Glasspane repainting problem

Question

Hi All,
I am facing a strange problem with a semi-transparent glass pane. The code is pasted below. Every time the window repaints(by switching between applications), the window becomes darker and darker. and is completely dark after some time. Any solution ?
Here is the code.
package glass;
import java.awt.Color;
import java.awt.GridBagLayout;
import java.awt.event.KeyAdapter;
import java.awt.event.MouseAdapter;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Class1 extends JFrame{
    public Class1() {
        super();
        initUI();
        pack();
        this.setSize(100,100);
        setDefaultCloseOperation(EXIT_ON_CLOSE);
    private void initUI() {
    public static void main(String[] args) {
            Class1 cs = new Class1();
        JTest tst = cs.new JTest();
        cs.setGlassPane(tst);
        tst.setVisible(true);
            cs.setVisible(true);
    private class JTest extends JPanel {
    public JTest() {
        setLayout(new GridBagLayout());
        //setOpaque(false);
        setBackground(new Color(10, 10, 10, 20));
        // Block events
        addMouseListener(new MouseAdapter() {});
        addKeyListener(new KeyAdapter() {});
   

Answer 1

camickr wrote:
There are two key points:
a) the component is opaque, which means the parents background must be painted.
b) because the component is opaque, we needed to override the paintComponent() method to force the painting of the background using the transparent color
The concept should work for a JPanel as well as a JComponent.Thank you so much!
I just wanted to note that this worked for me with some slight modification:
a) Use setOpaque(false)
b) Since the component is no longer opaque, it's background color will not be displayed, so overriding the paintComponent method does indeed force painting of the background. But you can't just setBackground(some_color), you actually need to use fillRect to fill the components area with that transluscent color, since the background color won't be displayed if the component isn't set to be opaque.
-Kyle