帮我看看问题在哪儿

[Smopuim]

public class E4 extends JFrame{
private JDialog jd;
private JButton jb;
private JLabel jl;
public E4(){
JFrame jf=new JFrame("事件");
jb=new JButton("开始");
jl=new JLabel("结果");
jd=new JDialog(this,"对话框",true);
jd.setBounds(200,200,200,200);
JTextField jta=new JTextField("");
String s=jta.getText();
jl.setText(s);
jb.addActionListener(new MyListener());
jf.setLayout(new FlowLayout());
jf.add(jb);
jd.add(jl);
jf.add(jta);
setBounds(400,400,400,400);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setSize(400,400);
jf.setVisible(true);
}
class MyListener implements ActionListener{
public void actionPerformed(ActionEvent e){
jd.setVisible(true);
}}
public static void main(String[] args) {
// TODO Auto-generated method stub
new E4();
}

一个小练习，在文本域输入字符，然后在JDialog显示刚才输入的字符，可是这个程序的结果是JDialog没显示刚才输入的结果，求大神指点

[小小X]

public class E4 extends JFrame {
private JDialog jd;
private JButton jb;
private JLabel jl;
private JTextField jta;
public E4() {
JFrame jf = new JFrame("事件");
jb = new JButton("开始");
jl = new JLabel("结果");
jd = new JDialog(this, "对话框", true);
jd.setBounds(200, 200, 200, 200);
jta = new JTextField(10);
jb.addActionListener(new MyListener());
jf.setLayout(new FlowLayout());
jf.add(jb);
jf.add(jta);
setBounds(400, 400, 400, 400);
jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
jf.setSize(400, 400);
jf.setVisible(true);
}

class MyListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
jl = new JLabel("结果");
jl.setText(jta.getText());
jd.add(jl);
jd.setVisible(true);
}
}

public static void main(String[] args) {
// TODO Auto-generated method stub
new E4();
}
}

[五哥]

楼上正解，你的

import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class E4 extends JFrame {
	private JDialog jd;
	private JButton jb;
	private JLabel jl;
	private JTextField jta ; //把这个放出来 ，因为你的点击事件重要取出来

	public E4() {
		JFrame jf = new JFrame("事件");
		jb = new JButton("开始");
		jl = new JLabel("结果");
		jd = new JDialog(this, "对话框", true);
		jd.setBounds(100, 100, 200, 200);
		jta = new JTextField(15);
		String s = jta.getText();
		jl.setText(s);
		jb.addActionListener(new MyListener());
		jf.setLayout(new FlowLayout());
		jf.add(jb);
//		jd.add(jl); //这时候还没有数据 ，可以不要放上去
		jf.add(jta);
		setBounds(400, 400, 400, 400);
		jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		jf.setSize(400, 400);
		jf.setVisible(true);
	}

	class MyListener implements ActionListener {
		public void actionPerformed(ActionEvent e) {
			jl.setText(jta.getText());//设置完数据
			jd.add(jl); //加到对话框上
			jd.setVisible(true);

		}
	}

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		new E4();
	}
}