RootLayeredPaneDemo.java

/*
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 * modification, are permitted provided that the following conditions
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 *     notice, this list of conditions and the following disclaimer.
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 *   - Redistributions in binary form must reproduce the above copyright
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 *     documentation and/or other materials provided with the distribution.
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 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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package javademo.swing.pane;

import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Point;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;

import javax.swing.BorderFactory;
import javax.swing.ImageIcon;
import javax.swing.JCheckBox;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JLayeredPane;
import javax.swing.JPanel;

/*
 * RootLayeredPaneDemo.java requires images/dukeWaveRed.gif.
 */
public class RootLayeredPaneDemo extends JPanel implements ActionListener, MouseMotionListener
{
    private static final long serialVersionUID = 1L;
    
    private int[] layers = { -30000, 0, 301 };
    
    private String[] layerStrings = { "Yellow (-30000)", "Magenta (0)", "Cyan (301)" };
    
    private Color[] layerColors = { Color.yellow, Color.magenta, Color.cyan };
    
    private JLayeredPane layeredPane;
    
    private JLabel dukeLabel;
    
    private JCheckBox onTop;
    
    private JComboBox layerList;
    
    // Action commands
    private static String ON_TOP_COMMAND = "ontop";
    
    private static String LAYER_COMMAND = "layer";
    
    // Adjustments to put Duke's toe at the cursor's tip.
    private static final int XFUDGE = 40;
    
    private static final int YFUDGE = 57;
    
    // Initial layer of dukeLabel.
    private static final int INITIAL_DUKE_LAYER_INDEX = 1;
    
    public RootLayeredPaneDemo(JLayeredPane layeredPane)
    {
        super(new GridLayout(1, 1));
        
        // Create and load the duke icon.
        final ImageIcon icon = createImageIcon("images/dukeWaveRed.gif");
        
        // Create and set up the layered pane.
        this.layeredPane = layeredPane;
        layeredPane.addMouseMotionListener(this);
        
        // This is the origin of the first label added.
        Point origin = new Point(10, 100);
        
        // This is the offset for computing the origin for the next label.
        int offset = 35;
        
        // Add several overlapping, colored labels to the layered pane
        // using absolute positioning/sizing.
        for (int i = 0; i < layerStrings.length; i++)
        {
            JLabel label = createColoredLabel(layerStrings[i], layerColors[i], origin);
            layeredPane.add(label, new Integer(layers[i]));
            origin.x += offset;
            origin.y += offset;
        }
        
        // Create and add the Duke label to the layered pane.
        dukeLabel = new JLabel(icon);
        if (icon != null)
        {
            dukeLabel.setBounds(15, 225, icon.getIconWidth(), icon.getIconHeight());
        }
        else
        {
            System.err.println("Duke icon not found; using black square instead.");
            dukeLabel.setBounds(15, 225, 30, 30);
            dukeLabel.setOpaque(true);
            dukeLabel.setBackground(Color.BLACK);
        }
        layeredPane.add(dukeLabel, new Integer(layers[INITIAL_DUKE_LAYER_INDEX]), 0);
        
        // Add control pane to this JPanel.
        add(createControlPanel());
    }
    
    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path)
    {
        java.net.URL imgURL = RootLayeredPaneDemo.class.getResource(path);
        if (imgURL != null)
        {
            return new ImageIcon(imgURL);
        }
        else
        {
            System.err.println("Couldn't find file: " + path);
            return null;
        }
    }
    
    // Create and set up a colored label.
    private JLabel createColoredLabel(String text, Color color, Point origin)
    {
        JLabel label = new JLabel(text);
        label.setVerticalAlignment(JLabel.TOP);
        label.setHorizontalAlignment(JLabel.CENTER);
        label.setOpaque(true);
        label.setBackground(color);
        label.setForeground(Color.black);
        label.setBorder(BorderFactory.createLineBorder(Color.black));
        label.setBounds(origin.x, origin.y, 140, 140);
        return label;
    }
    
    // Create the control pane for the top of the frame.
    private JPanel createControlPanel()
    {
        onTop = new JCheckBox("Top Position in Layer");
        onTop.setSelected(true);
        onTop.setActionCommand(ON_TOP_COMMAND);
        onTop.addActionListener(this);
        
        layerList = new JComboBox(layerStrings);
        layerList.setSelectedIndex(INITIAL_DUKE_LAYER_INDEX);
        layerList.setActionCommand(LAYER_COMMAND);
        layerList.addActionListener(this);
        
        JPanel controls = new JPanel();
        controls.add(layerList);
        controls.add(onTop);
        controls.setBorder(BorderFactory.createTitledBorder("Choose Duke's Layer and Position"));
        return controls;
    }
    
    // Make Duke follow the cursor.
    public void mouseMoved(MouseEvent e)
    {
        dukeLabel.setLocation(e.getX() - XFUDGE, e.getY() - YFUDGE);
    }
    
    public void mouseDragged(MouseEvent e)
    {
    } // do nothing
    
    // Handle user interaction with the check box and combo box.
    public void actionPerformed(ActionEvent e)
    {
        String cmd = e.getActionCommand();
        
        if (ON_TOP_COMMAND.equals(cmd))
        {
            if (onTop.isSelected())
                layeredPane.moveToFront(dukeLabel);
            else
                layeredPane.moveToBack(dukeLabel);
            
        }
        else if (LAYER_COMMAND.equals(cmd))
        {
            int position = onTop.isSelected() ? 0 : -1;
            layeredPane.setLayer(dukeLabel, layers[layerList.getSelectedIndex()], position);
        }
    }
    
    /**
     * Create the GUI and show it.  For thread safety,
     * this method should be invoked from the
     * event-dispatching thread.
     */
    private static void createAndShowGUI()
    {
        // Create and set up the window.
        JFrame frame = new JFrame("RootLayeredPaneDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        
        // Create and set up the content pane.
        RootLayeredPaneDemo newContentPane = new RootLayeredPaneDemo(frame.getLayeredPane());
        newContentPane.setOpaque(true); // content panes must be opaque
        frame.setContentPane(newContentPane);
        
        // Display the window.
        frame.setSize(new Dimension(300, 350));
        frame.setVisible(true);
    }
    
    public static void main(String[] args)
    {
        // Schedule a job for the event-dispatching thread:
        // creating and showing this application's GUI.
        javax.swing.SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {
                createAndShowGUI();
            }
        });
    }
}