<pre><codeclass="language-java">public class drawingWindow extends JPanel {
JTextField field;
JButton draw;
DrawingPanel drawingPanel;
public drawingWindow() {
// Each new component would be vertically stacked upon each other
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
JPanel swingSTuff = new JPanel();
// Add things to the screen
draw = new JButton("Draw");
field = new JTextField();
swingStuff.add(field);
swingStuff.add(draw)
// Add the drawing panel onto the screen
drawingPanel = new DrawingPanel(200, 400);
add(drawingPanel);
// Activate the listener if the button was pressed
draw.addActionListener(new Listener());
}
// Add the listener to respond to events
private class listener implements ActionListener {
public void actionPerformed(ActionEvent event) {
if (event.getSource() == draw) {
drawingPanel.setFlag(1);
// Repaints the screen so the oval can appear
drawingPanel.repaint();
}
}
}
// Create the draw panel so we can add it to the screen
private class DrawingPanel extends JPanel {
private int width, height;
DrawingPanel(int width, int height) {
this.width = width;
this.height = height;
setPreferredSize(new Dimension(width, height));
}
public void setFlag(int flag) {
this.flag = flag;
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
// Every time the flag is set, draw an oval at a random location and color
if (flag == 1) {
Random rand = new Random();
int x = rand.nextInt(width);
int y = rand.nextInt(height);
g.setColor(Color.RED);
g.fillOval(x, y, 20, 30);
}
}
}
}</code></pre>
<p>There are a myriad of different methods you can use. </p>
<pre><codeclass="language-java">// Assume width, height, y, x, etc are defined above
public void paintComponent(Graphics g) {
//....
g.dispose(); // Flushes the graphics buffer
}</code></pre>
<p>You have the traditional fill and draw methods. Fill creates the shape shaded in with a color. Draw creates an outline of the shape.</p>
<pre><codeclass="language-java">
// ...
g.fillRect(x ,y, width, height);
g.drawRect(x, y, width, height);
g.fillOval(x, y, width, height);
g.drawOval(x, y, width, height);
//g.drawPoly(parematers...);
//g.fillPoly(parameters...);
g.drawArc(x, y, width, height, startingAngle, sweepingAngle);
g.fillArc(x, y, width, height, startingAngle, sweepingAngle);</code></pre>
<p>You can also create complex shapes like a polygon. When adding points, you need to make sure you add them Clockwise or Counterclockwise (but NOT both)</p>
<pre><codeclass="language-java"> Polygon tri = new Polygon();
tri.addPoint(150, 10);
tri.addPoint(175, 100);
tri.addPoint(125, 100);
// Add points clockwise or counterclockwise (NOT BOTH)</code></pre>
