Java 中 WindowListener 接口的重要性是什么?
处理 **WindowEvent** 的类需要实现此接口,并且可以使用 **addWindowListener()** 方法将此类的对象注册到组件。
WindowListener 接口的方法
**WindowListener** 接口定义了 7 种处理窗口事件的方法
- **void windowActivated(WindowEvent we)** − 当窗口被激活时调用。
- **void windowDeactivated(WindowEvent we)** − 当窗口被取消激活时调用。
- **void windowOpened(WindowEvent we)** − 当窗口打开时调用。
- **void windowClosed(WindowEvent we)** − 当窗口关闭时调用。
- **void windowClosing(WindowEvent we)** − 当窗口正在关闭时调用。
- **void windowIconified(WindowEvent we)** − 当窗口最小化时调用。
- **void windowDeiconfied(WindowEvent we)** − 当窗口恢复时调用。
语法
public interface WindowListener extends EventListener
示例
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class WindowListenerTest extends JFrame implements WindowListener {
JLabel l1,l2;
JTextField t1;
JPasswordField p1;
JButton b1;
public WindowListenerTest() {
super("WindowListener Test");
setLayout(new GridLayout(3,2));
l1 = new JLabel("Name");
l2 = new JLabel("Password");
t1 = new JTextField(10);
p1 = new JPasswordField(10);
b1 = new JButton("Send");
add(l1);
add(t1);
add(l2);
add(p1);
add(b1);
addWindowListener(this);
}
public static void main(String args[]) {
WindowListenerTest wlt = new WindowListenerTest();
wlt.setSize(375, 250);
wlt.setResizable(false);
wlt.setLocationRelativeTo(null);
wlt.setVisible(true);
}
public void windowClosing(WindowEvent we) {
this.setVisible(false);
System.exit(0);
}
public void windowActivated(WindowEvent we) {
}
public void windowDeactivated(WindowEvent we) {
}
public void windowOpened(WindowEvent we) {
}
public void windowClosed(WindowEvent we) {
}
public void windowIconified(WindowEvent we) {
}
public void windowDeiconified(WindowEvent we) {
}
}输出
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