Working on a Java GUI/Canvas project [closed]

Answer 1

How I would change your class is like so (note this is pseudo code you'll need to actually implement an action listener for handling button presses)-

public class UI extends JFrame implements ActionListener 
{
ArrayList buttonList = new ArrayList(); 

int x = 0;
int y = 0;
int width = 50;
int height = 50;

public UI()
{
  super("Example Frame");
  setSize(800,600);
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setVisible(true);    

  JPanel mainPanel = new JPanel();

  mainPanel.setLayout(new GridLayout(1,3));

  JPanel buttonPanel = new JPanel();
  buttonPanel.setLayout(new GridLayout(12,1));

  for(int i=1; i<13; i++)
  {   String s = Integer.toString(i);
      buttonPanel.add(new JButton(s));
  }

  add(mainPanel);
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  mainPanel.add(buttonPanel, BorderLayout.CENTER);
}

public void paint(Graphics g){
    super.paint(g);
    g.drawRect(x,y,width,height);
}

onButtonPress(int buttonNumber){
    y = buttonNumber * 10;
    repaint();
}