drawstringdemo.java

java编程代码

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.BorderLayout;
import java.awt.Graphics;
import java.awt.Color;
import java.awt.Font;

public class DrawStringDemo extends JFrame 
                            implements ActionListener
{
    public static final int WIDTH = 350;
    public static final int HEIGHT = 200;
    public static final int X_START = 20;
    public static final int Y_START = 100;
    public static final int POINT_SIZE = 24;

    private String theText = "Push the button.";
    private Color penColor = Color.BLACK;
    private Font fontObject = 
                      new Font("SansSerif", Font.PLAIN, POINT_SIZE);

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


    public DrawStringDemo( )
    {
        setSize(WIDTH, HEIGHT);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("drawString Demonstration");

        getContentPane( ).setBackground(Color.WHITE);
        setLayout(new BorderLayout( ));

        JPanel buttonPanel = new JPanel( );
        buttonPanel.setBackground(Color.ORANGE);
        buttonPanel.setLayout(new BorderLayout( ));

        JButton theButton = new JButton("The Button"); 
        theButton.addActionListener(this);


        buttonPanel.add(theButton, BorderLayout.CENTER);


        add(buttonPanel, BorderLayout.SOUTH);
    }


    public void paint(Graphics g)
    {
        super.paint(g);
        g.setFont(fontObject);
        g.setColor(penColor);
        g.drawString(theText, X_START, Y_START);
    }


    public void actionPerformed(ActionEvent e) 
    {
        penColor = Color.RED;
        fontObject = 
               new Font("Serif", Font.BOLD|Font.ITALIC, POINT_SIZE);
        theText = "Thank you. I needed that.";


        repaint( );
    }
}