?? focuseventdemo.java
字號:
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class FocusEventDemo extends JFrame implements FocusListener
{
JButton btnOk,btnCancel;
JLabel lblUserName,lblPassword,lblInfo;
JTextField txtUserName;
JPasswordField pwdPassword;
JPanel pnlMain;
public FocusEventDemo()
{
pnlMain=new JPanel(new GridLayout(3,2));
lblUserName=new JLabel("用戶名:");
txtUserName=new JTextField(8);
txtUserName.addFocusListener(this);
lblPassword=new JLabel("密 碼:");
pwdPassword=new JPasswordField();
pwdPassword.addFocusListener(this);
btnOk=new JButton("確定");
btnOk.addFocusListener(this);
btnCancel=new JButton("取消");
getContentPane().add(pnlMain,"Center");
pnlMain.add(lblUserName);
pnlMain.add(txtUserName);
pnlMain.add(lblPassword);
pnlMain.add(pwdPassword);
pnlMain.add(btnOk);
pnlMain.add(btnCancel);
lblInfo=new JLabel("暫未獲得焦點");
JPanel p2=new JPanel();
getContentPane().add(p2,"South");
p2.add(lblInfo);
setTitle("鼠標事件演示");
setVisible(true);
setSize(250,180);
}
public void focusGained(FocusEvent fe)
{
Object o=fe.getSource();
if(o==txtUserName)
{
lblInfo.setText("請輸入用戶名");
}
else if(o==pwdPassword)
{
lblInfo.setText("請輸入密碼");
}
else
lblInfo.setText("暫未獲得焦點");
}
public void focusLost(FocusEvent fe)
{
Object o=fe.getSource();
if(o==btnOk)
{
lblInfo.setText("確定按鈕失去焦點");
}
if(o==txtUserName)
lblInfo.setText("");
if(o==pwdPassword)
lblInfo.setText("");
}
public static void main (String args[])
{
new FocusEventDemo();
}
}
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