For a hw assignment, we were supposed
to create a custom button
to get familiar with swing and responding
to events. We were also
to make this button an event source which confuses me. I have an ArrayList
to keep track of listeners that would register
to listen
to my CustomButton. What I am getting confused on is how
to notify the listeners. My teacher hinted at having a notify and overriding actionPerformed which I tried doing, but then I wasn't sure how
to create an ActionEvent
object looking at the constructor documentation. The source, id,
string all confuses me. Any help would be appreciated. Thanks!
code:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.util.List;
import java.util.ArrayList;
public class CustomButton
{
public static void main(String[] args)
{
EventQueue.invokeLater(new Runnable()
{
public void run()
{
CustomButtonFrame frame = new CustomButtonFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
});
}
public void addActionListener(ActionListener al)
{
listenerList.add(al);
}
public void removeActionListener(ActionListener al)
{
listenerList.remove(al);
}
public void actionPerformed(ActionEvent e)
{
System.out.println("Button Clicked!");
}
private void notifyListeners()
{
ActionEvent event = new ActionEvent(CONFUSED HERE!!!!;
for (ActionListener action : listenerList) {
action.actionPerfomed(event);
}
}
List<ActionListener> listenerList = new ArrayList<ActionListener>();
}
class CustomButtonFrame extends JFrame
{
// constructor for CustomButtonFrame
public CustomButtonFrame()
{
setTitle("Custom Button");
CustomButtonSetup buttonSetup = new CustomButtonSetup();
this.add(buttonSetup);
this.pack();
}
}
class CustomButtonSetup extends JComponent
{
public CustomButtonSetup()
{
ButtonAction buttonClicked = new ButtonAction();
this.addMouseListener(buttonClicked);
}
// because frame includes borders and insets, use this method
public Dimension getPreferredSize()
{
return new Dimension(200, 200);
}
public void paintComponent(Graphics g)
{
Graphics2D g2 = (Graphics2D) g;
// first triangle coords
int x[] = new int[TRIANGLE_SIDES];
int y[] = new int[TRIANGLE_SIDES];
x[0] = 0; y[0] = 0;
x[1] = 200; y[1] = 0;
x[2] = 0; y[2] = 200;
Polygon firstTriangle = new Polygon(x, y, TRIANGLE_SIDES);
// second triangle coords
x[0] = 0; y[0] = 200;
x[1] = 200; y[1] = 200;
x[2] = 200; y[2] = 0;
Polygon secondTriangle = new Polygon(x, y, TRIANGLE_SIDES);
g2.drawPolygon(firstTriangle);
g2.setColor(firstColor);
g2.fillPolygon(firstTriangle);
g2.drawPolygon(secondTriangle);
g2.setColor(secondColor);
g2.fillPolygon(secondTriangle);
// draw rectangle 10 pixels off border
int s1[] = new int[RECT_SIDES];
int s2[] = new int[RECT_SIDES];
s1[0] = 5; s2[0] = 5;
s1[1] = 195; s2[1] = 5;
s1[2] = 195; s2[2] = 195;
s1[3] = 5; s2[3] = 195;
Polygon rectangle = new Polygon(s1, s2, RECT_SIDES);
g2.drawPolygon(rectangle);
g2.setColor(thirdColor);
g2.fillPolygon(rectangle);
}
private class ButtonAction implements MouseListener {
public void mousePressed(MouseEvent e)
{
System.out.println("Click!");
firstColor = Color.GRAY;
secondColor = Color.WHITE;
repaint();
}
public void mouseReleased(MouseEvent e)
{
System.out.println("Released!");
firstColor = Color.WHITE;
secondColor = Color.GRAY;
repaint();
}
public void mouseEntered(MouseEvent e)
{}
public void mouseExited(MouseEvent e)
{}
public void mouseClicked(MouseEvent e)
{}
}
public static final int TRIANGLE_SIDES = 3;
public static final int RECT_SIDES = 4;
private Color firstColor = Color.WHITE;
private Color secondColor = Color.DARK_GRAY;
private Color thirdColor = Color.LIGHT_GRAY;
}
