Java GUIのイベントの傍受と処理
イベントの傍受と処理の根本的な技術は、コールバックです.甲はインタフェースを提供し、乙はインタフェースを実現し、相応の方法を呼び出す.
package com.sinosuperman.driver;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class MainBench {
public static void main(String[] args) {
JFrame frame = new MyFrame();
}
}
class MyFrame extends JFrame {
private static final long serialVersionUID = 1L;
Toolkit tk = Toolkit.getDefaultToolkit();
Dimension d = tk.getScreenSize();
JPanel panel;
public MyFrame() {
panel = new MyPanel();
this.add(panel);
this.setSize((int) d.getWidth() / 2, (int) d.getHeight() / 2);
this.setLocation((int) (d.getWidth() - this.getWidth()) / 2, (int) (d.getHeight() - this.getHeight()) / 2);
this.setResizable(false);
this.setVisible(true);
}
}
class MyPanel extends JPanel implements ActionListener {
private static final long serialVersionUID = 5263963243638550398L;
JButton okBtn;
JButton exitBtn;
public MyPanel() {
this.setLayout(new FlowLayout(FlowLayout.CENTER));
okBtn = new JButton("OK");
exitBtn = new JButton("Exit");
okBtn.addActionListener(this);
exitBtn.addActionListener(this);
this.add(okBtn);
this.add(exitBtn);
}
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
if (source == okBtn) {
JOptionPane.showMessageDialog(null, "You click the OK Button.");
} else {
JOptionPane.showMessageDialog(null, "You click the Exit Button.");
System.exit(0);
}
}
}