调整java swing应用程序中没有Jframe的jpanel的大小

Question

作为学习的一部分，我在一个简单的swing应用程序中制作了一个JPanel。我把它弄得没装饰。现在只显示了一个JPanel。我应用了组件移动和添加关闭按钮到这个面板，但面板的大小是固定的。

如何使JPanel可调整大小？

包X；公共类TestRun扩展javax.swing.jframe{

/**
 * Creates new form TestRun
 */
public TestRun() {
    setUndecorated(true);
    initComponents();
    setMouseListener();
}
private void setMouseListener() {
    MoveMouseListener mlistener = new MoveMouseListener(jMenuBar1);
    jMenuBar1.addMouseListener(mlistener);
    jMenuBar1.addMouseMotionListener(mlistener);
}
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">                          
private void initComponents() {

    jPanel1 = new javax.swing.JPanel();
    jMenuBar1 = new javax.swing.JMenuBar();
    jMenu1 = new javax.swing.JMenu();
    jMenu2 = new javax.swing.JMenu();
    jMenuItem1 = new javax.swing.JMenuItem();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 1090, Short.MAX_VALUE)
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGap(0, 689, Short.MAX_VALUE)
    );

    jMenu1.setText("File");
    jMenuBar1.add(jMenu1);

    jMenu2.setText("Exit");

    jMenuItem1.setText("Exit");
    jMenuItem1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jMenuItem1ActionPerformed(evt);
        }
    });
    jMenu2.add(jMenuItem1);

    jMenuBar1.add(jMenu2);

    setJMenuBar(jMenuBar1);

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addComponent(jPanel1, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );

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

private void jMenuItem1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
    // TODO add your handling code here:
    System.exit(EXIT_ON_CLOSE);
}                                          

/**
 * @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(TestRun.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(TestRun.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(TestRun.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(TestRun.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 TestRun().setVisible(true);
        }
    });
}

// Variables declaration - do not modify                     
private javax.swing.JMenu jMenu1;
private javax.swing.JMenu jMenu2;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem jMenuItem1;
private javax.swing.JPanel jPanel1;
// End of variables declaration                   

}

Answer 1

您应该能够在JPanel上使用setPreferredSize（维度大小）；并在JFrame上调用pack()；