.
-     *
      * @param string|\Closure $message
      * @param null|string     $style     'green', 'blue', 'red', 'purple'
      * @param null|string     $placement 'bottom', 'left', 'right', 'top'