How to: call repaint() 4 times from other class.

[Aji Prasetyo]

Hi all,

I have a question about calling repaint() method from other class. The problem is that I can't call repaint() 4 times from other class. The result is always something like this:

trying to repaint() 1 times...
trying to repaint() 2 times...
trying to repaint() 3 times...
trying to repaint() 4 times...
trying to repaint() 5 times...
Actually doing repaint() 5 times...

Below I have included the code I am talking about.

I am sorry for the trouble but thank you beforehand.

package sharepaneltest;
 
import java.awt.Dimension;
import java.awt.Graphics;
import java.lang.reflect.InvocationTargetException;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
 
public class SharePanelTest extends javax.swing.JApplet {
    
    public void init() {
        try {
            java.awt.EventQueue.invokeAndWait(new Runnable() {
                public void run() {
                    initComponents();
                }
            });
        } catch(InterruptedException ex) { ex.printStackTrace();
        } catch(InvocationTargetException ex) { ex.printStackTrace(); }
    }
    
    public void start() {
        
        new Thread(new Rpaint()).start();
    }
    
    // <editor-fold defaultstate="collapsed" desc=" Generated Code">                          
    private void initComponents() {
        int rdius = 0;
        jPanel1 = new ViewControl(rdius);
 
        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 376, Short.MAX_VALUE)
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 280, Short.MAX_VALUE)
        );
 
        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addContainerGap())
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap()
                .addComponent(jPanel1, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                .addContainerGap())
        );
    }// </editor-fold>                        
    
    // Variables declaration - do not modify                     
    private javax.swing.JPanel jPanel1;
    // End of variables declaration                   
}
 
/*----------------------------------------------------------------------------*/
 
class ViewControl extends JPanel {
 
    private static int rdius = 1;
    
    public ViewControl(int rdius) {
        
        this.rdius = rdius;
    }
    
    public void update(Graphics g) {
 
        paintComponent(g);
    }
    
    public void paintComponent(Graphics g) {
        
        super.paintComponent(g);
        
        Dimension d = getSize();
        int xmax = d.width - 1;
        int ymax = d.height - 1;
        int xcntr = xmax / 2;
        int ycntr = ymax / 2;
        double ALPH;
        java.util.List<java.awt.Point> pts = new java.util.ArrayList<java.awt.Point>();
        int[][] arrayTake = new int[681][2];
        
        for(int n = 0; n < 681; n++) {
            ALPH = (double)(n * (2 * Math.PI / 680)) + (Math.PI / 2);
            int xCor = (int)((double)rdius * Math.cos(ALPH));
            int yCor = (int)((double)rdius * Math.sin(ALPH));
            pts.add(new java.awt.Point(xCor, yCor));
            arrayTake[n][0] = xCor;
            arrayTake[n][1] = yCor;
        }
        System.out.println("Actually doing repaint() " + rdius / 500 + " times...");
        for(int i = 0; i < 681; i++) {
            if(i != 340) {
                g.drawOval((pts.get(i).x / 6) + xcntr, (pts.get(i).y / 6) + ycntr, 1, 1);
            } else {
                g.drawLine(xcntr, ycntr, (pts.get(i).x / 6) + xcntr, (pts.get(i).y / 6) + ycntr);
            }
        }
    }
}
 
/*----------------------------------------------------------------------------*/
 
class Rpaint implements Runnable {
 
    private int rdius;
    
    public void run() {
        
        for(int i = 1; i <= 5; i++) {
            rdius = i * 500;
            System.out.println("trying to repaint() " + i + " times...");
            SwingUtilities.invokeLater(new Runnable(){
                public void run(){
                    new ViewControl(rdius).repaint();
                }
            });
        }
    }
}

[Aji Prasetyo]

The problem is that I can't call repaint() 4 times from other class.

I meant 5 times, sorry.

My preferred result would be:

trying to repaint() 1 times...
Actually doing repaint() 1 times...
trying to repaint() 2 times...
Actually doing repaint() 2 times...
trying to repaint() 3 times...
Actually doing repaint() 3 times...
trying to repaint() 4 times...
Actually doing repaint() 4 times...
trying to repaint() 5 times...
Actually doing repaint() 5 times...

Any help would be greatly appreciated.

[Brian Cole]

You seem to be under the impression that each call to repaint() results in a call to paint()/paintComponent().

This is not the case, which is a good thing. In general we like that mulitple calls to repaint() may be coalesced into a single paint()/paintCoponent() call. It keeps our GUIs responsive.

So, why are you trying to do this? (If you are trying to achieve an animation effect, then you probably want to call repaint() from a timer.)

[edit: Looking more closely at your code, I see I may have misjudged your problem. For example, with new ViewControl(rdius).repaint() you are requesting that a newly-instantiated ViewControl object (which is not added to any container) repaint itself. It seems what you really want to do is call myExistingViewControl.repaint(), where myExistingViewControl is a reference to a single ViewControl object that you have already added to some visible container.]
[ October 08, 2007: Message edited by: Brian Cole ]