java swing动态添加组件

Question

我是Java Swing的新手.我对在Swing中动态添加组件有一些疑问.

基本上我甲肝一个主要JPanel由两个子JPanel(leftpanel和rightpanel)的神韵:horizo​​ntally.In离开JPanel我甲肝一些JButtons,我会点击JButton我NEDD表现出一定的JLabel,JTextArea等右JPanel.我尝试了一个代码,但它不起作用.当我点击按钮时,它进入事件监听器功能,但JLabel我无法查看.

我在下面给出我的代码.请看看这个并纠正我.提前致谢

package my;

    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import javax.swing.BoxLayout;
    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;
    import javax.swing.SwingUtilities;

    /**
     *
     * @author root
     */

    public class myAplliwithPanel extends JFrame{

        JPanel rightPanel;

        public myAplliwithPanel() {
             initGui();
        }        

        public void initGui()
        {
           JPanel mainPanel=new JPanel();
           mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.X_AXIS));

           JPanel leftPanel=new JPanel();
           leftPanel.setLayout(new BoxLayout(leftPanel, BoxLayout.Y_AXIS));

            rightPanel=new JPanel();
           rightPanel.setLayout(new BoxLayout(rightPanel, BoxLayout.Y_AXIS));

           JButton dbBut=new JButton("DB");
           JButton appliBut=new JButton("Appli");
           appliBut.addActionListener(new ActionListener() {

                public void actionPerformed(ActionEvent arg0) {
                    JLabel label=new JLabel("dsggs");
                   rightPanel.add(label);
                }
            });

           JButton backendBut=new JButton("Backend");

           leftPanel.add(dbBut);
           leftPanel.add(appliBut);
           leftPanel.add(backendBut);    

           mainPanel.add(leftPanel);
           mainPanel.add(rightPanel);

           add(mainPanel);

            setTitle("System Manger");
            setSize(400, 400);
            setLocationRelativeTo(null);
            setDefaultCloseOperation(EXIT_ON_CLOSE);


        }

    public static void main(String args[]) {
            SwingUtilities.invokeLater(new Runnable() {

                public void run() {
                    myAplliwithPanel myObj = new myAplliwithPanel();
                    myObj.setVisible(true);
                }
            });
        }
    }

Answer 1

您需要revalidate在添加(或删除)组件后调用:

rightPanel.add(label);
rightPanel.revalidate();

应该做的伎俩.

Answer 2

呼叫

rightPanel.revalidate();
rightPanel.repaint();

添加后