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I have a series of components underneath each other in a JPanel set as a GridLayout.
I need to temporarily hide the components but setVisible(false) doesn't cut it, because there is still an empty gap where the components were.
Is there a quick and easy way to do this? Or do I have to stay saving the state of the JPanel, removing the components, then restoring it?
SSCCE:
[GridLayout2.java]
import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.Insets;
public class GridLayout2 extends GridLayout
{
public GridLayout2() {
this(1, 0, 0, 0);
}
public GridLayout2(int rows, int cols) {
this(rows, cols, 0, 0);
}
public GridLayout2(int rows, int cols, int hgap, int vgap) {
super(rows, cols, hgap, vgap);
}
public Dimension preferredLayoutSize(Container parent) {
//System.err.println("preferredLayoutSize");
synchronized (parent.getTreeLock()) {
Insets insets = parent.getInsets();
int ncomponents = parent.getComponentCount();
int nrows = getRows();
int ncols = getColumns();
if (nrows > 0) {
ncols = (ncomponents + nrows - 1) / nrows;
}
else {
nrows = (ncomponents + ncols - 1) / ncols;
}
int[] w = new int[ncols];
int[] h = new int[nrows];
for (int i = 0; i < ncomponents; i ++) {
int r = i / ncols;
int c = i % ncols;
Component comp = parent.getComponent(i);
Dimension d = comp.getPreferredSize();
if (w[c] < d.width) {
w[c] = d.width;
}
if (h[r] < d.height) {
h[r] = d.height;
}
}
int nw = 0;
for (int j = 0; j < ncols; j ++) {
nw += w[j];
}
int nh = 0;
for (int i = 0; i < nrows; i ++) {
nh += h[i];
}
return new Dimension(insets.left + insets.right + nw + (ncols-1)*getHgap(),
insets.top + insets.bottom + nh + (nrows-1)*getVgap());
}
}
public Dimension minimumLayoutSize(Container parent) {
System.err.println("minimumLayoutSize");
synchronized (parent.getTreeLock()) {
Insets insets = parent.getInsets();
int ncomponents = parent.getComponentCount();
int nrows = getRows();
int ncols = getColumns();
if (nrows > 0) {
ncols = (ncomponents + nrows - 1) / nrows;
}
else {
nrows = (ncomponents + ncols - 1) / ncols;
}
int[] w = new int[ncols];
int[] h = new int[nrows];
for (int i = 0; i < ncomponents; i ++) {
int r = i / ncols;
int c = i % ncols;
Component comp = parent.getComponent(i);
Dimension d = comp.getMinimumSize();
if (w[c] < d.width) {
w[c] = d.width;
}
if (h[r] < d.height) {
h[r] = d.height;
}
}
int nw = 0;
for (int j = 0; j < ncols; j ++) {
nw += w[j];
}
int nh = 0;
for (int i = 0; i < nrows; i ++) {
nh += h[i];
}
return new Dimension(insets.left + insets.right + nw + (ncols-1)*getHgap(),
insets.top + insets.bottom + nh + (nrows-1)*getVgap());
}
}
public void layoutContainer(Container parent) {
//System.err.println("layoutContainer");
synchronized (parent.getTreeLock()) {
Insets insets = parent.getInsets();
int ncomponents = parent.getComponentCount();
int nrows = getRows();
int ncols = getColumns();
if (ncomponents == 0) {
return;
}
if (nrows > 0) {
ncols = (ncomponents + nrows - 1) / nrows;
}
else {
nrows = (ncomponents + ncols - 1) / ncols;
}
int hgap = getHgap();
int vgap = getVgap();
// scaling factors
Dimension pd = preferredLayoutSize(parent);
double sw = (1.0 * parent.getWidth()) / pd.width;
double sh = (1.0 * parent.getHeight()) / pd.height;
// scale
int[] w = new int[ncols];
int[] h = new int[nrows];
for (int i = 0; i < ncomponents; i ++) {
int r = i / ncols;
int c = i % ncols;
Component comp = parent.getComponent(i);
Dimension d = comp.getPreferredSize();
d.width = (int) (sw * d.width);
d.height = (int) (sh * d.height);
if (w[c] < d.width) {
w[c] = d.width;
}
if (h[r] < d.height) {
h[r] = d.height;
}
}
for (int c = 0, x = insets.left; c < ncols; c ++) {
for (int r = 0, y = insets.top; r < nrows; r ++) {
int i = r * ncols + c;
if (i < ncomponents) {
parent.getComponent(i).setBounds(x, y, w[c], h[r]);
}
y += h[r] + vgap;
}
x += w[c] + hgap;
}
}
}
}
[SSCCE.java]
import java.awt.Color;
import javax.swing.*;
import javax.swing.border.*;
public class SSCCE extends JFrame{
JPanel innerPane = new JPanel();
JScrollPane scr = new JScrollPane(innerPane);
public static void main(String[] args) {
new SSCCE();
}
public SSCCE() {
setSize(400, 800);
innerPane.setLayout(new GridLayout2(0, 1));
add(scr);
for (int i = 0; i < 30; i++)
{
innerPane.add(getPane());
}
setVisible(true);
try {
Thread.sleep(2000);
} catch (InterruptedException e) {}
for (int i = 0; i < 30; i++)
{
if (i%2==0)
innerPane.getComponent(i).setVisible(false);
}
}
private JPanel getPane()
{
JPanel ret = new JPanel();
JLabel lbl = new JLabel("This is a pane.");
ret.add(lbl);
ret.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
ret.setBackground(Color.gray);
return ret;
}
}
945
Following this answer you can put super(new FlowLayout ( FlowLayout. CENTER, 0, 0 )); at the top of your JPanel class. This will remove the padding between buttons within the class you are programming.
You can simply create your jPanel using drag and drop, as you always do and then for changing the panel's color and making it transparent or semi-transparent you can use this code: panel. setBackground(new Color(0.0f, 0.0f, 0.0f, 0.5f));
You can put many operations inside one panel. JPanel is a subclass of JComponent, and JComponent is a subclass of Container, therefore, JPanel is also a container. There are so many methods that can be used for JPanel, which it inherited from its super classes.
The setVisible(true) method makes the frame appear on the screen. If you forget to do this, the frame object will exist as an object in memory, but no picture will appear on the screen.
because there is still an empty gap where the components were.
Yes, GridLayout is not that smart. It just uses the total number of components to determine the number of row/columns.
Is there a quick and easy way to do this?
I would create a custom layout manager. Just copy the GridLayout code and make a couple of changes. The basic changes would be:
Override the ncomponents variable. Instead of just using the number of components on the panel you would need to loop thorugh all the components and count the visible ones.
In the layout code you would need to add an if (visible) check.
Edit:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
public class InvisibleGridLayout implements LayoutManager, java.io.Serializable
{
int hgap;
int vgap;
int rows;
int cols;
public InvisibleGridLayout() {
this(1, 0, 0, 0);
}
public InvisibleGridLayout(int rows, int cols) {
this(rows, cols, 0, 0);
}
public InvisibleGridLayout(int rows, int cols, int hgap, int vgap) {
if ((rows == 0) && (cols == 0)) {
throw new IllegalArgumentException("rows and cols cannot both be zero");
}
this.rows = rows;
this.cols = cols;
this.hgap = hgap;
this.vgap = vgap;
}
public int getRows() {
return rows;
}
public void setRows(int rows) {
if ((rows == 0) && (this.cols == 0)) {
throw new IllegalArgumentException("rows and cols cannot both be zero");
}
this.rows = rows;
}
public int getColumns() {
return cols;
}
public void setColumns(int cols) {
if ((cols == 0) && (this.rows == 0)) {
throw new IllegalArgumentException("rows and cols cannot both be zero");
}
this.cols = cols;
}
public int getHgap() {
return hgap;
}
public void setHgap(int hgap) {
this.hgap = hgap;
}
public int getVgap() {
return vgap;
}
public void setVgap(int vgap) {
this.vgap = vgap;
}
public void addLayoutComponent(String name, Component comp) {
}
public void removeLayoutComponent(Component comp) {
}
public Dimension preferredLayoutSize(Container parent) {
synchronized (parent.getTreeLock()) {
Insets insets = parent.getInsets();
// int ncomponents = parent.getComponentCount();
int ncomponents = getVisibleComponents(parent);
int nrows = rows;
int ncols = cols;
if (nrows > 0) {
ncols = (ncomponents + nrows - 1) / nrows;
} else {
nrows = (ncomponents + ncols - 1) / ncols;
}
int w = 0;
int h = 0;
// for (int i = 0 ; i < ncomponents ; i++) {
for (int i = 0 ; i < parent.getComponentCount(); i++) {
Component comp = parent.getComponent(i);
if (!comp.isVisible()) continue; // added
Dimension d = comp.getPreferredSize();
if (w < d.width) {
w = d.width;
}
if (h < d.height) {
h = d.height;
}
}
Dimension d = new Dimension(insets.left + insets.right + ncols*w + (ncols-1)*hgap,
insets.top + insets.bottom + nrows*h + (nrows-1)*vgap);
return d;
}
}
public Dimension minimumLayoutSize(Container parent) {
synchronized (parent.getTreeLock()) {
Insets insets = parent.getInsets();
// int ncomponents = parent.getComponentCount();
int ncomponents = getVisibleComponents(parent);
int nrows = rows;
int ncols = cols;
if (nrows > 0) {
ncols = (ncomponents + nrows - 1) / nrows;
} else {
nrows = (ncomponents + ncols - 1) / ncols;
}
int w = 0;
int h = 0;
// for (int i = 0 ; i < ncomponents ; i++) {
for (int i = 0 ; i < parent.getComponentCount(); i++) {
Component comp = parent.getComponent(i);
if (!comp.isVisible()) continue; // added
Dimension d = comp.getMinimumSize();
if (w < d.width) {
w = d.width;
}
if (h < d.height) {
h = d.height;
}
}
Dimension d = new Dimension(insets.left + insets.right + ncols*w + (ncols-1)*hgap,
insets.top + insets.bottom + nrows*h + (nrows-1)*vgap);
return d;
}
}
public void layoutContainer(Container parent) {
synchronized (parent.getTreeLock()) {
Insets insets = parent.getInsets();
// int ncomponents = parent.getComponentCount();
int ncomponents = getVisibleComponents(parent);
int nrows = rows;
int ncols = cols;
boolean ltr = parent.getComponentOrientation().isLeftToRight();
if (ncomponents == 0) {
return;
}
if (nrows > 0) {
ncols = (ncomponents + nrows - 1) / nrows;
} else {
nrows = (ncomponents + ncols - 1) / ncols;
}
// int w = parent.width - (insets.left + insets.right);
// int h = parent.height - (insets.top + insets.bottom);
int w = parent.getSize().width - (insets.left + insets.right);
int h = parent.getSize().height - (insets.top + insets.bottom);
w = (w - (ncols - 1) * hgap) / ncols;
h = (h - (nrows - 1) * vgap) / nrows;
/*
if (ltr) {
for (int c = 0, x = insets.left ; c < ncols ; c++, x += w + hgap) {
for (int r = 0, y = insets.top ; r < nrows ; r++, y += h + vgap) {
int i = r * ncols + c;
if (i < ncomponents) {
parent.getComponent(i).setBounds(x, y, w, h);
}
}
}
} else {
// for (int c = 0, x = parent.width - insets.right - w; c < ncols ; c++, x -= w + hgap) {
for (int c = 0, x = parent.getSize().width - insets.right - w; c < ncols ; c++, x -= w + hgap) {
for (int r = 0, y = insets.top ; r < nrows ; r++, y += h + vgap) {
int i = r * ncols + c;
if (i < ncomponents) {
parent.getComponent(i).setBounds(x, y, w, h);
}
}
}
}
}
*/
int i = 0;
if (ltr)
{
for (int r = 0, y = insets.top ; r < nrows ; r++, y += h + vgap)
{
int c = 0;
int x = insets.left;
while (c < ncols)
{
if (i >= parent.getComponentCount()) break;
Component component = parent.getComponent(i);
if (component.isVisible())
{
parent.getComponent(i).setBounds(x, y, w, h);
c++;
x += w + hgap;
}
i++;
}
}
}
}}
private int getVisibleComponents(Container parent)
{
int visible = 0;
for (Component c: parent.getComponents())
{
if (c.isVisible())
visible++;
}
return visible;
}
public String toString() {
return getClass().getName() + "[hgap=" + hgap + ",vgap=" + vgap +
",rows=" + rows + ",cols=" + cols + "]";
}
public static void main(String[] args)
{
final JPanel innerPane = new JPanel();
JScrollPane scr = new JScrollPane(innerPane);
innerPane.setLayout(new InvisibleGridLayout(0, 3));
for (int i = 0; i < 30; i++)
{
JPanel ret = new JPanel();
JLabel lbl = new JLabel("This is pane " + i);
ret.add(lbl);
ret.setBorder(BorderFactory.createBevelBorder(BevelBorder.RAISED));
ret.setBackground(Color.gray);
innerPane.add(ret);
}
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(scr);
frame.setBounds(400, 0, 400, 700);
frame.setVisible(true);
javax.swing.Timer timer = new javax.swing.Timer(2000, new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
for (int i = 0; i < 30; i++)
{
if (i%2==0)
innerPane.getComponent(i).setVisible(false);
}
}
});
timer.setRepeats(false);
timer.start();
}
}
Here are 3 ways off the top of my head.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class HideComponents {
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JPanel gui = new JPanel(new BorderLayout());
JToolBar tb = new JToolBar();
gui.add(tb, BorderLayout.NORTH);
final JButton openTool = new JButton("Open");
final JButton saveTool = new JButton("Save");
tb.add( openTool );
tb.add( saveTool );
JPanel buttonFlow = new JPanel(new FlowLayout(3));
gui.add(buttonFlow, BorderLayout.CENTER);
final JButton openFlow = new JButton("Open");
final JButton saveFlow = new JButton("Save");
buttonFlow.add( openFlow );
buttonFlow.add( saveFlow );
JPanel buttonBox = new JPanel();
gui.add(buttonBox, BorderLayout.EAST);
BoxLayout bl = new BoxLayout(buttonBox, BoxLayout.Y_AXIS);
buttonBox.setLayout(bl);
final JButton openBox = new JButton("Open");
final JButton saveBox = new JButton("Save");
buttonBox.add( openBox );
buttonBox.add( saveBox );
final JCheckBox openChoice = new JCheckBox("Show open", true);
openChoice.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
openTool.setVisible(openChoice.isSelected());
openFlow.setVisible(openChoice.isSelected());
openBox.setVisible(openChoice.isSelected());
}
});
gui.add(openChoice, BorderLayout.SOUTH);
JOptionPane.showMessageDialog(null, gui);
}
});
}
}
Please consider swapping:
button.setVisible(false);
For:
button.setEnabled(false);
This will be more intuitive to most users who view the GUI, and has the same ultimate effect.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
class DisableComponents {
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
JPanel gui = new JPanel(new BorderLayout());
JToolBar tb = new JToolBar();
gui.add(tb, BorderLayout.NORTH);
final JButton openTool = new JButton("Open");
final JButton saveTool = new JButton("Save");
tb.add( openTool );
tb.add( saveTool );
JPanel buttonFlow = new JPanel(new FlowLayout(3));
gui.add(buttonFlow, BorderLayout.CENTER);
final JButton openFlow = new JButton("Open");
final JButton saveFlow = new JButton("Save");
buttonFlow.add( openFlow );
buttonFlow.add( saveFlow );
JPanel buttonBox = new JPanel();
gui.add(buttonBox, BorderLayout.EAST);
BoxLayout bl = new BoxLayout(buttonBox, BoxLayout.Y_AXIS);
buttonBox.setLayout(bl);
final JButton openBox = new JButton("Open");
final JButton saveBox = new JButton("Save");
buttonBox.add( openBox );
buttonBox.add( saveBox );
final JCheckBox openChoice = new JCheckBox("Enable open", true);
openChoice.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
openTool.setEnabled(openChoice.isSelected());
openFlow.setEnabled(openChoice.isSelected());
openBox.setEnabled(openChoice.isSelected());
}
});
gui.add(openChoice, BorderLayout.SOUTH);
JOptionPane.showMessageDialog(null, gui);
}
});
}
}
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