paint method causing other components not to show up

Question

I have a simple GUI program I'm trying to get to work. When the user presses the bottom button I'm trying to get some shapes to paint. When I get rid of the if(buttonClicked) in paint() everything shows up fine but paint() seems to be auto-executed and the shapes appear without any button click. When I add surround the paint() body with if(buttonClicked), regardless of how the ButtonHandler class handles it, the rest of my components do not even show up in the frame. I have no idea why this is happening. Test the code with and without the if logic in paint() and you will see what's going on.

 public class GUI extends JFrame {

      //declare components
     Container container;
     JPanel centerPanel, northPanel, southPanel, eastPanel, westPanel, mouseClickPanel;
     JLabel topLabel;
     JTextArea textArea;
     JButton buttonA, buttonB, drawButton;
     boolean buttonClicked;

     public GUI(String title) {

         super(title); // invoke JFrame Constructor

         container = getContentPane();
         container.setLayout(new BorderLayout());

         centerPanel = new JPanel();
         centerPanel.setBackground(Color.CYAN);
         northPanel = new JPanel();
         northPanel.setBackground(Color.GREEN);
         southPanel = new JPanel();
         southPanel.setBackground(Color.MAGENTA);
         eastPanel = new JPanel();
         eastPanel.setBackground(Color.ORANGE);
         westPanel = new JPanel();
         westPanel.setBackground(Color.YELLOW);
         mouseClickPanel = new JPanel();
         mouseClickPanel.setBackground(Color.GRAY);
         mouseClickPanel.setPreferredSize(new Dimension(400, 400));

         topLabel = new JLabel("Press either button to make something happen");
         topLabel.setFont(new Font("Calibri", Font.PLAIN, 16));
         topLabel.setHorizontalAlignment(JLabel.CENTER);

         textArea = new JTextArea(3, 20);
         textArea.setEditable(false);
         buttonA = new JButton("Press Here");
         buttonB = new JButton("Press Here");
         drawButton = new JButton("Press here");

         container.add(centerPanel, BorderLayout.CENTER);
         container.add(northPanel, BorderLayout.NORTH);
         container.add(southPanel, BorderLayout.SOUTH);
         container.add(eastPanel, BorderLayout.EAST);
         container.add(westPanel, BorderLayout.WEST);

         northPanel.add(topLabel, BorderLayout.NORTH);
         centerPanel.add(buttonA);
         centerPanel.add(textArea);
         centerPanel.add(buttonB);
         centerPanel.add(mouseClickPanel);
         centerPanel.add(drawButton);

         buttonClicked = false;
         ButtonHandler buttonHandler = new ButtonHandler(buttonA, drawButton, textArea, buttonClicked);



         buttonA.addActionListener(buttonHandler); // add actionListeners to buttonA and B
         buttonB.addActionListener(buttonHandler);
         drawButton.addActionListener(buttonHandler);

         setSize(525, 600);
         setVisible(true);
     }



     public void paint(Graphics g) {


        if (buttonClicked) {
            super.paint(g);

            g.setColor(Color.RED);
            g.fillOval(150, 150, 50, 50);
            g.draw3DRect(200, 200, 50, 50, true);
        }
     }
 }

Handler class:

 public class ButtonHandler extends JFrame implements ActionListener {

     private JButton buttonA, drawButton;
     private JTextArea textArea;
     boolean buttonClicked;

 public ButtonHandler(JButton buttonA, JButton drawButton, JTextArea textArea, boolean buttonClicked) {
    this.buttonA = buttonA;
    this.textArea = textArea;
    this.drawButton = drawButton;
    this.buttonClicked = buttonClicked;

}

@Override
public void actionPerformed(ActionEvent e) {

    if (e.getSource() == buttonA) {
        textArea.setText(" <- You pressed left button");
    }
    else if (e.getSource() == drawButton) {

        textArea.setText("You pressed button to draw rectangle");
        buttonClicked = true;
        repaint();
    }
    else {
        textArea.setText("You pressed right button ->");
    }
}
}

Answer 1

Take super.paint(g); out of the if statement. Have it as the first line. Otherwise, no painting at all (including the JPanel internals such as background) will happen unless the button is clicked.