如何在运行时移动jpanel

Question

I am working on an application and I want the jpanel to move around inside jframe at run time. here is the code I used

package testing;

import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;


public class ChangePanel extends javax.swing.JFrame {


public ChangePanel() {
    initComponents();
}

@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jLabel1 = new javax.swing.JLabel();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
    getContentPane().setLayout(null);

    jPanel1.setBorder(javax.swing.BorderFactory.createEtchedBorder());
    jPanel1.addMouseListener(new java.awt.event.MouseAdapter() {
        public void mousePressed(java.awt.event.MouseEvent evt) {
            jPanel1MousePressed(evt);
        }
    });
    jPanel1.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
        public void mouseDragged(java.awt.event.MouseEvent evt) {
            jPanel1MouseDragged(evt);
        }
    });

    jLabel1.setText("panel to move");

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addGap(56, 56, 56)
            .addComponent(jLabel1)
            .addContainerGap(119, Short.MAX_VALUE))
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(jPanel1Layout.createSequentialGroup()
            .addGap(62, 62, 62)
            .addComponent(jLabel1)
            .addContainerGap(81, Short.MAX_VALUE))
    );

    getContentPane().add(jPanel1);
    jPanel1.setBounds(160, 60, 247, 161);

    pack();
}// </editor-fold>                        

private void jPanel1MouseDragged(java.awt.event.MouseEvent evt) {                                     

 MouseAdapter ma = new MouseAdapter() {

     int lastX =0, lastY =0;
 @Override
    public void mouseDragged(MouseEvent e) {


        int x = e.getXOnScreen();
        int y = e.getYOnScreen();
        // Move frame by the mouse delta
        setLocation(getLocationOnScreen().x + x - lastX,
                getLocationOnScreen().y + y - lastY);
        lastX = x;
        lastY = y;
    }
 };

}                                    

private void jPanel1MousePressed(java.awt.event.MouseEvent evt) {                                     

    MouseAdapter ma = new MouseAdapter() {
    int lastX, lastY;
    @Override
    public void mousePressed(MouseEvent e) {
        lastX = e.getXOnScreen();
        lastY = e.getYOnScreen();
    }};
}                                    

/**
 * @param args the command line arguments
 */
public static void main(String args[]) {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(ChangePanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(ChangePanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(ChangePanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(ChangePanel.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new ChangePanel().setVisible(true);
        }
    });
}

// Variables declaration - do not modify                     
private javax.swing.JLabel jLabel1;
private javax.swing.JPanel jPanel1;
// End of variables declaration                   
}

but is not working

Answer 1

Some time ago, I've written a framework for such tasks. Maybe you find it useful (the library is Open Source):

Tutorial:

http://softsmithy.sourceforge.net/lib/current/docs/tutorial/swing/customizer/index.html

Javadoc:

http://softsmithy.sourceforge.net/lib/current/docs/api/softsmithy-lib-swing-customizer/index.html

Info about the latest release:

http://puces-blog.blogspot.ch/2013/11/news-from-software-smithy-version-04.html

Answer 2

There's no need to put a MouseAdapter within an already defined Listener. In fact, you're simply declaring one and not using it in any way. Simply keep it inside the dragged event.

Like this. You can adapt it to the calculations you need to do.

    private void jPanel1MouseDragged(java.awt.event.MouseEvent evt) {                                     
        jPanel1.setLocation(evt.getXOnScreen(), evt.getYOnScreen());
    }