如何将一个控件置于最上层（在线等待）

import javax.swing.*;
import javax.swing.border.*;
import javax.accessibility.*;import java.awt.*;
import java.awt.event.*;/*
* LayeredPaneDemo2.java is a 1.4 application that 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)",  "Blue (5)" };
    private Color[] layerColors = { Color.yellow, Color.magenta,
                                    Color.cyan,   Color.red,
                                    Color.green,  Color.blue };    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";    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);        //Add several labels to the layered pane.
        layeredPane.setLayout(new GridLayout(2,3));
        for (int i = 0; i < layerStrings.length; i++) {
            JLabel label = createColoredLabel(layerStrings[i],
                                              layerColors[i]);
            layeredPane.add(label, new Integer(i));
        }        //Create and add the Duke label to the layered pane.
        dukeLabel = new JLabel(icon);
        if (icon == null) {
            System.err.println("Duke icon not found; using black rectangle instead.");
            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) {
        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.setPreferredSize(new Dimension(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()-dukeLabel.getWidth()/2,
                              e.getY()-dukeLabel.getHeight()/2);
    }
    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() {
        //Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);        //Create and set up the window.
        JFrame frame = new JFrame("LayeredPaneDemo2");
        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();
            }
        });
    }
}
对于上面置影片播放的JPanel就失效了，是不是因为加载速度慢了点（它出现的速度就比其它慢一拍），这个JPanel就移不到下面去，其它的JPanel一个置图片，一个置文本，不知道怎么做？
下面这个也许更简单明了，你试着改改JLabel为其他Component就行（我下线了）：import javax.swing.*;
import java.awt.*;public class JLayeredPaneTest extends JPanel
{
public JLayeredPaneTest() {
setLayout( new BorderLayout() ); JLayeredPane layeredPane = new JLayeredPane();
layeredPane.setPreferredSize(new Dimension(300, 310));
layeredPane.setBorder(BorderFactory.createTitledBorder( "测试"));
JLabel blueLabel = new JLabel();
blueLabel.setVerticalAlignment(JLabel.TOP);
        blueLabel.setHorizontalAlignment(JLabel.CENTER);
blueLabel.setOpaque(true);
blueLabel.setBounds( 20,20,100,100 );
blueLabel.setBackground( Color.blue ); JLabel redLabel = new JLabel();
redLabel.setVerticalAlignment(JLabel.TOP);
        redLabel.setHorizontalAlignment(JLabel.CENTER);
redLabel.setOpaque(true);
redLabel.setBounds( 80,80,100,100 );
redLabel.setBackground( Color.red ); layeredPane.add( blueLabel,new Integer(1) );
layeredPane.add( redLabel,new Integer(5) ); add( layeredPane,BorderLayout.CENTER );
setOpaque( true );
} private static void createAndShowUI() {
//Make sure we have nice window decorations.
        JFrame.setDefaultLookAndFeelDecorated(true);        //Create and set up the window.
        JFrame frame = new JFrame("LayeredPaneDemo");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setContentPane( new JLayeredPaneTest() );        //Display the window.
        frame.pack();
        frame.setVisible(true);
} public static void main(String[] args)
{
javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowUI();
            }
        });
}
}

调试易

如何将一个控件置于最上层（在线等待）

解决方案 »