Java Swing: Enabling/Disabling all components in JPanel

Question

I have a JPanel which contains a JToolbar (including few buttons without text) and a JTable and I need to enable/disable (make internal widgets not clickable). I tried this:

 JPanel panel = ....;
 for (Component c : panel.getComponents()) c.setEnabled(enabled);

but it doesn't work. Is there a better and more generic solution to enable/disable all internal components in a JPanel?

I have partially solved my problem using JLayer starting from the example here http://docs.oracle.com/javase/tutorial/uiswing/misc/jlayer.html :

layer = new JLayer<JComponent>(myPanel, new BlurLayerUI(false));
.....
((BlurLayerUI)layer.getUI()).blur(...); // switch blur on/off


class BlurLayerUI extends LayerUI<JComponent> {
  private BufferedImage mOffscreenImage;
  private BufferedImageOp mOperation;

  private boolean blur;

  public BlurLayerUI(boolean blur) {
      this.blur = blur;
      float ninth = 1.0f / 9.0f;
        float[] blurKernel = {
          ninth, ninth, ninth,
          ninth, ninth, ninth,
          ninth, ninth, ninth
        };
        mOperation = new ConvolveOp(
                new Kernel(3, 3, blurKernel),
                ConvolveOp.EDGE_NO_OP, null);
        }

  public void blur(boolean blur) {
      this.blur=blur;
    firePropertyChange("blur", 0, 1);
   }

  @Override
  public void paint (Graphics g, JComponent c) {
      if (!blur) {
            super.paint (g, c);
            return;
        }

      int w = c.getWidth();
    int h = c.getHeight();



    if (w == 0 || h == 0) {
      return;
    }

    // Only create the offscreen image if the one we have
    // is the wrong size.
    if (mOffscreenImage == null ||
            mOffscreenImage.getWidth() != w ||
            mOffscreenImage.getHeight() != h) {
      mOffscreenImage = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
    }

    Graphics2D ig2 = mOffscreenImage.createGraphics();
    ig2.setClip(g.getClip());
    super.paint(ig2, c);
    ig2.dispose();

    Graphics2D g2 = (Graphics2D)g;
    g2.drawImage(mOffscreenImage, mOperation, 0, 0);
  }

  @Override
  public void applyPropertyChange(PropertyChangeEvent pce, JLayer l) {
    if ("blur".equals(pce.getPropertyName())) {
      l.repaint();
    }
  }

}

I still have 2 problems:

1. In the link above events are relative to mouse only. How can I manage the keyboard events?

2. How can I create a "gray out" effect in place of blur?

Answer 1

It requires a recursive call.

import java.awt.*;
import javax.swing.*;

public class DisableAllInContainer {

    public void enableComponents(Container container, boolean enable) {
        Component[] components = container.getComponents();
        for (Component component : components) {
            component.setEnabled(enable);
            if (component instanceof Container) {
                enableComponents((Container)component, enable);
            }
        }
    }

    DisableAllInContainer() {
        JPanel gui = new JPanel(new BorderLayout());

        final JPanel container = new JPanel(new BorderLayout());
        gui.add(container, BorderLayout.CENTER);

        JToolBar tb = new JToolBar();
        container.add(tb, BorderLayout.NORTH);
        for (int ii=0; ii<3; ii++) {
            tb.add(new JButton("Button"));
        }

        JTree tree = new JTree();
        tree.setVisibleRowCount(6);
        container.add(new JScrollPane(tree), BorderLayout.WEST);

        container.add(new JTextArea(5,20), BorderLayout.CENTER);

        final JCheckBox enable = new JCheckBox("Enable", true);
        enable.addActionListener(new ActionListener(){
            @Override
            public void actionPerformed(ActionEvent ae) {
                enableComponents(container, enable.isSelected());
            }
        });
        gui.add(enable, BorderLayout.SOUTH);

        JOptionPane.showMessageDialog(null, gui);
    }

    public static void main(String[] args)  {
        SwingUtilities.invokeLater(new Runnable(){
            @Override
            public void run() {
                new DisableAllInContainer();
            }
        });
    }}

Answer 2

I used the following function:

void setPanelEnabled(JPanel panel, Boolean isEnabled) {
    panel.setEnabled(isEnabled);

    Component[] components = panel.getComponents();

    for(int i = 0; i < components.length; i++) {
        if(components[i].getClass().getName() == "javax.swing.JPanel") {
            setPanelEnabled((JPanel) components[i], isEnabled);
        }

        components[i].setEnabled(isEnabled);
    }
}

Answer 3

you can overlay whole Container / JComponent

1. GlassPane block by default MouseEvents, but not Keyboard, required consume all keyevents from ToolKit

2. JLayer (Java7) based on JXLayer (Java6)

3. can't see reason(s) why not works for you

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JCheckBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.border.LineBorder;

public class AddComponentsAtRuntime {

    private JFrame f;
    private JPanel panel;
    private JCheckBox checkValidate, checkReValidate, checkRepaint, checkPack;

    public AddComponentsAtRuntime() {
        JButton b = new JButton();
        //b.setBackground(Color.red);
        b.setBorder(new LineBorder(Color.black, 2));
        b.setPreferredSize(new Dimension(600, 20));
        panel = new JPanel(new GridLayout(0, 1));
        panel.add(b);
        f = new JFrame();
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(panel, "Center");
        f.add(getCheckBoxPanel(), "South");
        f.setLocation(200, 200);
        f.pack();
        f.setVisible(true);
    }

    private JPanel getCheckBoxPanel() {
        checkValidate = new JCheckBox("validate");
        checkValidate.setSelected(false);
        checkReValidate = new JCheckBox("revalidate");
        checkReValidate.setSelected(true);
        checkRepaint = new JCheckBox("repaint");
        checkRepaint.setSelected(true);
        checkPack = new JCheckBox("pack");
        checkPack.setSelected(true);
        JButton addComp = new JButton("Add New One");
        addComp.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                JButton b = new JButton();
                //b.setBackground(Color.red);
                b.setBorder(new LineBorder(Color.black, 2));
                b.setPreferredSize(new Dimension(400, 10));
                panel.add(b);
                makeChange();
                System.out.println(" Components Count after Adds :" + panel.getComponentCount());
            }
        });
        JButton removeComp = new JButton("Remove One");
        removeComp.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                int count = panel.getComponentCount();
                if (count > 0) {
                    panel.remove(0);
                }
                makeChange();
                System.out.println(" Components Count after Removes :" + panel.getComponentCount());
            }
        });
        JButton disabledComp = new JButton("Disabled All");
        disabledComp.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                for (Component c : panel.getComponents()) {
                    c.setEnabled(false);
                }
            }
        });
        JButton enabledComp = new JButton("Enabled All");
        enabledComp.addActionListener(new ActionListener() {

            @Override
            public void actionPerformed(ActionEvent e) {
                for (Component c : panel.getComponents()) {
                    c.setEnabled(true);
                }
            }
        });
        JPanel panel2 = new JPanel();
        panel2.add(checkValidate);
        panel2.add(checkReValidate);
        panel2.add(checkRepaint);
        panel2.add(checkPack);
        panel2.add(addComp);
        panel2.add(removeComp);
        panel2.add(disabledComp);
        panel2.add(enabledComp);
        return panel2;
    }

    private void makeChange() {
        if (checkValidate.isSelected()) {
            panel.validate();
        }
        if (checkReValidate.isSelected()) {
            panel.revalidate();
        }
        if (checkRepaint.isSelected()) {
            panel.repaint();
        }
        if (checkPack.isSelected()) {
            f.pack();
        }
    }

    public static void main(String[] args) {
        AddComponentsAtRuntime makingChanges = new AddComponentsAtRuntime();
    }
}

Answer 4

@Kesavamoorthi if you want to make it more general:

void setPanelEnabled(java.awt.Container cont, Boolean isEnabled) {
    cont.setEnabled(isEnabled);

    java.awt.Component[] components = cont.getComponents();

    for (int i = 0; i < components.length; i++) {
        if (components[i] instanceof java.awt.Container) {
            setPanelEnabled((java.awt.Container) components[i], isEnabled);
        }
        components[i].setEnabled(isEnabled);
    }
}