mypanel.java

这是一个swing的练习

package lab9SecondPackage;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;

public class MyPanel extends JPanel
	implements ActionListener{
	private static final double HEIGHT = 50;
	private static final double WIDTH = 50;
	private static double currentX = 0;
	private static double currentY = 0;
	private Color currentColor = Color.GRAY;
	private JButton blueButton = new JButton("Blue");
	private JButton redButton = new JButton("Red");
	private ArrayList ellipseList = new ArrayList();
	private Graphics2D graphic;
	
	public MyPanel()
	{
		//add mouse adapter
		addMouseListener(new MouseAdapter(){
			public void mouseClicked(MouseEvent e) {
				addEllipse(e.getX(),e.getY());
				showEllipse();
				repaint();
		    }
		});
		
		setLayout(new FlowLayout());
		
		//add button
		add(blueButton);
		add(redButton);
		
		//add action listener
		blueButton.addActionListener(this);
		redButton.addActionListener(this);
	}
	
	public void paintComponent(Graphics g)
	{
		super.paintComponent(g);
		graphic = (Graphics2D)g;
				
		for(int eNum = 0;eNum < ellipseList.size();eNum++)
		{
			graphic.setPaint(((MyEllipse)(ellipseList.get(eNum))).getColor());
			graphic.fill(((MyEllipse)(ellipseList.get(eNum))).getEllipse());
		}
	}
	
	public void addEllipse(double newX,double newY)
	{
		currentX = newX - WIDTH/2;
		currentY = newY + HEIGHT/2;
		MyEllipse ellipse = new MyEllipse(currentX,currentY,HEIGHT,WIDTH,currentColor);
		ellipseList.add(ellipse);
	}

	public void showEllipse()
	{
		for(int eNum = 10; eNum < ellipseList.size(); eNum++)
		{
    		Color tempColor = ((MyEllipse)(ellipseList.get(eNum))).getColor();
    		graphic.setPaint(tempColor);
    		graphic.fill(((MyEllipse)(ellipseList.get(eNum))).getEllipse());
		}
	}
	public void actionPerformed(ActionEvent e)
	{
		Object o = e.getSource();
		if(o == blueButton)
			currentColor = Color.BLUE;
		if(o == redButton)
			currentColor = Color.RED;
	}
}