자바 - Swing 컨테이너 구조 (Glasspane, JMenuBar와 ContentPane, LayeredPane)

1) GlassPane

GlassPane은 다른 패널 위에 존재하면서 기본적으로 숨겨져 있는 투명한 판이다

 

예시 코드

import javax.swing.*;
import java.awt.*;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.MouseEvent;
import javax.swing.event.MouseInputAdapter;

/** An application that requires no other files. */
public class GlassPaneDemo {
    static private MyGlassPane myGlassPane;

    /**
     * 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("GlassPaneDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Start creating and adding components.
        JCheckBox changeButton =
                new JCheckBox("Glass pane \"visible\"");
        changeButton.setSelected(false);
        
        //Set up the content pane, where the "main GUI" lives.
        Container contentPane = frame.getContentPane();
        contentPane.setLayout(new FlowLayout());
        contentPane.add(changeButton);
        contentPane.add(new JButton("Button 1"));
        contentPane.add(new JButton("Button 2"));

        //Set up the menu bar, which appears above the content pane.
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("Menu");
        menu.add(new JMenuItem("Do nothing"));
        menuBar.add(menu);
        frame.setJMenuBar(menuBar);

        //Set up the glass pane, which appears over both menu bar
        //and content pane and is an item listener on the change
        //button.
        myGlassPane = new MyGlassPane(changeButton, menuBar,
                                      frame.getContentPane());
        changeButton.addItemListener(myGlassPane);
        frame.setGlassPane(myGlassPane);

        //Show the window.
        frame.pack();
        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();
	        }
	    });
	}
}
/**
 * We have to provide our own glass pane so that it can paint.
 */
class MyGlassPane extends JComponent
                  implements ItemListener {
    Point point;

    //React to change button clicks.
    public void itemStateChanged(ItemEvent e) {
        setVisible(e.getStateChange() == ItemEvent.SELECTED);
    }

    protected void paintComponent(Graphics g) {
        if (point != null) {
            g.setColor(Color.red);
            g.fillOval(point.x - 10, point.y - 10, 20, 20);
        }
    }

    public void setPoint(Point p) {
        point = p;
    }

    public MyGlassPane(AbstractButton aButton,
                       JMenuBar menuBar,
                       Container contentPane) {
        CBListener listener = new CBListener(aButton, menuBar,
                                             this, contentPane);
        addMouseListener(listener);
        addMouseMotionListener(listener);
    }
}

/**
 * Listen for all events that our check box is likely to be
 * interested in.  Redispatch them to the check box.
 */
class CBListener extends MouseInputAdapter {
    Toolkit toolkit;
    Component liveButton;
    JMenuBar menuBar;
    MyGlassPane glassPane;
    Container contentPane;

    public CBListener(Component liveButton, JMenuBar menuBar,
                      MyGlassPane glassPane, Container contentPane) {
        toolkit = Toolkit.getDefaultToolkit();
        this.liveButton = liveButton;
        this.menuBar = menuBar;
        this.glassPane = glassPane;
        this.contentPane = contentPane;
    }

    public void mouseMoved(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    public void mouseDragged(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    public void mouseClicked(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    public void mouseEntered(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    public void mouseExited(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    public void mousePressed(MouseEvent e) {
        redispatchMouseEvent(e, false);
    }

    public void mouseReleased(MouseEvent e) {
        redispatchMouseEvent(e, true);
    }

    //A basic implementation of redispatching events.
    private void redispatchMouseEvent(MouseEvent e,
                                      boolean repaint) {
        Point glassPanePoint = e.getPoint();
        Container container = contentPane;
        Point containerPoint = SwingUtilities.convertPoint(
                                        glassPane,
                                        glassPanePoint,
                                        contentPane);
        if (containerPoint.y < 0) { //we're not in the content pane
            if (containerPoint.y + menuBar.getHeight() >= 0) { 
                //The mouse event is over the menu bar.
                //Could handle specially.
            } else { 
                //The mouse event is over non-system window 
                //decorations, such as the ones provided by
                //the Java look and feel.
                //Could handle specially.
            }
        } else {
            //The mouse event is probably over the content pane.
            //Find out exactly which component it's over.  
            Component component = 
                SwingUtilities.getDeepestComponentAt(
                                        container,
                                        containerPoint.x,
                                        containerPoint.y);
                            
            if ((component != null) 
                && (component.equals(liveButton))) {
                //Forward events over the check box.
                Point componentPoint = SwingUtilities.convertPoint(
                                            glassPane,
                                            glassPanePoint,
                                            component);
                component.dispatchEvent(new MouseEvent(component,
                                                     e.getID(),
                                                     e.getWhen(),
                                                     e.getModifiers(),
                                                     componentPoint.x,
                                                     componentPoint.y,
                                                     e.getClickCount(),
                                                     e.isPopupTrigger()));
            }
        }
        
        //Update the glass pane if requested.
        if (repaint) {
            glassPane.setPoint(glassPanePoint);
            glassPane.repaint();
        }
    }
}

- 실행 결과 -

 

 

2) JMenuBar와 ContentPane

JMenuBar는 메뉴가 포함되는 판이고, 그 아래 쪽에 있는 ContentPane은 버튼과 같은 UI 컴포 넌트가 배치되는 판이다.

 

예시 코드

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenuBar;

/* TopLevelDemo.java requires no other files. */
public class ContentPaneDemo {
    /**
     * 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("ContentPaneDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create the menu bar.  Make it have a green background.
        JMenuBar greenMenuBar = new JMenuBar();
        greenMenuBar.setOpaque(true);
        greenMenuBar.setBackground(new Color(154, 165, 127));
        greenMenuBar.setPreferredSize(new Dimension(200, 20));

        //Create a yellow label to put in the content pane.
        JLabel yellowLabel = new JLabel();
        yellowLabel.setOpaque(true);
        yellowLabel.setBackground(new Color(248, 213, 131));
        yellowLabel.setPreferredSize(new Dimension(300, 180));

        //Set the menu bar and add the label to the content pane.
        frame.setJMenuBar(greenMenuBar);
        frame.getContentPane().add(yellowLabel, BorderLayout.CENTER);
        frame.getContentPane().add(new JButton("Ok"), BorderLayout.SOUTH);

        //Display the window.
        frame.pack();
        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();
            }
        });
    }
}

- 실행 결과 - 

 

3) LayeredPane

여러 컴포넌트들이 겹쳐질 때 각 컴포넌트의 상하 위치를 결 정한다

 

예시코드

import javax.swing.*;
import javax.swing.border.*;
import javax.accessibility.*;

import java.awt.*;
import java.awt.event.*;

/* 
 * LayeredPaneDemo.java requires
 * images/dukeWaveRed.gif. 
 */
public class LayeredPaneDemo extends JPanel
                             implements ActionListener,
                                        MouseMotionListener {
    private String[] layerStrings = { "Yellow (0)", "Magenta (1)",
                                      "Cyan (2)",   "Red (3)",
                                      "Green (4)" };
    private Color[] layerColors = { Color.yellow, Color.magenta,
                                    Color.cyan,   Color.red,
                                    Color.green };

    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;

    public LayeredPaneDemo()    {
        setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));

        //Create and load the duke icon.
        final ImageIcon icon = createImageIcon("images/dukeWaveRed.gif");

        //Create and set up the layered pane.
        layeredPane = new JLayeredPane();
        layeredPane.setPreferredSize(new Dimension(300, 310));
        layeredPane.setBorder(BorderFactory.createTitledBorder(
                                    "Move the Mouse to Move Duke"));
        layeredPane.addMouseMotionListener(this);

        //This is the origin of the first label added.
        Point origin = new Point(10, 20);

        //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(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(2), 0);

        //Add control pane and layered pane to this JPanel.
        add(Box.createRigidArea(new Dimension(0, 10)));
        add(createControlPanel());
        add(Box.createRigidArea(new Dimension(0, 10)));
        add(layeredPane);
    }

    /** Returns an ImageIcon, or null if the path was invalid. */
    protected static ImageIcon createImageIcon(String path) {
        java.net.URL imgURL = LayeredPaneDemo.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(2);    //cyan layer
        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,
                                 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("LayeredPaneDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        //Create and set up the content pane.
        JComponent newContentPane = new LayeredPaneDemo();
        newContentPane.setOpaque(true); //content panes must be opaque
        frame.setContentPane(newContentPane);

        //Display the window.
        frame.pack();
        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();
            }
        });
    }
}

- 실행 결과 -