How refresh JProgressBar display ?

Question

I use a JProgressBar in my program but the display of it is never refresh even if I use updateUI method.
Do you know a way to have a real refresh of my display ?

Answer 1

you need to implement a model and associate it to the GUI:
take a look in the BoundedRangeModel class....
http://java.sun.com/docs/books/tutorial/uiswing/components/progress.html
the code bellow is a large one I used in a class about Model-View-Controller paradigm.. It is big, but I hope it help you...
import javax.swing.*;
import java.util.*;
import java.awt.*;
import javax.swing.event.*;
* This test class demonstrates the control-model-view programing paradigm
* @version 1.0 beta
* @author Felipe Gaucho
* @date september 2000
public class CMV
     Model model = null;
     static public void main(String[] args)
          try
               new CMV(Integer.parseInt(args[0]));
          catch(Exception error)
               new CMV(1000); // Default test value
     CMV(int limit)
          // Creates a data model
          model = new Model(limit);
          // Set the model observers
          model.addObserver(new SwingView(model));
          model.addObserver(new AwtView());
          // Set a controller to the model
          Control controller = new Control(model);
// VIEW
class SwingView extends JFrame implements Observer
     JProgressBar progress = null;
     JSlider slider = null;
     SwingView(Model model)
          super("Swing Viewer");
          try
               //UIManager.setLookAndFeel("com.sun.java.swing.plaf.motif.MotifLookAndFeel");
               //UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");
               //UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
          catch(Exception error)
          // Creates a new progress bar indicating the model status
          progress = new JProgressBar(model);
          progress.setStringPainted(true);
          // Creates a new slider providing an interactive way of model data modifying
          slider = new JSlider(model);
          slider.setVisible(false);
          // Swing layout mounting
          getContentPane().setLayout(new BorderLayout(2,2));
          getContentPane().add(new JLabel("Swing do it better!", JLabel.CENTER), BorderLayout.CENTER);
          getContentPane().add(progress, BorderLayout.SOUTH);
          getContentPane().add(slider, BorderLayout.NORTH);
          setSize(250,100);
          setLocation(50,50);
          setVisible(true);
     public void update(Observable model, Object component)
          if( ! slider.isVisible() && ((Model)model).getValue() == ((Model)model).getMaximum())
               slider.setVisible(true);
          progress.repaint();
// VIEW
class AwtView extends Frame implements Observer
     Label valueInfo = new Label("", Label.CENTER);
     AwtView()
          // Set title and layout type
          super("Awt Viewer");
          setLayout(new BorderLayout());
          // Set the layout components
          add(new Label("Awt use light weight components!", Label.CENTER), BorderLayout.CENTER);
          valueInfo.setFont(new Font("Serif",Font.BOLD+Font.ITALIC,32));
          add(valueInfo, BorderLayout.SOUTH);
          // Display it
          setSize(250,100);
          setLocation(350,50);
          setVisible(true);
     public void update(Observable model, Object component)
          valueInfo.setText(((Model)model).getValue() + " / " + ((Model)model).getMaximum());
// MODEL
class Model extends Observable implements BoundedRangeModel
     private int value = 0;
     private int minimum = 0;
     private int maximum = 0;
     Model(int maximum)
          this(0, maximum, 0);
     Model(int minimum, int maximum, int initialValue)
          this.minimum = minimum;
          this.maximum = maximum;
          this.value = initialValue;
     public void addChangeListener(ChangeListener x) {}
     public int getExtent() {return 1;}
     public int getMaximum() {return maximum;}
     public int getMinimum() {return minimum;}
     public int getValue() {return value;}
     public boolean getValueIsAdjusting (){return true;}
     public void removeChangeListener(ChangeListener x){}
     public void setExtent(int newExtent) {}
     public void setMaximum(int newMaximum) {}
     public void setMinimum(int newMinimum) {}
     public void setRangeProperties(int value, int extent, int min, int max, boolean adjusting) {}
     public void setValue(int value)
          this.value = value;
          setChanged();
          notifyObservers();  // <== Notify the observers about the model data changing
     public void setValueIsAdjusting(boolean b) {}
// CONTROL
class Control
     private Model model = null;
     Control(Model model)
          this.model = model;
          int limit = model.getMaximum();
          for(int i=0; i<limit; i++)
               model.setValue((model.getValue())+1);
}