Re: setLookAndFeel problem

From:
Lew <noone@lewscanon.com>
Newsgroups:
comp.lang.java.gui
Date:
Sun, 14 Feb 2010 13:20:29 -0500
Message-ID:
<hl9ete$sbh$1@news.albasani.net>
Amr wrote:

im [sic] testing a simple code for an ActionLIstener event for a button.
the expected outcome with the functionality of the button is ok.
but i [sic] couldn't set the *theme* get displayed.
i.e. the method calling lookAndFeel() does not seems to work.


How did you decide that it didn't work? To rephrase, precisely what steps did
you use to verify your conclusion?

According to the Javadocs
<http://java.sun.com/javase/6/docs/api/javax/swing/UIManager.html>

The class used for the default look and feel is chosen
in the following manner:

1. If the system property swing.defaultlaf is non-null,
   use its value as the default look and feel class name.
2. If the Properties file swing.properties exists and
   contains the key swing.defaultlaf, use its value as the
   default look and feel class name. ...
3. Otherwise use the cross platform [sic] look and feel.


Are you certain that 1 and 2 do not apply?

Perhaps if you confine GUI actions to the Event Dispatch Thread (EDT) your
problem will go away.

import java.awt.*;
import java.awt.event.*;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;

public class AL extends Frame implements WindowListener,ActionListener
{
    TextField text = new TextField(20);

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     Button b;
    private int numClicks = 0;

    public static void main(String[] args) {

        AL myWindow = new AL("My first window");
        myWindow.setSize(350,100);
        myWindow.setVisible(true);

All GUI action must occur on the EDT. You can get weird bugs otherwise.

     }

    public AL(String title) {

        super(title);
        setLayout(new FlowLayout());
        addWindowListener(this);
        lookAndFeel();

        b = new Button("Click me");
        add(b);
        add(text);
        b.addActionListener(this);
    }

    public void lookAndFeel(){
        try{
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        SwingUtilities.updateComponentTreeUI(this);
        }catch(Exception e){
            System.out.println("errr");
        }
    }

    public void actionPerformed(ActionEvent e) {
        numClicks++;
        text.setText("Button Clicked " + numClicks + " times");
    }

    public void windowClosing(WindowEvent e) {
        dispose();
        System.exit(0);
    }

    public void windowOpened(WindowEvent e) {}
    public void windowActivated(WindowEvent e) {}
    public void windowIconified(WindowEvent e) {}
    public void windowDeiconified(WindowEvent e) {}
    public void windowDeactivated(WindowEvent e) {}
    public void windowClosed(WindowEvent e) {}
}


Provide an SSCCE with the GUI actions refactored to happen only on the EDT.

--
Lew

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