Displaying panels...

[celine mcgowan]

Hi Everyone,

Sorry to bother you all again. I am again having probs with an accursed LED panel thingy. I have finally got it to compile etc - thanks everyone for your help with that (see post here:Non-default constructor problem)! Anyway, I have a method which updates the gifs which are in an LEDPanel:

public JPanel updateLED( int bin )
    {
        //point the labels to the gifs.
        
        //if zero-eth bit (top bar) & 1 is 0, top bar is on.
        if( ( bin & 1 ) == 0)
        {
            top.setIcon( new ImageIcon( "horiz_lit.gif" ) );
        }
        else
        {
            top.setIcon(new ImageIcon("horiz_unlit.gif"));
        }
        //if 6th bit (middle bar) & 1 is 0, middle bar is on.
        if( ( bin & 64 ) == 0)
        {
            middle.setIcon(new ImageIcon("horiz_lit.gif"));
        }
        else
        {
            middle.setIcon(new ImageIcon("horiz_unlit.gif"));
        }
        //if 3rd bit (bottom bar) & 1 is 0, bottom bar is on.
        if( ( bin & 8 ) ==0 )
        {
            bottom.setIcon(new ImageIcon("horiz_lit.gif"));
        }
        else
        {
            bottom.setIcon(new ImageIcon("horiz_unlit.gif"));
        }
        //if 5th bit (top left vertical bar) & 1 is 0, topLeft bar is on.
        if( ( bin & 32 ) == 0 )
        {
            topLeft.setIcon(new ImageIcon("vertical_lit.gif"));
        }
        else
        {
            topLeft.setIcon(new ImageIcon("vertical_unlit.gif"));
        }
        //if 1st bit (top Right Vertical bar) & 1 is 0, topRight bar is on.
        if( ( bin & 2 ) == 0 )
        {
            topRight.setIcon(new ImageIcon("vertical_lit.gif"));
        }
        else
        {
            topRight.setIcon(new ImageIcon("vertical_unlit.gif"));
        }
        //if 4th bit (bottom left vertical bar) & 1 is 0, bottomLeft bar is on.
        if( ( bin & 16 ) ==0 )
        {
            bottomLeft.setIcon(new ImageIcon("vertical_lit.gif"));
        }
        else
        {
            bottomLeft.setIcon(new ImageIcon("vertical_unlit.gif"));
        }
        //if 2nd bit (bottom Right Vertical bar) & 1 is 0, bottomRight bar is on.
        if( ( bin & 4 ) ==0)
        {
            bottomRight.setIcon(new ImageIcon("vertical_lit.gif"));
        }
        else
        {
            bottomRight.setIcon(new ImageIcon("vertical_unlit.gif"));
        }
        
        //Set up a panel to put the gifs in.
        //Top Panel: Makes a 'Square' of the gifs
        JPanel topPanel = new JPanel();
        topPanel.setLayout(new BorderLayout());
        
        topPanel.add(top, BorderLayout.NORTH); //add the top bar of led 
        topPanel.add(topLeft, BorderLayout.WEST); //add top left vertical bar  
        topPanel.add(topRight, BorderLayout.EAST); //add top right vertical bar
        topPanel.add(middle, BorderLayout.SOUTH); //add 'middle' horizontal bar
        
        //Bottom Panel: Makes a topless square
        JPanel bottomPanel = new JPanel();
        bottomPanel.setLayout(new BorderLayout());
        
        bottomPanel.add(bottomLeft, BorderLayout.WEST);
        bottomPanel.add(bottomRight, BorderLayout.EAST);
        bottomPanel.add(bottom, BorderLayout.SOUTH);
        
        //Add top & bottom panels to LEDPanel
        JPanel ledPanel = new JPanel();
        ledPanel.setLayout( new BorderLayout());
        ledPanel.add( topPanel, BorderLayout.NORTH );
        ledPanel.add( bottomPanel, BorderLayout.CENTER );
        
        //add the whole panel to the window
        setLayout( new BorderLayout() );
        add( ledPanel );
        setBorder( BorderFactory.createEmptyBorder( 20, 20, 20, 20 ) );
        
        return ledPanel;
    }  

I am calling the above method 8 times in another class in order to output 8 LED displays. Here's that code:

public class LEDPanel extends LED
{
    LED ledZero = new LED();
    LED ledOne = new LED();
    LED ledTwo = new LED();
    LED ledThree = new LED();
    LED ledFour = new LED();
    LED ledFive = new LED();
    LED ledSix = new LED();
    LED ledSeven = new LED();
    
    public LEDPanel()
    {        
        JPanel ledPanel0 = updateLED( 9 );
        
        JPanel ledPanel1 = updateLED( 6 );
        
        JPanel ledPanel2 = updateLED( 71 );
        
        JPanel ledPanel3 = updateLED( 71 );
        
        JPanel ledPanel4 = updateLED( 64 );
        
        JPanel ledPanel5 = updateLED( 127 );
        
        JPanel ledPanel6 = updateLED( 127 );
        
        JPanel ledPanel7 = updateLED( 127 );
        
        //add all LED's to the main panel:
        JPanel mainPanel = new JPanel();
        mainPanel.add( ledPanel0 );
        mainPanel.add( ledPanel1 );
        mainPanel.add( ledPanel2 );
        mainPanel.add( ledPanel3 );
        mainPanel.add( ledPanel4 );
        mainPanel.add( ledPanel5 );
        mainPanel.add( ledPanel6 );
        mainPanel.add( ledPanel7 );
        add(mainPanel);
    }
    
    public static void main( String [] args )
    {
        JFrame frame = new JFrame( "LED Panel" );
        frame.addWindowListener( new WindowAdapter()
        {
            public void windowClosing(WindowEvent e)
            {
                System.exit(0);
            }
        });
        
        frame.setContentPane( new LEDPanel( ) );
        frame.pack();
        frame.setVisible( true );
    }
}  

When i run LEDPanel, i only get one panel displaying. It seems to be the last panel, but i'm not sure! Does anyone know why there is only one LED displaying, and not all 8?

Thanks again all.
Celine

[Julian Kennedy]

Read up about layout managers in your Swing reference. You need to use one.

Jules

[Michael Dunn]

If it's the size, possible this line
setBorder( BorderFactory.createEmptyBorder( 20, 20, 20, 20 ) );

should be
ledPanel.setBorder( BorderFactory.createEmptyBorder( 20, 20, 20, 20 ) );

[celine mcgowan]

Hi All,

Thanks for your help. I have changed the code in LEDPanel so that there is a GridLayout manager (one row, eight columns) on the main Panel:

//add all LED's to the main panel:
        JPanel mainPanel = new JPanel( new GridLayout( 1, 8 ) );
        mainPanel.add( ledPanel0 );
        mainPanel.add( ledPanel1 );
        mainPanel.add( ledPanel2 );
        mainPanel.add( ledPanel3 );
        mainPanel.add( ledPanel4 );
        mainPanel.add( ledPanel5 );
        mainPanel.add( ledPanel6 );
        mainPanel.add( ledPanel7 );
        add(mainPanel);  

This still only outputs one LED... Am i doing something really silly?

Thanks,
Celine

[Dirk Schreckmann]

Moving this to the Swing / JFC / AWT forum...

[clio katz]

i can't really tell from the code fragments, but it looks
like you're adding each LEDPanel (twice) and doing some
layout stuff in _updateLED:

CODE FRAGMENT...
//add the whole panel to the window
setLayout( new BorderLayout() );
add( ledPanel );
setBorder( BorderFactory.createEmptyBorder( 20, 20, 20, 20 ) );


Is there another 'shadow' window that you also populate
when you invoke main?

if not, it s.b. ok to remove/relocate this code.


My only other comment would be that your _updateLED method
also appears to allocate the *same* JLabel set (i'm guessing
they are JLabels...) to each panel. As I recall, Swing
won't like this. If you continue to have problems, try
replacing the .setIcon calls with new JLabel eg

eg replace

bottomRight.setIcon(new ImageIcon("vertical_lit.gif"));

with something like

bottomRight = new JLabel(new ImageIcon("vertical_lit.gif"));


good luck!

[clio katz]

ok celine,
i looked at your other post with more of your code and i believe i see what you're asking ...

i think my previous response pretty much still applies: you have a couple of places where you are instantiating some objs you don't use, and the updateLED references LED obj that haven't been properly initialized ...

Last comment would be to check your code to see where you are making changes to the LED visual model - probably only want to do things like layout changes once: at init time etc

i couldn't resist re-organizing your code into one LEDPanel class:

import java.awt.BorderLayout;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import javax.swing.BorderFactory;
import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import java.util.Vector;
 
/** LEDPanel represents a generic panel of 
* any number of individual LED panes. */
public class LEDPanel extends JPanel {
 
    static final ImageIcon horiz_on = new ImageIcon("horiz_lit.gif");
    static final ImageIcon horiz_off = new ImageIcon("horiz_unlit.gif");
    static final ImageIcon vert_on = new ImageIcon("vertical_lit.gif");
    static final ImageIcon vert_off = new ImageIcon("vertical_unlit.gif");
    
    Vector vectLED = new Vector();
    
    public LEDPanel() {
        
        // set default orientation
        setLayoutAxis( BoxLayout.X_AXIS );
        
    }
    
    /** Sets this panel's layout axis.
    * @param axis must be a valid BoxLayout axis! */
    public void setLayoutAxis(int axis) {
        
        this.setLayout(new BoxLayout(this, axis));
    }
    
    /** Appends a set of LEDs to the main panel */
    public void appendLEDGroup(int bin) {
        JPanel panel = generateLEDPane( bin );
        vectLED.addElement( panel );
        this.add( panel );
    }
 
    /** Sets a given LED group.
    * @param groupNum is the 0-based index
    */
    public void setLEDGroup(int groupNum, int bin) {
        
        if ( groupNum > vectLED.size() ) {
            return;
        }
        
        if ( groupNum == vectLED.size() ) {
            appendLEDGroup(bin);
            return;
        }
        
        vectLED.set( groupNum, generateLEDPane( bin ) );
        
        this.setVisible( false );
        
        this.removeAll();
        
        for (int i = 0; i < vectLED.size(); i++) {
            this.add( (JPanel) vectLED.get( i ) );
        }
        
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                setVisible( true );
            }
        });
        
    }
    
    private JPanel generateLEDPane( int bin ) {
 
        // Assign label images
        
        //Top Horizontal
        JLabel top = new JLabel( getHLEDIcon(bin & 1) );
 
        //Middle Horizontal
        JLabel middle = new JLabel( getHLEDIcon(bin & 64) );
                
        //Bottom Horizontal
        JLabel bottom = new JLabel( getHLEDIcon(bin & 8) );
        
        
        //Top Left Vertical    
        JLabel topLeft = new JLabel( getVLEDIcon(bin & 32) );
            
        //Top Right Vertical
        JLabel topRight = new JLabel( getVLEDIcon(bin & 2) );
        
        //Bottom Left Vertical
        JLabel bottomLeft = new JLabel( getVLEDIcon(bin & 16) );
        
        //Bottom Right Vertical    
        JLabel bottomRight = new JLabel( getVLEDIcon(bin & 4) );
 
           
        JPanel topPanel = new JPanel();
        topPanel.setLayout(new BorderLayout());
            
        //add the top bar of led
        topPanel.add(top, BorderLayout.NORTH);
            
        //add top left vertical bar
        topPanel.add(topLeft, BorderLayout.WEST);
        
        //add top right vertical bar
        topPanel.add(topRight, BorderLayout.EAST);
        
        //add 'middle' horizontal bar
        topPanel.add(middle, BorderLayout.SOUTH);
        
 
        //Bottom Panel: Makes a topless square        
        JPanel bottomPanel = new JPanel();
        bottomPanel.setLayout(new BorderLayout());
        bottomPanel.add(bottomLeft, BorderLayout.WEST);
        bottomPanel.add(bottomRight, BorderLayout.EAST);
        bottomPanel.add(bottom, BorderLayout.SOUTH);
 
        //Add top & bottom panels to LEDPanel
        JPanel ledPanel = new JPanel();
        ledPanel.setLayout( new BorderLayout());
        ledPanel.add( topPanel, BorderLayout.NORTH );
        ledPanel.add( bottomPanel, BorderLayout.CENTER );
        
        ledPanel.setBorder( BorderFactory.createEmptyBorder( 20, 20, 20, 20 ) );
        
        return ledPanel;    
    }
    
    private ImageIcon getHLEDIcon(int swit) {
        return (swit == 0?  horiz_on : horiz_off);
    }
    
    private ImageIcon getVLEDIcon(int swit) {
        return (swit == 0?  vert_on : vert_off);
    }
 
    /** Tests a panel of 8 LEDs */
    public static void main( String [] args )    {
            
        JFrame frame = new JFrame( "LED Panel" );
 
        LEDPanel ledPanel = new LEDPanel();
 
        ledPanel.setLayoutAxis(BoxLayout.X_AXIS);
        
        ledPanel.appendLEDGroup(9);
        ledPanel.appendLEDGroup(6);
        ledPanel.appendLEDGroup(71);
        ledPanel.appendLEDGroup(71);
        ledPanel.appendLEDGroup(64);
        ledPanel.appendLEDGroup(127);
        ledPanel.appendLEDGroup(127);
        ledPanel.appendLEDGroup(127);
 
        frame.setContentPane( ledPanel );
        frame.pack();
        frame.setVisible( true );
        
        frame.addWindowListener( new WindowAdapter() {            
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
            
        // to test - update the last LED
        // after 3 seconds
        try {
            Thread.sleep(3000);
            ledPanel.setLEDGroup( 7, 9 );
        } catch (InterruptedException e) {}
    }
                
}

hth

[celine mcgowan]

Hi Clio,

You're a lifesaver! I changed "setIcon" to "new JLabel( new ImageIcon..." & took out the panel formatting stuff from the updateLED method as you suggested and it works!!! Makes sense i guess - how can you reset an icon you haven't initialised in the first place. I won't forget this lesson in a hurry!!! Thank you so much for your help & for giving so much of your valuable time to do so.

I have saved the code you posted which is a much more elegant solution to this problem - thanks again. I'm still very much a newbie though & i don't totally understand what's happening there, but i'm gonna spend a bit of time looking at it & running it etc so that i'll understand it by this evening.

Gratefully yours,
Celine

[clio katz]

bravo to you for your hard work and persistence, Celine! i myself learn better by example than by instruction, and so i have benefitted from the wealth of java examples on the web. i'm glad to give back when i can.

thank you for your feedback - 99% of the time i never hear anything so i don't know if i'm helping or harming ... it's nice to hear back, and nicer to have actually helped for a change:-)

[celine mcgowan]

No need to be modest Clio! I get the feeling you've helped many people before me!!!

Thanks again for your time...
Celine