java swing动态添加组件

问题描述

我很喜欢Java Swing。我有一些怀疑在Swing中动态组件。

基本上我有一个主要 JPanel 由两个子 JPanel （leftpanel和rightpanel），它水平排列。在左边 JPanel 我有一些 JButtons ，当我点击 JButton 我确定显示一些 JLabel ， JTextArea 等在右边的 JPanel 。我尝试了一个代码，但它不工作。当我点击按钮，它进入事件侦听器功能，但 JLabel 我无法查看。

我在下面给我的代码看看这个并纠正我。感谢提前

 包我的; 
 
 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（系统管理员）; 
 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）; 
} 
}）; 
} 
} 
  

解决方案

你在添加（或删除）组件后需要调用 revalidate

  rightPanel 。新增（标签）; 
 rightPanel.revalidate（）; 
  

应该做的伎俩。

I am new to Java Swing. I have some doubt regarding adiing components dynamically in Swing.

Basically I hav one Main JPanel consisting of two sub JPanel (leftpanel and rightpanel ) which alligned horizontally.In left JPanel I hav some JButtons, when I will click on JButton I nedd to show some JLabel, JTextArea etc in right JPanel. I tried a code but its not working .When I click on the button its going inside the event listener function but JLabel I am not able to view.

I am giving my code below. Pls look at this and correct me. thanks in advance

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);
                }
            });
        }
    }

解决方案

You need to call revalidate after adding (or removing) components:

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

should do the trick.

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