[Java] create opague 'JPanel' above other elements?

[SpinningAround]

I have a JFrame that uses BorderLayout (West,Center,North is used), what I would like to create is a overlay that cover the entire JFrame. So when a certain requirement is meet will the window gray out. Something similar to what is shown in the attachment (gray layer above).

[kahumba]

JFrame has a special component for this, it's called the "Glass pane":
http://java.sun.com/docs/books/tutorial/uiswing/components/rootpane.html

but, it took me quite a while to get it to work the way I wanted, maybe you'll have a better time getting used to it.

[Reiger]

If all you want to do is mark the frame as “disabled” then myJFrameObject.setEnabled(false); ought to work just fine.

[SpinningAround]

Thanks, I got it to some extent working using the glass pane. I realized that I was looking more for transparent/translucent, glass pane manage to do this also but there is one problem. When I use translucent Color(int r, int b, int g, int a) and repaint command does the program add layer upon layer that remove the translucent effect after a few repaints, question is how to make it refresh itself instead of painting a new above the latest?




public void inactive() throws InterruptedException{
//setup glass pane
JPanel glass = (JPanel) mainFrame.getGlassPane();
Color colorA = new Color(200,200,200,200);
glass.setLayout(new GridLayout(0,1));
glass.setOpaque(true);
glass.setBackground(colorA);

//create a JTextArea to write message in
JTextArea inactive = new JTextArea("Program inactive, will restart after countdown.");
inactive.setForeground(Color.red);
inactive.setEditable(false);
inactive.setLineWrap(true);
inactive.setWrapStyleWord(true);
inactive.setOpaque(false);

//JLabel to contain countdown
JLabel inactiveCountdown = new JLabel("Time left:");
inactiveCountdown.setForeground(Color.red);

//finalize frame
glass.add(inactive);
glass.add(inactiveCountdown);
glass.setVisible(true);

//initiate countdown
Calendar DATE = Calendar.getInstance();
int hour = DATE.get(Calendar.HOUR_OF_DAY),thishour=hour;

//start countdown, exit when finished
while(thishour==hour){
DATE = Calendar.getInstance();
inactiveCountdown.setText("Time left: " +
Integer.toString( 59-DATE.get(Calendar.MINUTE) ) + "min " + Integer.toString( 59-DATE.get(Calendar.SECOND) ) + "s" ) );
thishour = DATE.get(Calendar.HOUR_OF_DAY);
mainFrame.repaint();
Thread.currentThread().sleep(1000);
}
glass.setVisible(false);
mainFrame.repaint();
}

[kahumba]

A example of what you're doing that compiles and runs would be great.
The way I implemented my solution didn't require tinkering with the alpha bits, I've overriden glasspane's paintComponent method and used AlphaComposite to draw the contents of the content pane upon the glasspane which creates the illusion of transparency and then draw normally anything that belongs to the glasspane, thus it looks like the glasspane (with a red label up and a textfield a button one line below) is in front with anything else faded away in the background.
I don't know if I make myself clear or if I understood your correctly.



@Override
public void paintComponent(Graphics gr) {
if(gr == null) {
return;
}

if(!inited) {
inited = true;
initComponents();
}

Main.itself().getContentPane().paint(gr);
Graphics2D g = (Graphics2D)gr;
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING , RenderingHints.VALUE_ANTIALIAS_ON);
g.setComposite(AlphaComposite.getInstance(AlphaCom posite.SRC_OVER, 0.6f));
g.setColor(Color.white);
int w = getWidth(), h = getHeight();
g.fillRect(0,0,w,h);

g.setColor(Color.red);
g.setFont(new Font(Font.DIALOG, Font.PLAIN, 18));
g.setComposite(AlphaComposite.getInstance(AlphaCom posite.SRC_OVER, 1f));
String s = "Поиск:";

FontMetrics fm = g.getFontMetrics();
int msg_width = fm.stringWidth(s);
int msg_x = getSize().width / 2 - msg_width / 2;
g.drawString (s, msg_x, startY-ygap);

}

[SpinningAround]

It solved it :) But for some wired reason don't the glass pane cover the entire frame.



import java.awt.*;
import javax.swing.*;
public class Test extends JFrame{
JPanel glass = (JPanel) getGlassPane();
public Test(){
setVisible(true);
setSize(new Dimension(200,300));
JLabel a = new JLabel("a");
add(a);
Container cp = getContentPane();
cp.setBackground(Color.green);

JLabel c = new JLabel("RED");
c.setForeground(Color.red);
glass.add(c);

JTextField d = new JTextField("d",5);
glass.add(d);
}

public void paint(Graphics g){
super.paint(g);
glass.setVisible(true);
Graphics2D g2d = (Graphics2D) g;
AlphaComposite newComposite = AlphaComposite.getInstance(AlphaComposite.SRC_OVER , .7f);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASI NG, RenderingHints.VALUE_ANTIALIAS_ON);
g2d.setComposite(newComposite);
g2d.setColor(Color.white);
g2d.fillRect(0,0,glass.getWidth(),glass.getHeight( ));

newComposite = AlphaComposite.getInstance(AlphaComposite.SRC_OVER , 1f);
g2d.setComposite(newComposite);
g2d.drawString("Sunshine",50,100);

}

public static void main (String args[]) {
Test b = new Test();
b.repaint();
}
}

[kahumba]

If you wanna live a long happy life better put the glass pane code into a new class:

Test.java (the JFrame)


import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class Test extends JFrame implements ActionListener {

public Test() {
setGlassPane(new MyGlass(getContentPane()));

Container cp = getContentPane();
cp.setLayout(new BoxLayout(cp, BoxLayout.PAGE_AXIS));
cp.setBackground(Color.green);

cp.add(new JLabel("Content pane Label"));
cp.add(Box.createVerticalStrut(20));

JLabel label = new JLabel("Content pane Red Label");
label.setForeground(Color.red);
cp.add(label);
cp.add(Box.createVerticalStrut(20));

JButton btn = new JButton("ContentPane button (enables glass pane)");
btn.addActionListener(this);
cp.add(btn);

setDefaultCloseOperation(EXIT_ON_CLOSE);
setSize(new Dimension(400, 300));
setVisible(true);
}

public static void main(String args[]) {
new Test();
}

public void actionPerformed(ActionEvent ae) {
getGlassPane().setVisible(true);
}
}
MyGlass.java (The glass pane)



import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;

public class MyGlass extends JPanel implements ActionListener {
private Container contentPane;
private boolean inited;
JPasswordField pass;

public MyGlass(Container contentPane) {
this.contentPane = contentPane;
setLayout(null);

}

private void init() {
inited = true;
//let's have some fun, ask for a password
JLabel label = new JLabel("(glass pane JLabel) Enter password and hit enter:");
label.setForeground(Color.blue);
add(label);
label.setBounds(40, getHeight()/2, 350, 20);

pass = new JPasswordField("password");
add(pass);
pass.addActionListener(this);
pass.setBounds(40, getHeight()/2+20, 250, 20);
pass.requestFocus();
}

@Override
public void paintComponent(Graphics gr) {
super.paintComponent(gr);//makes sure MyGlass's widgets are drawn automatically

if(!inited) {
init();
}

Graphics2D g = (Graphics2D) gr;
//create (fake) transparency
AlphaComposite transparent = AlphaComposite.getInstance(AlphaComposite.SRC_OVER , .7f);
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING , RenderingHints.VALUE_ANTIALIAS_ON);
g.setComposite(transparent);
//draw the contents of the JFrame's content pane upon our glass pane.
contentPane.paint(gr);
g.setColor(Color.white);
g.fillRect(0, 0, getWidth(), getHeight());

AlphaComposite solid = AlphaComposite.getInstance(AlphaComposite.SRC_OVER , 1f);
g.setComposite(solid);
g.setColor(Color.black);
g.drawString("Glass pane string", 50, 100);
g.drawString("which is drawn manually!", 50, 120);
}

public void actionPerformed(ActionEvent ae) {
setVisible(false);
}
}

[SpinningAround]

wow, thanks :D