import org.openide.explorer.view.NodeListModel; //导入依赖的package包/类
ToolBarView(final ExplorerManager manager, org.openide.nodes.Node root, javax.swing.Action helpAction) {
    super();
    this.manager=manager;
    this.helpAction=helpAction;
    // same as before...
    
    setLayout(new java.awt.GridBagLayout());
    ActionMap map = getActionMap();
    // ...and initialization of lookup variable
    lookup = ExplorerUtils.createLookup (manager, map);

    ChoiceView cView = new ChoiceView();
    ((NodeListModel)(cView.getModel())).setNode(root);
    setFloatable(false);
    ((NodeListModel)(cView.getModel())).setDepth(5);
    
    java.awt.GridBagConstraints gridBagConstraints = new java.awt.GridBagConstraints();
    gridBagConstraints.gridx = 0;
    gridBagConstraints.gridy = 0;
    gridBagConstraints.insets = new java.awt.Insets(0, 2, 4, 0);
    add(cView,gridBagConstraints);
    
    gridBagConstraints = new java.awt.GridBagConstraints();
    gridBagConstraints.gridx = 1;
    gridBagConstraints.gridy = 0;
    gridBagConstraints.weightx = 1.0;
    JPanel filler = new JPanel();
    add(filler,gridBagConstraints);
    
    javax.swing.JButton helpButton = new javax.swing.JButton(helpAction);
    helpButton.setText("");
    helpButton.setContentAreaFilled(false);
    helpButton.setFocusPainted(false);
    helpButton.setBorderPainted(false);
    gridBagConstraints = new java.awt.GridBagConstraints();
    gridBagConstraints.gridx = 2;
    gridBagConstraints.gridy = 0;
    //gridBagConstraints.weightx = 1.0;
    add(helpButton,gridBagConstraints);
}
 

import org.openide.explorer.view.NodeListModel; //导入依赖的package包/类
@Override
protected NodeListModel createModel() {
    return new CheckNodeListModel();
}