[java]ActionEvent事件：获取输入字符串的长度

Example9_7.java
public class Example9_7
{
public static void main(String args[]){
WindowActionEvent win= new WindowActionEvent();
PoliceListen police = new PoliceListen();//创建监视器
win.setMyCommandListener(police);
win.setBounds(100,100,460,360);
win.setTitle("处理ActionEvent事件");
}
}

WindowActionEvent.java
import java.awt.*;
import javax.swing.*;
public class WindowActionEvent extends JFrame
{
JTextField inputText;
JTextArea textShow;
JButton button;
MyCommandListener listener;
public WindowActionEvent(){
init();
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
void init(){
setLayout(new FlowLayout());
inputText = new JTextField(10);
button = new JButton("确定");
textShow=new JTextArea(9,30);
add(inputText);
add(button);
add(new JScrollPane(textShow));
}
void setMyCommandListener(MyCommandListener listener){
this.listener=listener;
listener.setJTextField(inputText);
listener.setJTextArea(textShow);
inputText.addActionListener(listener);
button.addActionListener(listener);
}
}

MyCommandListener.java
import javax.swing.*;
import java.awt.event.*;
interface MyCommandListener extends ActionListener
{
public void setJTextField(JTextField text);
public void setJTextArea(JTextArea area);
}

PoliceListen.java
import java.awt.event.*;
import javax.swing.*;
public class PoliceListen implements MyCommandListener
{
JTextField textInput;
JTextArea textShow;
public void setJTextField (JTextField text){
textInput=text;
}
public void setJTextArea(JTextArea area){
textShow=area;
}
public void actionPerformed(ActionEvent e){
String str=textInput.getText();
textShow.append(str+"的长度:"+str.length()+"\n");
}
}