JToggleButtonMenuItem.java Source code

Introduction

Here is the source code for JToggleButtonMenuItem.java

Source

import java.awt.Color;
import java.awt.Component;
import java.awt.Point;
import java.awt.event.KeyEvent;
import java.awt.event.MouseEvent;

import javax.swing.ButtonModel;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JToggleButton;
import javax.swing.MenuElement;
import javax.swing.MenuSelectionManager;
import javax.swing.event.MouseInputListener;

class JToggleButtonMenuItem extends JToggleButton implements MenuElement {
    Color savedForeground = null;

    private static MenuElement NO_SUB_ELEMENTS[] = new MenuElement[0];

    public JToggleButtonMenuItem(String label) {
        super(label);
        init();
    }

    private void init() {
        updateUI();
        setRequestFocusEnabled(false);
        // Borrows heavily from BasicMenuUI
        MouseInputListener mouseInputListener = new MouseInputListener() {
            // If mouse released over this menu item, activate it
            public void mouseReleased(MouseEvent mouseEvent) {
                MenuSelectionManager menuSelectionManager = MenuSelectionManager.defaultManager();
                Point point = mouseEvent.getPoint();
                if ((point.x >= 0) && (point.x < getWidth()) && (point.y >= 0) && (point.y < getHeight())) {
                    menuSelectionManager.clearSelectedPath();
                    // Component automatically handles "selection" at this point
                    // doClick(0); // not necessary
                } else {
                    menuSelectionManager.processMouseEvent(mouseEvent);
                }
            }

            // If mouse moves over menu item, add to selection path, so it becomes
            // armed
            public void mouseEntered(MouseEvent mouseEvent) {
                MenuSelectionManager menuSelectionManager = MenuSelectionManager.defaultManager();
                menuSelectionManager.setSelectedPath(getPath());
            }

            // When mouse moves away from menu item, disarm it and select something
            // else
            public void mouseExited(MouseEvent mouseEvent) {
                MenuSelectionManager menuSelectionManager = MenuSelectionManager.defaultManager();
                MenuElement path[] = menuSelectionManager.getSelectedPath();
                if (path.length > 1) {
                    MenuElement newPath[] = new MenuElement[path.length - 1];
                    for (int i = 0, c = path.length - 1; i < c; i++) {
                        newPath[i] = path[i];
                    }
                    menuSelectionManager.setSelectedPath(newPath);
                }
            }

            // Pass along drag events
            public void mouseDragged(MouseEvent mouseEvent) {
                MenuSelectionManager.defaultManager().processMouseEvent(mouseEvent);
            }

            public void mouseClicked(MouseEvent mouseEvent) {
            }

            public void mousePressed(MouseEvent mouseEvent) {
            }

            public void mouseMoved(MouseEvent mouseEvent) {
            }
        };
        addMouseListener(mouseInputListener);
        addMouseMotionListener(mouseInputListener);
    }

    // MenuElement methods
    public Component getComponent() {
        return this;
    }

    public MenuElement[] getSubElements() {
        // No subelements
        return NO_SUB_ELEMENTS;
    }

    public void menuSelectionChanged(boolean isIncluded) {
        ButtonModel model = getModel();
        // Only change armed state if different
        if (model.isArmed() != isIncluded) {
            model.setArmed(isIncluded);
        }

        if (isIncluded) {
            savedForeground = getForeground();
            if (!savedForeground.equals(Color.BLUE)) {
                setForeground(Color.BLUE);
            } else {
                // In case foreground blue, use something different
                setForeground(Color.RED);
            }
        } else {
            setForeground(savedForeground);
            // If null, get foreground from installed look and feel
            if (savedForeground == null) {
                updateUI();
            }
        }
    }

    public void processKeyEvent(KeyEvent keyEvent, MenuElement path[], MenuSelectionManager manager) {
        // If user presses space while menu item armed, select it
        if (getModel().isArmed()) {
            int keyChar = keyEvent.getKeyChar();
            if (keyChar == KeyEvent.VK_SPACE) {
                manager.clearSelectedPath();
                System.out.println("Selected: JToggleButtonMenuItem, by KeyEvent");
                doClick(0); // inherited from AbstractButton
            }
        }
    }

    public void processMouseEvent(MouseEvent mouseEvent, MenuElement path[], MenuSelectionManager manager) {
        // For when mouse dragged over menu and button released
        if (mouseEvent.getID() == MouseEvent.MOUSE_RELEASED) {
            manager.clearSelectedPath();
            System.out.println("Selected: JToggleButtonMenuItem, by MouseEvent");
            doClick(0); // inherited from AbstractButton
        }
    }

    // Borrows heavily from BasicMenuItemUI.getPath()
    private MenuElement[] getPath() {
        MenuSelectionManager menuSelectionManager = MenuSelectionManager.defaultManager();
        MenuElement oldPath[] = menuSelectionManager.getSelectedPath();
        MenuElement newPath[];
        int oldPathLength = oldPath.length;
        if (oldPathLength == 0)
            return new MenuElement[0];
        Component parent = getParent();
        if (oldPath[oldPathLength - 1].getComponent() == parent) {
            // Going deeper under the parent menu
            newPath = new MenuElement[oldPathLength + 1];
            System.arraycopy(oldPath, 0, newPath, 0, oldPathLength);
            newPath[oldPathLength] = this;
        } else {
            // Sibling/child menu item currently selected
            int newPathPosition;
            for (newPathPosition = oldPath.length - 1; newPathPosition >= 0; newPathPosition--) {
                if (oldPath[newPathPosition].getComponent() == parent) {
                    break;
                }
            }
            newPath = new MenuElement[newPathPosition + 2];
            System.arraycopy(oldPath, 0, newPath, 0, newPathPosition + 1);
            newPath[newPathPosition + 1] = this;
        }
        return newPath;
    }
}

public class JToggleButtonMenuItemDemo {
    public static void main(final String args[]) {
        JFrame frame = new JFrame("MenuSample Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JMenuBar menuBar = new JMenuBar();

        // File Menu, F - Mnemonic
        JMenu fileMenu = new JMenu("File");
        fileMenu.setMnemonic(KeyEvent.VK_F);
        menuBar.add(fileMenu);

        // File->New, N - Mnemonic
        JToggleButtonMenuItem newMenuItem = new JToggleButtonMenuItem("New");
        fileMenu.add(newMenuItem);

        frame.setJMenuBar(menuBar);
        frame.setSize(350, 250);
        frame.setVisible(true);
    }
}