每按一次,按钮上的文字变大一次

java 代码

package example;

import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;

public class RevalidateExample extends JFrame {

    public RevalidateExample( ) {
        super("Revalidation Demo");
        setSize(300,150);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        // Create a single button.
        Font font = new Font("Dialog", Font.PLAIN, 10);
        final JButton b = new JButton("Add");
        b.setFont(font);

        Container c = getContentPane( );
        c.setLayout(new FlowLayout( ));
        c.add(b);

        // Increase the size of the button's font each time it's clicked.
        b.addActionListener(new ActionListener( ) {
          int size = 10;

          public void actionPerformed(ActionEvent ev) {
            b.setFont(new Font("Dialog", Font.PLAIN, ++size));
            b.revalidate( );   // Invalidates the button and validates its root pane
          }
        });
      }

      public static void main(String[] args) {
        RevalidateExample re = new RevalidateExample( );
        re.setVisible(true);
      }

}