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Status: Solved
Priority: Medium
Security: Public
Views: 209
Last Modified: 2010-03-31

Why doesn't this work?!?!?

Please see:

================================
import java.awt.*;
import java.awt.event.*;

public class JF1 extends Panel implements ActionListener{

      public JF1(){
            setup();
            position();
      }


      private Button m_switch;
      private Label m_show;
      private int m_type;

      public void setup(){
            m_switch=new Button("Switch");
            m_switch.setActionCommand(m_switch.getLabel());
            m_switch.addActionListener(this);
            m_show=new Label("Thing1");
            m_type=0;
      }

      public void position(){
            removeAll();
            setLayout(new GridBagLayout());
            GridBagConstraints c=new GridBagConstraints();

            c.gridx=0;
            c.gridy=0;
            c.anchor=c.WEST;
            c.insets=new Insets(10,30,0,0);
            add(m_switch, c);

            c.gridx=1;
            add(m_show, c);
      }

      public void actionPerformed(ActionEvent e){
            if(e.getActionCommand().compareTo("Switch")==0){
                  m_type++;
                  if(m_type>1)
                        m_type=0;
                  if(m_type==0)
                        m_show.setText("Thing1");
                  else if(m_type==1)
                        m_show.setText("Thing2");
            }
      }
}
================================

The texts never change, although the m_type change works fine!

Thank you!

Unimatrix_001

Asked: 2004-08-08

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Java

1 Solution

LVL 7

JugglerWCommented: 2004-08-08

I added a main to your code and tried and it runs without problem on my system?
Also note that I simplified your actionPerformed method slightly.

Cide wtih main:

============================
import java.awt.*;
import java.awt.event.*;

public class JF1 extends Panel implements ActionListener{
public static void main(String[] args)
{
Frame f = new Frame();
f.setSize(200,200);
f.add( new JF1() );
f.setVisible(true);
}

public JF1(){
setup();
position();
show();
}

private Button m_switch;
private Label m_show;
private int m_type;

public void setup(){
m_switch=new Button("Switch");
m_switch.setActionCommand(m_switch.getLabel());
m_switch.addActionListener(this);
m_show=new Label("Thing1");
m_type=0;
}

public void position(){
removeAll();
setLayout(new GridBagLayout());
GridBagConstraints c=new GridBagConstraints();

c.gridx=0;
c.gridy=0;
c.anchor=c.WEST;
c.insets=new Insets(10,30,0,0);
add(m_switch, c);

c.gridx=1;
add(m_show, c);
}

public void actionPerformed(ActionEvent e){
if(e.getActionCommand().compareTo("Switch")==0)
{
m_type ^= 1;
m_show.setText(m_type == 0 ? "Thing1" : "Thing2");
}
}

}

============================

LVL 7

JugglerWCommented: 2004-08-08

>Cide wtih main:

should be

Code with main:

LVL 3

Unimatrix_001Author Commented: 2004-08-08

Right...thanks for that Juggler...

LVL 3

Unimatrix_001Author Commented: 2004-08-08

Ah sorry I only noticed your last comment ;)

LVL 7

JugglerWCommented: 2004-08-08

If the app not works on your system you may try:

public void actionPerformed(ActionEvent e){
if(e.getActionCommand().compareTo("Switch")==0)
{
m_type ^= 1;
m_show.setText(m_type == 0 ? "Thing1" : "Thing2");
validate();
}
}

LVL 3

Unimatrix_001Author Commented: 2004-08-08

Why isn't it working on mine! :( :( :(

LVL 3

Unimatrix_001Author Commented: 2004-08-08

Nope still nothing...

LVL 7

JugglerWCommented: 2004-08-08

or:

public void actionPerformed(ActionEvent e){
if(e.getActionCommand().compareTo("Switch")==0)
{
m_type ^= 1;
m_show.setText(m_type == 0 ? "Thing1" : "Thing2");
repaint();
}
}

LVL 3

Unimatrix_001Author Commented: 2004-08-08

Nah...I've put this in:

public void actionPerformed(ActionEvent e){
if(e.getActionCommand().compareTo("Switch")==0)
{
m_type ^= 1;
m_show.setText(m_type == 0 ? "Thing1" : "Thing2");
}
System.out.println(m_show.getText());
}

And it's just not changing at all...

LVL 7

JugglerWCommented: 2004-08-08

Just for a test try this. If this works something with the compare goes wrong???

public void actionPerformed(ActionEvent e)
{
m_type ^= 1;
m_show.setText(m_type == 0 ? "Thing1" : "Thing2");
System.out.println(m_show.getText());
repaint();
}

LVL 7

JugglerWCommented: 2004-08-08

Some more test outputs:

public void actionPerformed(ActionEvent e)
{
System.out.println("ActionCommand is " + e.getActionCommand());
m_type ^= 1; // Note the ^ this is a XOR operator
m_show.setText(m_type == 0 ? "Thing1" : "Thing2");
System.out.println("m_Type = " + m_Type + " text = " + m_show.getText());
repaint();
}

LVL 7

JugglerWCommented: 2004-08-08

To be sure the event is from your switch button you may also use:

public void actionPerformed(ActionEvent e)
{
if ( e.getSource() == m_switch )
{
m_type ^= 1;
m_show.setText(m_type == 0 ? "Thing1" : "Thing2");
System.out.println("m_Type = " + m_type + " text = " + m_show.getText());
repaint();
}
}

and it's faster as the string compare.

LVL 3

Unimatrix_001Author Commented: 2004-08-08

I've already tried that, and it's not even picking up the button then!

Although System.out gave:
show = java.awt.Label[label2,0,0,0x0,invalid,align=left,text=Thing1] text = Thing2

LVL 7

JugglerWCommented: 2004-08-08

Here again the whole program as it works for me. With every press to button the text changes from Thing1 to Thing2. Need some sleep now. CU and Good luck.

import java.awt.*;
import java.awt.event.*;

public class JF1 extends Panel implements ActionListener
{
//~ Instance fields --------------------------------------------------------------------------------------------------------------------

private Button m_switch;
private Label m_show;
private int m_type;

//~ Constructors -----------------------------------------------------------------------------------------------------------------------

public JF1( )
{
setup( );
position( );
}

//~ Methods ----------------------------------------------------------------------------------------------------------------------------

public void setup( )
{
m_switch = new Button( "Switch" );
m_switch.addActionListener( this );
m_show = new Label( "Thing1" );
m_type = 0;
}

public void position( )
{
removeAll( );
setLayout( new GridBagLayout( ) );

GridBagConstraints c = new GridBagConstraints( );

c.gridx = 0;
c.gridy = 0;
c.anchor = GridBagConstraints.WEST;
c.insets = new Insets( 10, 30, 0, 0 );
add( m_switch, c );

c.gridx = 1;
add( m_show, c );
}

public void actionPerformed( ActionEvent e )
{
if ( e.getSource( ) == m_switch )
{
m_show.setText( ( m_type ^= 1 ) == 0 ? "Thing1" : "Thing2" );
}
}

public static void main( String[] args )
{
Frame f = new Frame( );
f.setSize( 200, 200 );
f.add( new JF1( ) );
f.setVisible( true );
}
}

LVL 7

JugglerWCommented: 2004-08-08

> show = java.awt.Label[label2,0,0,0x0,invalid,align=left,text=Thing1] text = Thing2

Seems your label has not size => not layouted correctly.

Compare your code with mine above must be a difference ????

CU

LVL 3

Unimatrix_001Author Commented: 2004-08-08

Got it sorted...it was the GridBagLayout, changed it to GridLayout and it's working!!! :S :S :S

LVL 7

JugglerWCommented: 2004-08-08

Hmmmm? I do not see any reason for this.
Whats your JDK version (java -version), platform (Windows, Linux, ...)?
My code works as listed above with the GridBagLayout. GridLayout is not so nice because it allows only a foxed grid of rows and columns.

Thanks for the points :-)

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