Help with 2-D Drawing

[Deathmonger]

Hi,

I'm trying to create a simple program that allows the user to control the movement of a square. When the user presses up, the square moves up and so on. However, I can't seem to get the square to move. I think I'm missing the concept of calling the correct method that allows me to repaint the square at the new location. I'm sure there is more to it, and I've been trying to figure this out for a couple of months now (on and off.) I don't know what to do, and if someone knows how to get this to work, some advice would be greatly appreciated. Can someone please help me figure out how to get this square to move?

Thanks in advance

Here is the code I'm using:

Code:

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

public class InteractionX {
	
	// Declare all Buttons, Panels, and labels used for testing
	static JFrame frame;
	static Container contain;
	static JButton up;
	static JButton down;
	static JButton left;
	static JButton right;
	static Panel controls;
	static Panel canvasArea;
	static Panel test;
	static Panel holdsBtns;
	static JLabel yTest;
	static JLabel xTest;
	
	// These are the initial coordinates for the square
	static int x = 75;
	static int y = 75;
	
	// Class: InteractXCanvas
	// Description: Used to draw the square and the borders for the canvas.
	static class InteractXCanvas extends Canvas {
		
		public void paint(Graphics g) {
			Dimension d = canvasArea.getSize();
			int lengthCanvas = d.width;
			int heightCanvas = d.height;
			
			g.drawRect(0,0,lengthCanvas-1,heightCanvas-1);
			g.fillRect(x,y,10,10);
		}
	}
	
	// Class: InteractXMovement
	// Description: Holds the logic for controlling movement of the square.
	static class InteractXMovement implements ActionListener {
		
		public void actionPerformed(ActionEvent ae) {
			String whichButton;
			whichButton = ae.getActionCommand();
			InteractXCanvas IXC = new InteractXCanvas();
			
			if(whichButton.equals("Up")) {
				y = y + 5;
				
			}
			if(whichButton.equals("Down")) {
				y = y-5;
				
			}
			if(whichButton.equals("Left")) {
				x = x-5;
				
			}
			if(whichButton.equals("Right")) {
				x = x+5;
				
			}
			yTest.setText("y: " + y);
			xTest.setText("x: " + x);
		}
	}
	
	public static void main(String[] args) {
		
		// Create constructors for the Movement class and Canvas class.
		InteractXMovement IXM = new InteractXMovement();
		InteractXCanvas IXC = new InteractXCanvas();
		
		// Create Buttons used for controlling the square and the labels used for testing.
		frame = new JFrame("Interaction World");
		contain = new Container();
		up = new JButton("Up");
		down = new JButton("Down");
		left = new JButton("Left");
		right = new JButton("Right");
		yTest = new JLabel("y: " + y);
		xTest = new JLabel("x: " + x);
		
		// Create Panels
		controls = new Panel();
		canvasArea = new Panel();
		test = new Panel();
		holdsBtns = new Panel();
		
		// Add the actionListener from class InteractXMovement
		up.addActionListener(IXM);
		down.addActionListener(IXM);
		left.addActionListener(IXM);
		right.addActionListener(IXM);
		
		// Set frame size and canvas size
		frame.setSize(500,500);
		IXC.setSize(200,200);
		contain = frame.getContentPane();
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		
		// Set layout managers
		contain.setLayout(new BorderLayout());
		controls.setLayout(new GridLayout(1,4));
		test.setLayout(new GridLayout(1,2));
		
		// Add buttons and test labels to their panels.  The buttons are
		// attached to the controls panel, and the labels to the test panel
		controls.add(up);
		controls.add(down);
		controls.add(left);
		controls.add(right);
		test.add(yTest);
		test.add(xTest);
		
		holdsBtns.add(controls);
		holdsBtns.add(test);
		
		canvasArea.add(IXC);
		
		frame.add(holdsBtns, BorderLayout.NORTH);
		frame.add(canvasArea, BorderLayout.CENTER);
		
		frame.setVisible(true);
	}
}

[Zosden]

Try this website Linky

[hardwired]

Code:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class InteractionXRx {
    // Declare only what must be exposed as a member
    // variable, ie, whatever requires class scope.
    JLabel yTest;
    JLabel xTest;
    InteractXCanvas IXC;

    // These are the initial coordinates for the square
    int x = 75;
    int y = 75;

    // Class: InteractXCanvas
    // Description: Used to draw the square and the borders for the canvas.
    private class InteractXCanvas extends Canvas {
        public void paint(Graphics g) {
            Dimension d = //canvasArea.getSize();
                          getSize();
            int lengthCanvas = d.width;
            int heightCanvas = d.height;

            g.drawRect(0,0,lengthCanvas-1,heightCanvas-1);
            g.fillRect(x,y,10,10);
        }

        /** Override getPreferredSize method */
        public Dimension getPreferredSize() {
            return new Dimension(200,200);
        }
    }

    // Class: InteractXMovement
    // Description: Holds the logic for controlling movement of the square.
    private class InteractXMovement implements ActionListener {
        public void actionPerformed(ActionEvent ae) {
            String whichButton = ae.getActionCommand();
            // This new instance of InteractXCanvas is not the
            // one you added to your gui. The x,y member variables
            // are used in the one you added to your gui.
//            InteractXCanvas IXC = new InteractXCanvas();

            if(whichButton.equals("Up")) {
                y = y + 5;
            }
            if(whichButton.equals("Down")) {
                y = y-5;
            }
            if(whichButton.equals("Left")) {
                x = x-5;
            }
            if(whichButton.equals("Right")) {
                x = x+5;
            }
            yTest.setText("y: " + y);
            xTest.setText("x: " + x);
            // Ask the view component to show the change:
            IXC.repaint();
        }
    }

    private void showGUI() {
        // Create constructors for the Movement class and Canvas class.
        IXC = new InteractXCanvas();

        // Create Buttons used for controlling the square and
        // the labels used for testing.
        JButton up = new JButton("Up");
        JButton down = new JButton("Down");
        JButton left = new JButton("Left");
        JButton right = new JButton("Right");
        yTest = new JLabel("y: " + y);
        xTest = new JLabel("x: " + x);

        // Create Panels
        Panel controls = new Panel();
        Panel test = new Panel();
        Panel holdsBtns = new Panel();

        // Add the actionListener from class InteractXMovement
        InteractXMovement IXM = new InteractXMovement();
        up.addActionListener(IXM);
        down.addActionListener(IXM);
        left.addActionListener(IXM);
        right.addActionListener(IXM);

        // Set frame size and canvas size
        JFrame frame = new JFrame("Interaction World");
        frame.setSize(500,500);
        // Does no good before gui is realized, ie, after
        // pack or setVisible is called.
        // Better to override getPreferredSize in
        // the InteractXCanvas class.
//        IXC.setSize(200,200);
        Container contain = frame.getContentPane();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        // Set layout managers
        contain.setLayout(new BorderLayout());
        controls.setLayout(new GridLayout(1,4));
        test.setLayout(new GridLayout(1,2));

        // Add buttons and test labels to their panels.  The buttons are
        // attached to the controls panel, and the labels to the test panel
        controls.add(up);
        controls.add(down);
        controls.add(left);
        controls.add(right);
        test.add(yTest);
        test.add(xTest);

        holdsBtns.add(controls);
        holdsBtns.add(test);

        frame.add(holdsBtns, BorderLayout.NORTH);

        // You can show the view/graphic component (IXC)
        // in the center of another Panel:
        Panel canvasArea = new Panel(new GridBagLayout());
        canvasArea.add(IXC, new GridBagConstraints());

        frame.add(canvasArea, BorderLayout.CENTER);

        // or, eliminate the intermediate container (canvasArea)
        // and put IXC in the center section of your BorderLayout:
//        frame.add(IXC, BorderLayout.CENTER);

        frame.setVisible(true);
    }

    public static void main(String[] args) {
        InteractionXRx app = new InteractionXRx();
        app.showGUI();
    }
}

[Deathmonger]

Thanks both for your help. I can already see there is much more that I need to study.

[Fubarable]

You appear to be mixing Swing components (JButtons, and most anything else that starts with "J") and AWT components (Panel, etc...). I strongly advise you against doing this unless you really know what you are doing, in other words unless you are very strong in your Swing and AWT coding. Myself, I'm not yet strong enough. Also, if you haven't done so, you would be well served by going through the Sun Swing graphics tutorials.

Good luck.