Troubles with JPanel

Question

I'am trying to do a simple code that will make my rectangles bigger. So, I decided to do one thread, that will update rectangle's widght, it looks like this:

class CoolThread extends Thread {
MyPanel MLP;

public CoolThread(MyPanel Panel1) {
    MLP = Panel1;
}

@Override
public void run() {
    super.run();   
    while (true) {
        for (int i = 0; i < MLP.arrForRect.size() - 1; i++) {
            MLP.arrForRect.get(i).animation();
            MLP.repaint();
        }}}}

In debugger it looks fine, width changing its numbers perfectly. So, where i did wrong, guys? Now my problem is the weird input lag when i click on the window. Edited for Ctrl+c, CTRL+v compiling.

 public class PaintWindow {
void createGUI() {
    JFrame f = new JFrame("My Canvas");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.add(new MyPanel());
    f.setSize(800, 400);
    f.setResizable(false);
    f.setVisible(true);
    f.setLocationRelativeTo(null);
}

 }
class MyPanel extends JPanel {
public Point mousePos;
Timer animTimer;
ArrayList<ObjRectangle> arrForRect = new ArrayList<ObjRectangle>();
ObjRectangle ObjRect1;

public MyPanel() {
    final ActionListener taskPerformer=new ActionListener() {
        @Override
        public void actionPerformed(ActionEvent e) {
            for (int i=0;i<arrForRect.size()-1;i++){
                arrForRect.get(i).animation();
                repaint();
            }
        }
    };

    addMouseListener(new MouseAdapter() {
        @Override
        public void mouseClicked(MouseEvent e) {
            super.mouseClicked(e);    
            System.out.println(getMousePosition());
            animTimer=new Timer(100,taskPerformer);
            animTimer.start();
            mousePos = getMousePosition();
            ObjRect1 = new ObjRectangle();
            arrForRect.add(ObjRect1);
            repaint();
        }
    });

}

public void paintComponent(Graphics g) {
    super.paintComponent(g);
    arrForRect.get(arrForRect.size() - 1).drawObject(mousePos);
    for (int i = 0; i < arrForRect.size() - 1; i++) {
        arrForRect.get(i).paintSquare(g);
    }
}

 class ObjRectangle extends JPanel  {
int x, y = 0;
int width = 50;
int height = 20;


public void drawObject(Point coordinates) {
    this.x = coordinates.x;
    this.y = coordinates.y;
}

public void animation() {
   width++;
}

public void paintSquare(Graphics g) {
    g.setColor(Color.BLACK);
    g.drawRect(x, y, width, height);
}
 }
 public class MainClass {
PaintWindow window1= new PaintWindow();
    window1.createGUI();
}

}

Answer 1

In debugger it looks fine, width changing its numbers perfectly. So, where i did wrong, guys?

• all events in Swing GUI must be done on EDT, more read in Concurency in Swing

• MLP.repaint(); could not notify EDT in Java7

• use Swing Timer instead of plain Thread

• override getPreferrredSize for JPanel in the class ObjRectangle extends JPanel implements GraphicObject {

• for better help sooent post an SSCCE, short, runnable, compilable

  ---

EDIT

• don't to call repaint(); in paintComponent(), because, then paintComponent() can be intialized again from itself, its can created endless, unmanagable loop, addept for Task Manager