index.php

<?php //dist/views/tree/index.php

?>
<br>
<br>
<br>

<?=\app\ext\tree\TreeView::widget([
    'query' => \app\ext\tree\Node::find()->addOrderBy('root, lft'),
    'headingOptions' => ['label' => 'Categories'],
    'rootOptions' => ['label'=>'<span class="text-primary">Root</span>'],
    'fontAwesome' => false
,    'isAdmin' => true,
    'displayValue' => 1,
//    'iconEditSettings'=> [
//        'show' => 'list',
//        'listData' => [
//            'folder' => 'Folder',
//            'file' => 'File',
//            'mobile' => 'Phone',
//            'bell' => 'Bell',
//        ]
//    ],
    'softDelete' => true,
    'cacheSettings' => ['enableCache' => FALSE]
]);

Node.php

<?php //ext/tree/Node.php
namespace app\ext\tree;

use Yii;

class Node extends \kartik\tree\models\Tree
{
    public static function tableName() {
        return 'tbl_tree';
    }

    public function afterSave($isInsert, $changedAttributes) {
        Yii::$app->session['tvScrollTop'] = Yii::$app->request->post('tvScrollTop');

        parent::afterSave($isInsert, $changedAttributes);
    }
}

tree.js

//ext/tree/assets/tree.js
!(function(__tvId) {
   var __tv = window[$('#' + __tvId).data('krajee-treeview')],
    $tree = $('#' + __tv.treeId),
    $detail = $('#' + __tv.detailId),
    $btnCut = $('#' + __tv.toolbarId).find('.kv-cut');

  __tv.alertFadeDuration = 2000

  // cut button
  $btnCut.on('click', function() {
      this.disabled = true
      $(this).data('clipNode', $('#' + __tvId).data('clipNode'))

      // remove tooltip
      this.nextSibling && this.nextSibling.remove()
      showAlert('Select folder to paste')
  })

  $('#' + __tvId).on('treeview.beforeselect',
    function(event, key, jqXHR, settings) {
      this.dataset.clipNode = key

      if ($btnCut.data('clipNode') > 0) {
        move($btnCut.data('clipNode'), key)
        $btnCut.data('clipNode', null)
      }
  })

  $('#'+ __tvId).on('treeview.selected', function(event, key, jqXHR, settings) {
      var $form = $('#' + __tvId + '-nodeform')
      var scrollTop = $tree.scrollTop()
      $form.prepend('<input name=tvScrollTop value='+ scrollTop +' type=hidden>')
      $('#'+ __tv.detailId +' .alert').css('display', 'none').removeClass('hide')
  })

  function move(from, to) {
    var $nodeFrom = $tree.find('li[data-key=' + from + ']'),
      $nodeTo = $tree.find('li[data-key=' + to + ']'),
      dir = 'any'
    $.ajax({
      type: 'post',
      dataType: 'json',
      data: {
        'idFrom': $nodeFrom.data('key'),
        'idTo': $nodeTo.data('key'),
        'modelClass': 'app\\\\ext\\\\tree\\\\Node',
        'dir': dir,
        'allowNewRoots': 1,
        'treeMoveHash': $('input[name=treeMoveHash]').val(),
        'tvScrollTop': $tree.scrollTop()
      },
      url: $('#'+ __tvId).data('moveAction'),
      beforeSend: function(jqXHR, settings) {
        $tree.parent().addClass('kv-loading-search');
      },
      success: function(data, textStatus, jqXHR) {
        if (data.status === 'success') {
          if ($nodeTo.find('li').length > 0) {
            $nodeTo.children('ul').append($nodeFrom);
          } else {
            $nodeTo.addClass('kv-parent');
            $(document.createElement('ul')).appendTo($nodeTo).append($nodeFrom);
          }

          showAlert(data.out, 'success');
          $tree.find('li.kv-collapsed').each(function() {
            if ($(this).has($nodeFrom).length > 0) {
              $(this).removeClass('kv-collapsed');
            }
          })
        }

        $tree.parent().removeClass('kv-loading-search');
      },
      error: function(jqXHR, textStatus, errorThrown) {
        showAlert(errorThrown, 'danger');
        $tree.parent().removeClass('kv-loading-search');
      },
    });
  }

  function showAlert(msg, type) {
    ('danger|warning|success'.indexOf(type) == -1) && (type = 'info')
    var $alert = $detail.find('.alert-' + type)

    $alert.append(msg).fadeIn('slow', function() {
      setTimeout(function() {
                $alert.fadeOut('slow')
      }, __tv.alertFadeDuration)
    })
  }
})(document.querySelector('[data-krajee-treeview]').id)

TreeController.php

<?php //controllers/TreeController.php
namespace app\controllers;

use Yii;

class TreeController extends \yii\web\Controller
{
    public function actionIndex() {
        return $this->render('index');
    }

    public function actionInput() {
        return $this->render('_index');
    }

    public function actionMove() {
        $dir = $idTo = $idFrom = $treeMoveHash = '';
        extract(Yii::$app->request->post());

        $nodeFrom = \app\ext\tree\Node::findOne($idFrom);
        $nodeTo = \app\ext\tree\Node::findOne($idTo);
        $nodeFrom->appendTo($nodeTo);

        \Yii::$app->response->format = 'json';
        return ['status' => 'success', 'out' => Yii::t('kvtree', 'The node was moved successfully.') ];
    }
}

TreeView.php

<?php //ext/tree/TreeView.php
namespace app\ext\tree;

use yii\helpers\Url;
use yii\helpers\Html;
use Yii;

class TreeView extends \kartik\tree\TreeView
{
    public function getActions() {
        return [
            'move' => Url::toRoute('tree/move'),
        ];
    }

    public function init() {
        parent::init();

        $this->view->registerAssetBundle(TreeViewAsset::className());
        $tvScrollTop = (int) Yii::$app->session['tvScrollTop'];

        $this->view->registerJs("
            jQuery('#{$this->id}-nodeform')
                .prepend('<input name=tvScrollTop value=$tvScrollTop type=hidden>')
            jQuery('#{$this->id}-tree').scrollTop($tvScrollTop)
            jQuery('#{$this->id}').data('moveAction', '{$this->actions['move']}')
        ");
    }

    public function renderTree() {
        $roots = Node::find()->roots()->all();

        return Html::tag('div',
                $this->renderRoot().
                $this->renderNodes($roots, ['class' => 'kv-tree']),
            $this->treeOptions);
    }

    public function renderNodes($nodes, $options = []) {
        $items = [];
        $structure = $this->_module->treeStructure + $this->_module->dataStructure;
        extract($structure);
        $nodeDepth = $currDepth = $counter = 0;

        foreach ($nodes as $node) {
            if (!$this->isAdmin && !$node->isVisible() || !$this->showInactive && !$node->isActive()) {
                continue;
            }

            /** @noinspection PhpUndefinedVariableInspection */
            $nodeDepth = $node->$depthAttribute;
            /** @noinspection PhpUndefinedVariableInspection */
            $nodeLeft = $node->$leftAttribute;
            /** @noinspection PhpUndefinedVariableInspection */
            $nodeRight = $node->$rightAttribute;
            /** @noinspection PhpUndefinedVariableInspection */
            $nodeKey = $node->$keyAttribute;
            /** @noinspection PhpUndefinedVariableInspection */
            $nodeName = $node->$nameAttribute;
            /** @noinspection PhpUndefinedVariableInspection */
            $nodeIcon = $node->$iconAttribute;
            /** @noinspection PhpUndefinedVariableInspection */
            $nodeIconType = $node->$iconTypeAttribute;

            $indicators = '';

            if (isset($this->nodeLabel)) {
                $label = $this->nodeLabel;
                $nodeName = is_callable($label) ? $label($node) :
                    (is_array($label) ? ArrayHelper::getValue($label, $nodeKey, $nodeName)
                                      : $nodeName);
            }

            $nodeName = $node->id . ') '.$nodeName;

            if (trim($indicators) == null) {
                $indicators = '&nbsp;';
            }
            $nodeOptions = [
                'data-key' => $nodeKey,
                'data-lft' => $nodeLeft,
                'data-rgt' => $nodeRight,
                'data-lvl' => $nodeDepth,
                'data-readonly' => static::parseBool($node->isReadonly()),
                'data-movable-u' => static::parseBool($node->isMovable('u')),
                'data-movable-d' => static::parseBool($node->isMovable('d')),
                'data-movable-l' => static::parseBool($node->isMovable('l')),
                'data-movable-r' => static::parseBool($node->isMovable('r')),
                'data-removable' => static::parseBool($node->isRemovable()),
                'data-removable-all' => static::parseBool($node->isRemovableAll()),
            ];

            $children = $node->children(1)->all();
            $css = [];

            if (!empty($children)) {
                $css[] = 'kv-parent';
            }
            if (!$node->isVisible() && $this->isAdmin) {
                $css[] = 'kv-invisible';
            }
            if ($this->showCheckbox && $node->isSelected()) {
                $css[] = 'kv-selected';
            }
            if ($node->isCollapsed()) {
                $css[] = 'kv-collapsed';
            }
            if ($node->isDisabled()) {
                $css[] = 'kv-disabled';
            }
            if (!$node->isActive()) {
                $css[] = 'kv-inactive';
            }
            $indicators .= $this->renderToggleIconContainer(false) . "\n";
            $indicators .= $this->showCheckbox ? $this->renderCheckboxIconContainer(false) . "\n" : '';

            if (!empty($css)) {
                Html::addCssClass($nodeOptions, $css);
            }

            $items[] = Html::tag('li',
                "<div tabindex='-1' class='kv-tree-list'>\n".
                "   <div class='kv-node-indicators'>\n{$indicators}\n</div>\n".
                "   <div tabindex=-1 class=kv-node-detail>\n".
                        $this->renderNodeIcon($nodeIcon, $nodeIconType, empty($children)) . "\n".
                "       <span class='kv-node-label'>". $nodeName ."</span>".
                "   </div>\n".
                "</div>\n".
                (!empty($children) ? $this->renderNodes($children) : ''),
            $nodeOptions);
        }

        return Html::tag('ul', implode('', $items), $options);
    }

    public function renderToolbar() {
        $_toolbar = $this->toolbar;
        $this->toolbar = array_slice($_toolbar, 0, 8, true);
        $this->toolbar += [
            'cut' => [
                'icon' => 'move',
                'options' => ['title' => Yii::t('app', 'Cut'), 'disabled' => true]
            ],
//            'paste' => [
//                'icon' => 'paste',
//                'options' => ['title' => Yii::t('app', 'Paste'), 'disabled' => true]
//            ]
        ];
        $this->toolbar += array_slice($_toolbar, -2, 3, true);

        return parent::renderToolbar();
    }
}

TreeViewAsset.php

<?php //ext/tree/TreeViewAsset.php
namespace app\ext\tree;

class TreeViewAsset extends \yii\web\AssetBundle
{
    public $sourcePath = __DIR__.'/assets';
    public $js = ['tree.js'];
    public $depends = ['kartik\tree\TreeViewAsset'];
    public $publishOptions = ['forceCopy' => true];
}