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Thread: Help me find my misstake. Only 80 rows of code.

  1. #1
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    Unhappy Help me find my misstake. Only 80 rows of code.

    Hi, I started to follow some tutorial on YouTube but now I'm really stuck. The window pups up but the little box that's suppose to follow my mouse doesn't show. And the colors doesn't change when click.
    Thanks for the help, I appreciate it!
    package mouse;
     
    import java.awt.*;
    import java.awt.event.MouseEvent;
    import java.awt.event.MouseMotionListener;
     
    import javax.swing.JFrame;
     
    public class Mouse extends JFrame implements MouseMotionListener {
     
    	private Image dpImage;
    	private Graphics dbg;
     
    	boolean mouseDragged;
     
    	int mx, my;
     
    	public Mouse(){
    		setSize (400, 300);
    		setVisible(true);
    		setResizable(false);
    		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    		addMouseMotionListener(this);
     
     
    	}
     
     
    	@Override
    	public void paint(Graphics g){
    		dpImage = createImage(getWidth(), getHeight());
    		dbg = dpImage.getGraphics();
    		paintComponents(dbg);
    		g.drawImage(dpImage, 0, 0, this);
    	}
     
    	public void paintComponet(Graphics g) {
    		if(mouseDragged){
    			g.setColor(Color.DARK_GRAY);
    			g.fillRect(0, 0, getWidth(), getHeight());
    			g.setColor(Color.LIGHT_GRAY);
    			g.fillRect(mx, my, 20, 20);
    		}
    		else{
    			g.setColor(Color.LIGHT_GRAY);
    			g.fillRect(0, 0, getWidth(), getHeight());
    			g.setColor(Color.DARK_GRAY);
    			g.fillRect(mx, my, 20, 20);
    		}
     
     
    		repaint();
    	}
     
    	public static void main (String[] args){
    		Mouse mouse = new Mouse();
    	}
     
     
    	@Override
    	public void mouseDragged(MouseEvent e) {
    		mx = e.getX()-10;
    		my = e.getY()-10;
     
    		mouseDragged = true;
     
    		e.consume();
    	}
     
     
    	@Override
    	public void mouseMoved(MouseEvent e) {
    		mx = e.getX();
    		my = e.getY();
     
    		mouseDragged = false;
     
    		e.consume();
    	}
    }


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Help me find my misstake. Only 80 rows of code.

    Several problems:
    You should NOT override both paint() and paintComponent().
    You should NOT override either method of the JFrame class. NOTE: JFrame doesn't have a paintComponent() method.
    If you want to do custom drawing, create a class that extends the JPanel class, override its paintComponent() method and add an instance of that class to the JFrame object.
    The repaint() method should NOT be called from a paint method.
    Why is there a call to the paintComponents() method?

    Just noticed that the method's name is close to paintComponent() but different. Why use a name that can cause confusion. It's less confusing if you Give your method's unique names.

    To see if and when the mouse listeners are called, add a call to the println() method to them that prints a message when they are called.
    Move the call to repaint() to the listener methods.
    Last edited by Norm; March 29th, 2013 at 04:47 PM. Reason: Added note re calling repaint from listener
    If you don't understand my answer, don't ignore it, ask a question.

  3. The Following 2 Users Say Thank You to Norm For This Useful Post:

    curmudgeon (March 29th, 2013), Zexus (March 29th, 2013)

  4. #3
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    Default Re: Help me find my misstake. Only 80 rows of code.

    Okay thanks for the help mate. If you want and have time could you help me find find some tutorials and tell me WHY I should not do these things that you said?

    Once again, Thanks!

  5. #4
    Super Moderator Norm's Avatar
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    Default Re: Help me find my misstake. Only 80 rows of code.

    See the tutorial on custom painting: Lesson: Performing Custom Painting (The Java™ Tutorials > Creating a GUI With JFC/Swing)
    If you don't understand my answer, don't ignore it, ask a question.

  6. The Following User Says Thank You to Norm For This Useful Post:

    Zexus (March 29th, 2013)

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