Moving Shapes

DrawShapes

package com.angeliquenguyen_le.a6drawshapes;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;

@SuppressWarnings("serial")
public class DrawShapes extends JFrame {
	// Drawing area constants
	public static final int CANVAS_WIDTH = 500;
	public static final int CANVAS_HEIGHT = 300;
	public static final Color CANVAS_BACKGROUND = Color.YELLOW;
	// Set line coordinates (x1, y1 to x2, y2) starting at center
	private int x1 = CANVAS_WIDTH / 4;
	private int y1 = CANVAS_HEIGHT / 4;
	private int rectWidth = CANVAS_WIDTH / 2;
	private int rectHeight = CANVAS_HEIGHT / 2;
	private String[] shapeName = {"Rectangle", "Circle", "Triangle"};
	
	private CanvasDrawArea canvas; // the custom drawing canvas (extends JPanel)
	/** Constructor to set up the GUI */
	public DrawShapes() {
		// Set up a panel for the buttons
		JPanel btnPanel = new JPanel(new FlowLayout());
		JComboBox shapes = new JComboBox(shapeName);
		btnPanel.add(shapes);
		
		JButton btnLeft = new JButton("Move Left ");
		btnPanel.add(btnLeft);
		btnLeft.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				x1 -= 10;
				canvas.repaint();
				requestFocus(); // change the focus to JFrame to receive
								// KeyEvent
			}
		});
		JButton btnRight = new JButton("Move Right");
		btnPanel.add(btnRight);
		btnRight.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				x1 += 10;
				canvas.repaint();
				requestFocus(); // change the focus to JFrame to receive
								// KeyEvent
			}
		});
	
	// Set up a custom drawing JPanel
	canvas = new CanvasDrawArea();
	canvas.setPreferredSize(new Dimension(CANVAS_WIDTH, CANVAS_HEIGHT));
	
	// Add both panels to this JFrame
	
	Container cp = getContentPane();
	cp.setLayout(new BorderLayout());
	cp.add(canvas, BorderLayout.CENTER);
	cp.add(btnPanel, BorderLayout.SOUTH);
	
	// "this" JFrame fires KeyEvent
	addKeyListener(new KeyAdapter() {
		@Override
		public void keyPressed(KeyEvent evt) {
			switch (evt.getKeyCode()) {
			case KeyEvent.VK_LEFT:
				x1 -= 10;
				//x2 -= 10;
				repaint();
				break;
			case KeyEvent.VK_RIGHT:
				x1 += 10;
				//x2 += 10;
				repaint();
				break;
			}//end switch
		}
	});
	
	setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // Handle the CLOSE
	
	// button		
	setTitle("Drawing Shapes: Moving Shapes");
	pack(); // pack all the components in the JFrame
	setVisible(true); // show it
	requestFocus(); // set the focus to JFrame to receive KeyEvent
	}//draw shapes constructor?
	
	/**
	* CanvasDrawArea (inner class) is a JPanel used for custom drawing
	*/
	class CanvasDrawArea extends JPanel {
		public void paintComponent(Graphics rect) {
			super.paintComponent(rect);
			setBackground(CANVAS_BACKGROUND);
			rect.setColor(Color.BLUE);
			rect.fillRect(x1, y1, rectWidth, rectHeight); 
		}//paintComponent method end
	}//CanvasDrawArea class end
}//DrawShapes class end