Context Menu

The context menu is not a control itself - it is part of existing controls. Context menus are supported by the following controls:

  • TEXTGRID2

  • TEXTGRIDSSS2

  • TREENODE2

  • CLIENTTREE

  • FIELD

All these controls have items that are represented by corresponding objects on the server side:

  • For the text grid controls, each row of the grid is represented by a certain object on the server side that is managed inside a TEXTGRIDCollection.

  • For the tree controls, each node of the tree is represented by a certain object (derived from NODEInfo) that is managed inside a TREECollection.

When the user right-clicks on an item, the method reactOnContextMenuRequest() is called inside the item's server-side object. When the user right-clicks in a FIELD control for which "myfield" has been defined with the valueprop property, the default name of the called method is reactOnContextMenuMyfield. In principle, your server-side implementation could do anything as reaction inside the implementation of the method - i.e. you do not have to open a context menu, but you can also do every other thing that you are able to do inside an adapter implementation.

To open a context menu, you proceed as follows:

  • You define a tree collection.

  • You add menu nodes to the tree collection - exactly in the same way as you do it with a normal MENU control.

  • You pass the tree collection to the adapter via its method showPopupMenu().

This document covers the following topics:

Example: Context Menu with a Text Grid

graphics/image154.png

There is no special specification necessary inside the layout definition of the corresponding TEXTGRID2/ TEXTGRIDSSS2 control. All you have to do is to implement the reactOnContextMenuRequest() method inside the class representing the items of the grid: 

public class MenuAdapter
    extends Model
{
    // ------------------------------------------------------------------------
    // inner classes
    // ------------------------------------------------------------------------

    /** class used for pop-up menu. */
    public class MyMenuNodeInfo
        extends MENUNODEInfo
    {
        public MyMenuNodeInfo(String text) { super(text); }
        public MyMenuNodeInfo(String text, String image) { super(text, image); }
        public void reactOnSelect()
        {
           outputMessage("S", "Menu Item \"" + getText() + "\" selected!");
        }
    }

    /** class represents one row within the text grid. */
    public class Line
    {
        String m_name;
        CTimeStamp m_htmlChange;
        CTimeStamp m_xmlChange;
        public Line(String name, CTimeStamp xmlChange, CTimeStamp htmlChange)
        {
            m_name = name;
            m_xmlChange = xmlChange;
            m_htmlChange = htmlChange;
        }
        public String getName() { return m_name; }
        public CTimeStamp getHtmlChange() { return m_htmlChange; }
        public CTimeStamp getXmlChange() { return m_xmlChange; }

        /** This method will be called if the line will be clicked with
         * the right mouse button.*/
        public void reactOnContextMenuRequest()
        {
            // prepare the appropriate popu menu content
            TREECollection menu = new TREECollection();
            menu.addTopNode(new MyMenuNodeInfo(
                        "Open in Layout Painter",
                        "../HTMLBasedGUI/images/open.gif"),true);
            menu.addTopNode(new MyMenuNodeInfo(
                        "Generate Adapter Code",
                        "../HTMLBasedGUI/images/java.gif"),true);
            menu.addTopNode(new MyMenuNodeInfo(
                        "Maintain Literals",
                        "../HTMLBasedGUI/images/literals.gif"),true);
            menu.addTopNode(new MyMenuNodeInfo(
                        "&SEPARATOR"),true);
            menu.addTopNode(new MyMenuNodeInfo(
                        "Remove (XML & HTML)",
                        "../HTMLBasedGUI/images/remove.gif"),true);

            // open the poup menu
            showPopupMenu(menu);
        }
    }

    ...
    ...
    ...
    ...
    ...

}

Pay attention: the showPopupMenu() method is provided by the class Adapter - in the implementation example, it is directly accessed from the class Line. The class Line is an inner class and consequently has full access to all the methods of its surrounding class.

Context Menu with a Tree

The implementation of a context menu in the tree is absolutely the same as with a text grid - this time you have to implement the reactOnContextMenuRequest() method inside the class representing one tree node.

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