[java]ActionEvent事件：获取输入字符串的长度

代码：

Example9_7.javapublic 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.javaimport 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.javaimport javax.swing.*;import java.awt.event.*;interface MyCommandListener extends ActionListener{public void setJTextField(JTextField text);public void setJTextArea(JTextArea area);}PoliceListen.javaimport 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");}}

运行截图：