Question

I’ve looked at several other posts, and I have yet to find a clear answer. I don’t entirely understand the paint method, which is probably my problem, but nowhere can I find a clear explanation. Can someone help me get this one working? The issue is that the paint method is not running. Everything else seems to work fine, but I do not see the oval I tell the program to render in the frame.

import java.awt.Color;
import java.awt.Component;
import java.awt.Frame;
import java.awt.Graphics;

@SuppressWarnings("serial")
public class TestObject extends Component {

    MouseResponder mouseListener = new MouseResponder();            // Creates a new mouse listener.

    WindowResponder windowListener = new WindowResponder();         // Creates a new window listener.

    Frame mainFrame = new Frame();                              // Makes a new frame.

public TestObject() {

    mainFrame.setSize(400,500);                                 // Makes the new frame 400 by 500 in size.

    mainFrame.setLocationRelativeTo(null);                      // Sets the location of the window to center it.

    mainFrame.setTitle("A Test program!");                      // Sets frame label.

    mainFrame.setBackground(new Color(199,199,199));            // Sets the background color of the window.

    mainFrame.addWindowListener(windowListener);                // Adds the window listener so close works.

    mainFrame.addMouseListener(mouseListener);                  // Adds the mouse listener to the frame.

    mainFrame.setVisible(true);                                 // Makes the new frame visible.

    System.out.println("[TestObject] Window" +                  // Prints a console message when main window is launched.
            " configured and launched.");


}

public void paint(Graphics pane) {

    System.out.println("[TestObject] Painting.");

    pane.setColor(Color.BLACK);
    pane.drawOval(10,10,10,10);

}

}

Other Info:

• MouseResponder and WindowResponder are separate functioning classes.

• The TestObject class seen above is called by a main class which
  creates a new TestObject. The frame displays successfully as I
  specify.

Thank you for any help!
-Docithe

Answer 1

paint() is responsible for rendering a component when it is visible.
At least in your code snippet, you did not add the test-component to the frame – thus, it is not displayed and not painted.

public TestObject() {
    //...
    mainFrame.add( this );
    //...
}

This still might not work because your Test Component is 0x0 pixel.
So you also

@Override
getPreferredSize(){
    return new Dimension( 20, 20 );
}