import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class FatherFrame extends JFrame implements ActionListener {
    private JButton btn=new JButton("click");

    public JTextField getJtx() {
        return jtx;
    }

    private JTextField jtx=new JTextField(15);
    private JDialog   dialog=null;

    public FatherFrame(String title){
        super(title);
        Container c=this.getContentPane();
        c.setLayout(new FlowLayout());
        c.add(jtx);
        c.add(btn);
        btn.addActionListener(this);
        this.pack();
        this.setVisible(true);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLocationRelativeTo(null);
    }

    @Override
    public void actionPerformed(ActionEvent e) {
        dialog=new ChildDialog(this);

//        dialog.getParent();
    }

    public static void main(String[] args) {
        new FatherFrame("demo");
    }
}
class ChildDialog extends JDialog{
    private FatherFrame father=null;
    private JLabel label=null;
    private JTextArea jta=new JTextArea();

    public ChildDialog(FatherFrame fatherFrame){
        this.father=fatherFrame;
        jta.setText(father.getJtx().getText());
        label=new JLabel("以下是从父窗口获得的信息：");
        this.getContentPane().setLayout(new FlowLayout());
        this.getContentPane().add(label);
        this.getContentPane().add(jta);
        this.pack();
//        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
        this.setLocationRelativeTo(null);
    }
}