没有将表添加到操作面板中

Question

package gestiune;
import java.awt.event.ActionEvent;
import javax.swing.*;
import java.awt.*;

public class Gestiune {
    static Gest gest;
    static Action actListaAng;    
    static JPanel panouPrinc;
    static ListaAngajati lang;
    static JMenuItem listaAng;
    static class Gest extends JFrame{
     public Gest(){                
            actListaAng = new ActListaAng("List");
            listaAng=new JMenuItem(actListaAng);
            panouPrinc = new JPanel();
            panouPrinc.setBackground(Color.white);
            Container cp = getContentPane();            
            cp.add(panouPrinc);
            pack();
            setTitle("Some title");
            setSize(1000,700);
            setLocation(0,0);
            setVisible(true);            
            setDefaultCloseOperation(DISPOSE_ON_CLOSE);
        }
    }        

    public static void main(String[] args) {
        gest = new Gest();
    }

    //class for listing action
    static class ActListaAng extends AbstractAction {

        public ActListaAng(String text){
            super(text);
        }

        @Override
        public void actionPerformed(ActionEvent e) {
            lang = new ListaAngajati();
            panouPrinc.add(lang);
        }
    }
}

下面是表类：

package gestiune;
import javax.swing.*;
import java.awt.*;

public class ListaAngajati extends JPanel {
    JTable tabel;
    JScrollPane panouScroll;
    public ListaAngajati() {
        panouScroll = new JScrollPane(tabel);
        String[] numeCol = {
        "Nume",
        "Prenume",
        "Categorie",
        "Data Adaugare",
        "Ultima Modificare"
    };

    Object[][] linii = {
        {"verban","adrian","sds","16-03-1989","acum"}
    };    
    tabel = new JTable(linii,numeCol);
    setLayout(new BorderLayout());
    add(tabel.getTableHeader(), BorderLayout.PAGE_START);
    add(panouScroll);
    add(tabel);

    }    

}

我尝试了几种方法，比如在ActionEvent上使用repaint，或者直接在table类中使用repaint.......如果我添加lang=new ListaAngajati（）；panouprinc.add（lang）；直接进入主jframe构造函数工作，但从操作上它就不工作了，所以我有点没有选择了，所以有人能帮我一把吗？

Answer 1

如果您revalidate()和repaint()，它可以工作。在运行时添加组件后，您应该始终revalidate()和repaint()。

@Override
public void actionPerformed(ActionEvent e){
    lang=new ListaAngajati();
    panouPrinc.add(lang);
    panouPrinc.revalidate();
    panouPrinc.repaint();
}

也没有按钮可以点击，所以我在这里添加了一个按钮，并添加了操作

Container cp=getContentPane(); 
JButton button = new JButton(new ActListaAng("Action"));
button.setText("Open");
cp.add(button, BorderLayout.PAGE_START);
cp.add(panouPrinc);
pack();

很好用。