Related
i have a problem with refreshing the values of my gridlayout.
So, i have a JPanel in a JFrame and in that JPanel , once i entered two values(one for rows and one for columns) and then by clicking on validate, i get a GridLayout with the previous values of JButtons.
So for exemple if I enter (2,2) i get a GridLayout of 4 JButtons and in each JButton i have an image.
So my problem here is, every time i wanna refresh the GridLayout by changing the values, it doesn’t work, the GridLayout doesn’t change, or if it change, the JButtons are inclickable.
I feel like every time i click on Validate, a new GridLayout is created on my JPanel, but the first one is still there.
I will upload two pictures, one with the normal functioning (entering values first time), and the second with the bug (entering new values).
Thanks guys.
First values
Second values
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Color;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.awt.event.ActionEvent;
import javax.swing.*;
public class PagePrincipal extends JFrame implements ActionListener {
JButton Valider;
JTextField Columns;
JTextField Rows;
ArrayList<JButton> butt;
public PagePrincipal(){
getContentPane().setLayout(null); //this is not the panel that contains the GridLayout
Columns = new JTextField();
Columns.setBounds(219, 35, 197, 57);
getContentPane().add(Columns);
Columns.setColumns(10);
Rows = new JTextField();
Rows.setBounds(451, 35, 226, 57);
getContentPane().add(Rows);
Rows.setColumns(10);
Valider = new JButton();
Valider.setBackground(new Color(65, 179, 163));
Valider.setForeground(Color.WHITE);
Valider.setFont(new Font("Bookman Old Style", Font.BOLD, 20));
Valider.setBounds(704, 15, 268, 81);
Valider.setText("Validation");
Valider.addActionListener(this);
this.add(Valider);
this.setResizable(true);
this.setVisible(true);
this.setExtendedState(JFrame.MAXIMIZED_BOTH);
}
#Override
public void actionPerformed(ActionEvent event) {
if (event.getSource() == Valider) {
int NbRows= Integer.parseInt(Rows.getText());
int NbColumns=Integer.parseInt(Columns.getText());
JButton button[] = new JButton[NbRows*NbColumns];
butt = new ArrayList<>();
setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel botPanel = new JPanel(); //this is the panel that contains the GridLayout
botPanel.setBounds(100, 200, 1000, 400);
this.add(botPanel);
botPanel.setLayout(new GridLayout(NbRows,NbColumns));
for (int i=0; i<NbRows*NbColumns; i++){
button[i]=new JButton();
botPanel.add(button[i]);
butt.add(button[i]);
}
this.setVisible(true);
}
}
}
Again, avoid null layouts if at all possible, since they force you to create rigid, inflexible, hard to maintain GUI's that might work on one platform only. Instead, nest JPanels, each using its own layout to help create GUI's that look good, are flexible, extendable and that work.
Also, when changing components held within a container, call revalidate() and repaint() on the container after making the changes. For example, the following GUI:
Is created with the following code:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
public class PagePrincipal2 extends JPanel {
public static final int MAX_ROWS = 40;
public static final int MAX_COLS = 12;
private JButton validatorButton = new JButton("Validate");
private JSpinner columnsSpinner = new JSpinner(new SpinnerNumberModel(2, 1, MAX_COLS, 1));
private JSpinner rowsSpinner = new JSpinner(new SpinnerNumberModel(2, 1, MAX_ROWS, 1));
private List<JButton> buttonsList = new ArrayList<>();
private JPanel gridPanel = new JPanel();
public PagePrincipal2() {
JPanel topPanel = new JPanel();
topPanel.add(new JLabel("Columns:"));
topPanel.add(columnsSpinner);
topPanel.add(Box.createHorizontalStrut(10));
topPanel.add(new JLabel("Rows:"));
topPanel.add(rowsSpinner);
topPanel.add(Box.createHorizontalStrut(10));
topPanel.add(validatorButton);
JScrollPane scrollPane = new JScrollPane(gridPanel);
int gridWidth = 1000;
int gridHeight = 600;
scrollPane.setPreferredSize(new Dimension(gridWidth, gridHeight));
setLayout(new BorderLayout());
add(topPanel, BorderLayout.PAGE_START);
add(scrollPane, BorderLayout.CENTER);
validatorButton.addActionListener(e -> validateGrid());
}
private void validateGrid() {
int nbRows = (int) rowsSpinner.getValue();
int nbColumns = (int) columnsSpinner.getValue();
gridPanel.removeAll();
buttonsList.clear();
gridPanel.setLayout(new GridLayout(nbRows, nbColumns));
for (int i = 0; i < nbRows * nbColumns; i++) {
int column = i % nbColumns;
int row = i / nbColumns;
String text = String.format("[%02d, %02d]", column, row);
JButton button = new JButton(text);
button.addActionListener(e -> gridButtonAction(column, row));
buttonsList.add(button);
gridPanel.add(button);
}
gridPanel.revalidate();
gridPanel.repaint();
}
private void gridButtonAction(int column, int row) {
String message = String.format("Button pressed: [%02d, %02d]", column, row);
String title = "Grid Button Press";
int type = JOptionPane.INFORMATION_MESSAGE;
JOptionPane.showMessageDialog(this, message, title, type);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
PagePrincipal2 mainPanel = new PagePrincipal2();
JFrame frame = new JFrame("GUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
});
}
}
Note that the gridPanel, the one holding the buttons, is placed into a JScrollPane:
JScrollPane scrollPane = new JScrollPane(gridPanel);
Note that the main JPanel that holds everything is given a BorderLayout, and then 2 components are added, a topPanel JPanel that holds labels, buttons and fields for data input, added at the BorderLayout.PAGE_START, the top position, and the JScrollPane is added to the main JPanel at the BorderLayout.CENTER position:
setLayout(new BorderLayout());
add(topPanel, BorderLayout.PAGE_START);
add(scrollPane, BorderLayout.CENTER);
When the old buttons are removed from the gridPanel, and then new buttons are added, I will call revalidate() and repaint() on the gridPanel, the first method to get the layout managers to layout the new components, and the second method call to remove any dirty pixels that may be present:
private void validateGrid() {
int nbRows = (int) rowsSpinner.getValue();
int nbColumns = (int) columnsSpinner.getValue();
gridPanel.removeAll();
buttonsList.clear();
gridPanel.setLayout(new GridLayout(nbRows, nbColumns));
for (int i = 0; i < nbRows * nbColumns; i++) {
int column = i % nbColumns;
int row = i / nbColumns;
String text = String.format("[%02d, %02d]", column, row);
JButton button = new JButton(text);
button.addActionListener(e -> gridButtonAction(column, row));
buttonsList.add(button);
gridPanel.add(button);
}
gridPanel.revalidate();
gridPanel.repaint();
}
i want a scrollpane on my GUI. The area, i want to have "scrollable" is a JPanel without any LayoutManager, because the content is something between static and dynamic... but maybe a part of my code will help
Here it is:
pane = getContentPane();
jpane = new JPanel();
// jpane.setBounds(0, 75, 680, 255);
jpane.setLayout(null);
jsp = new JScrollPane(jpane, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
jsp.setBounds(0, 75, 680, 255);
jsp.setPreferredSize(new Dimension(680,255));
pane.add(jsp);
My JPanel will be filled with this piece of code...
for(int i = 0; i < Integer.parseInt(spaltenzahl.getText()); i++) {
JTextField spaltennamen_feld = new JTextField();
spaltennamen_feld.setBounds(10, 10+35*i, 150, 25);
spaltennamen_arraylist.add(spaltennamen_feld);
JComboBox<String> datentypen_box = new JComboBox<String>(types);
datentypen_box.setBounds(170, 10+35*i, 150, 25);
datentypen_arraylist.add(datentypen_box);
JComboBox<String> datenzusatz_box = new JComboBox<String>(comb);
datenzusatz_box.setBounds(330, 10+35*i, 100, 25);
datenzusatz_arraylist.add(datenzusatz_box);
jpane.add(spaltennamen_feld);
jpane.add(datentypen_box);
jpane.add(datenzusatz_box);
}
Problem: i can't add a screenshot of my GUI, cause of missing ehr... i forgot the name of this required things here ^_^
But i the real problem is: overflowing content won't be displayed on my JPanel and my ScrollPane does not scroll. Any idea?
Thanks alot :)
Your solution is none of the above. I think that you want to use a JTable, one with three columns, the last two whose editor is a JComboBox.
Edit
For example:
import java.util.Random;
import java.util.Vector;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
public class Foo2 {
private static void createAndShowGui() {
String[] columns = {"Spaltennamen", " Datentypen", "Datenzusatz"};
String[] dataStrings1 = { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" };
String[] dataStrings2 = {"One", "Two", "Three", "Four", "Five"};
Random random = new Random();
DefaultTableModel model = new DefaultTableModel(columns, 0);
int spaltenzahl = 10; // this can change
for (int i = 0; i < spaltenzahl; i++) {
Vector<String> rowData = new Vector<>();
rowData.add("Row Number " + (i + 1));
rowData.add(dataStrings1[random.nextInt(dataStrings1.length)]);
rowData.add(dataStrings2[random.nextInt(dataStrings2.length)]);
model.addRow(rowData);
}
JTable table = new JTable(model);
table.getColumn(columns[1]).setCellEditor(new DefaultCellEditor(new JComboBox<>(dataStrings1)));
table.getColumn(columns[2]).setCellEditor(new DefaultCellEditor(new JComboBox<>(dataStrings2)));
JScrollPane scrollPane = new JScrollPane(table);
JFrame frame = new JFrame("Foo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(scrollPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
A GUI with no white space appears 'crowded'. How can I provide white space without resorting to explicitly setting the position or size of components?
Using various LayoutManagers one can provide spacing between various components.
1.) BorderLayout :
Overloaded Constructor : BorderLayout(int horizontalGap, int verticalGap)
Getter and setter methods
For Horizontal Spacing : BorderLayout.getHgap() and BorderLayout.setHgap(int hgap)
For Vertical Spacing : BorderLayout.getVgap() and BorderLayout.setVgap()
2.) FlowLayout :
Overloaded Constructor : FlowLayout(int align, int hgap, int vgap)
Getter and setter methods
For Horizontal Spacing : FlowLayout.getHgap() and FlowLayout.setHgap(int hgap)
For Vertical Spacing : FlowLayout.getVgap() and FlowLayout.setVgap()
3.) GridLayout :
Overloaded Constructor : GridLayout(int rows, int columns, int hgap, int vgap)
Getter and setter methods
For Horizontal Spacing : GridLayout.getHgap() and GridLayout.setHgap(int hgap)
For Vertical Spacing : GridLayout.getVgap() and GridLayout.setVgap()
4.) GridBagLayout :
GridBagConstraints.insets
5.) CardLayout (example) :
CardLayout(int hGap, int vGap)
Example to display all constructors in action :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class LayoutExample {
private final int hGap = 5;
private final int vGap = 5;
private String[] borderConstraints = {
BorderLayout.PAGE_START,
BorderLayout.LINE_START,
BorderLayout.CENTER,
BorderLayout.LINE_END,
BorderLayout.PAGE_END
};
private JButton[] buttons;
private GridBagConstraints gbc;
private JPanel borderPanel;
private JPanel flowPanel;
private JPanel gridPanel;
private JPanel gridBagPanel;
private JPanel cardPanel;
public LayoutExample() {
buttons = new JButton[16];
gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.FIRST_LINE_START;
gbc.insets = new Insets(hGap, vGap, hGap, vGap);
}
private void displayGUI() {
JFrame frame = new JFrame("Layout Example");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel contentPane = new JPanel(
new GridLayout(0, 1, hGap, vGap));
contentPane.setBorder(
BorderFactory.createEmptyBorder(hGap, vGap, hGap, vGap));
borderPanel = new JPanel(new BorderLayout(hGap, vGap));
borderPanel.setBorder(
BorderFactory.createTitledBorder("BorderLayout"));
borderPanel.setOpaque(true);
borderPanel.setBackground(Color.WHITE);
for (int i = 0; i < 5; i++) {
buttons[i] = new JButton(borderConstraints[i]);
borderPanel.add(buttons[i], borderConstraints[i]);
}
contentPane.add(borderPanel);
flowPanel = new JPanel(new FlowLayout(
FlowLayout.CENTER, hGap, vGap));
flowPanel.setBorder(
BorderFactory.createTitledBorder("FlowLayout"));
flowPanel.setOpaque(true);
flowPanel.setBackground(Color.WHITE);
for (int i = 5; i < 8; i++) {
buttons[i] = new JButton(Integer.toString(i));
flowPanel.add(buttons[i]);
}
contentPane.add(flowPanel);
gridPanel = new JPanel(new GridLayout(2, 2, hGap, vGap));
gridPanel.setBorder(
BorderFactory.createTitledBorder("GridLayout"));
gridPanel.setOpaque(true);
gridPanel.setBackground(Color.WHITE);
for (int i = 8; i < 12; i++) {
buttons[i] = new JButton(Integer.toString(i));
gridPanel.add(buttons[i]);
}
contentPane.add(gridPanel);
gridBagPanel = new JPanel(new GridBagLayout());
gridBagPanel.setBorder(
BorderFactory.createTitledBorder("GridBagLayout"));
gridBagPanel.setOpaque(true);
gridBagPanel.setBackground(Color.WHITE);
buttons[12] = new JButton(Integer.toString(12));
addComp(gridBagPanel, buttons[12], 0, 0, 1, 1
, GridBagConstraints.BOTH, 0.33, 0.5);
buttons[13] = new JButton(Integer.toString(13));
addComp(gridBagPanel, buttons[13], 1, 0, 1, 1
, GridBagConstraints.BOTH, 0.33, 0.5);
buttons[14] = new JButton(Integer.toString(14));
addComp(gridBagPanel, buttons[14], 0, 1, 2, 1
, GridBagConstraints.BOTH, 0.66, 0.5);
buttons[15] = new JButton(Integer.toString(15));
addComp(gridBagPanel, buttons[15], 2, 0, 1, 2
, GridBagConstraints.BOTH, 0.33, 1.0);
contentPane.add(gridBagPanel);
cardPanel = new JPanel(new CardLayout(hGap, vGap));
cardPanel.setBorder(
BorderFactory.createTitledBorder("CardLayout"));
cardPanel.setOpaque(true);
cardPanel.setBackground(Color.WHITE);
cardPanel.add(getPanel(Color.BLUE));
cardPanel.add(getPanel(Color.GREEN));
contentPane.add(cardPanel);
frame.setContentPane(contentPane);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel getPanel(Color bColor) {
JPanel panel = new JPanel(new FlowLayout(
FlowLayout.CENTER, hGap, vGap));
panel.setOpaque(true);
panel.setBackground(bColor.darker().darker());
JButton swapperButton = new JButton("Next");
swapperButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent ae) {
CardLayout cardLayout = (CardLayout) cardPanel.getLayout();
cardLayout.next(cardPanel);
}
});
panel.add(swapperButton);
return panel;
}
private void addComp(JPanel panel, JComponent comp
, int x, int y, int gWidth
, int gHeight, int fill
, double weightx, double weighty) {
gbc.gridx = x;
gbc.gridy = y;
gbc.gridwidth = gWidth;
gbc.gridheight = gHeight;
gbc.fill = fill;
gbc.weightx = weightx;
gbc.weighty = weighty;
panel.add(comp, gbc);
}
public static void main(String[] args) {
Runnable runnable = new Runnable(){
#Override
public void run() {
new LayoutExample().displayGUI();
}
};
EventQueue.invokeLater(runnable);
}
}
OUTPUT :
There are a number of ways in a Swing GUI to provide a separation between components, and white space around components:
JToolBar has the methods addSeparator() & addSeparator(Dimension).
JMenu uses a spacing component better suited to menus, available through addSeparator().
But more generally, look to:
The spacing as can be defined in the layout constructors.
Borders.
Here is an example of using the layout separator hGap & vGap values & borders (specifically an EmptyBorder) to provide 'white' (actually shown as red to make it very obvious) space. Adjust the spinners to see the result.
import java.awt.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.event.*;
public class WhiteSpace {
private JPanel gui = null;
private BorderLayout mainLayout =
new BorderLayout(0, 0);
private final FlowLayout buttonLayout =
new FlowLayout(FlowLayout.CENTER, 0, 0);
private final JPanel buttonPanel = new JPanel(buttonLayout);
private final SpinnerNumberModel hModel =
new SpinnerNumberModel(0, 0, 15, 1);
private final SpinnerNumberModel vModel =
new SpinnerNumberModel(0, 0, 15, 1);
private final SpinnerNumberModel hBorderModel =
new SpinnerNumberModel(0, 0, 15, 1);
private final SpinnerNumberModel vBorderModel =
new SpinnerNumberModel(0, 0, 15, 1);
private ChangeListener changeListener;
public Container getGui() {
if (gui == null) {
gui = new JPanel(mainLayout);
gui.setBackground(Color.RED);
JTree tree = new JTree();
tree.setVisibleRowCount(10);
for (int ii = tree.getRowCount(); ii > -1; ii--) {
tree.expandRow(ii);
}
gui.add(new JScrollPane(
tree,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER),
BorderLayout.LINE_START);
gui.add(new JScrollPane(new JTextArea(10, 30)));
gui.add(buttonPanel, BorderLayout.PAGE_START);
changeListener = (ChangeEvent e) -> {
int hGap = hModel.getNumber().intValue();
int vGap = vModel.getNumber().intValue();
int hBorder = hBorderModel.getNumber().intValue();
int vBorder = vBorderModel.getNumber().intValue();
adjustWhiteSpace(hGap, vGap, hBorder, vBorder);
};
addModel("H Gap", hModel);
addModel("V Gap", vModel);
addModel("H Border", hBorderModel);
addModel("V Border", vBorderModel);
}
return gui;
}
private void addModel(String label, SpinnerNumberModel model) {
buttonPanel.add(new JLabel(label));
final JSpinner spinner = new JSpinner(model);
spinner.addChangeListener(changeListener);
buttonPanel.add(spinner);
}
private void adjustWhiteSpace(
int hGap, int vGap, int hBorder, int vBorder) {
mainLayout.setHgap(hGap);
mainLayout.setVgap(vGap);
buttonLayout.setHgap(hGap);
gui.setBorder(new EmptyBorder
(vBorder, hBorder, vBorder, hBorder));
Container c = gui.getTopLevelAncestor();
if (c instanceof Window) {
Window w = (Window) c;
w.pack();
}
}
public static void main(String[] args) {
Runnable r = () -> {
WhiteSpace ws = new WhiteSpace();
Container gui1 = ws.getGui();
JFrame f = new JFrame("White (OK Red) Space");
f.add(gui1);
f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
f.setLocationByPlatform(true);
f.setResizable(false);
f.pack();
f.setVisible(true);
};
SwingUtilities.invokeLater(r);
}
}
When you use BoxLayout, Box.createVerticalGlue() method can help you to make some white space.
Another method is BorderFactory.createEmptyBorder(int top, int left, int bottom, int right). It can help you to make some white space around component.
Thanks for Andrew Thompson's remind.I've revised BoxLayout in recent days and I find that Box.createVerticalGlue() can add some white space depend on the panel's size and you can not set the explicit pixel value of the length of white space.But Box.createVerticalStrut() can do that. Here is a MCTaRE and show the effect of those two methods.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import javax.swing.event.*;
public class WhiteSpace extends JFrame{
static WhiteSpace whiteSpace;
DemoPanel demoPanel;
boolean withGlue;
JSpinner spinner;
public WhiteSpace(){
initialWindow();
demoPanel = new DemoPanel();
ActionPanel actionPanel = new ActionPanel();
setLayout(new BorderLayout());
getContentPane().add(actionPanel,BorderLayout.NORTH);
getContentPane().add(demoPanel,BorderLayout.CENTER);
setVisible(true);
}
public void initialWindow(){
setSize(220, 300);
setTitle("White Space");
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
//Show the window in the middle of the screen
}
/**
* #param args
*/
public static void main(String[] args) {
Runnable runnable = new Runnable() {
#Override
public void run() {
whiteSpace = new WhiteSpace();
}
};
SwingUtilities.invokeLater(runnable);
}
class DemoPanel extends JPanel{
//Show the vertical white space between label1 and label2
JLabel label1;
JLabel label2;
public void initialDemoPanel(){
setBorder(BorderFactory.createTitledBorder(getBorder(), "DemoPanel", TitledBorder.LEADING, TitledBorder.TOP, new Font("Default",Font.PLAIN,10), Color.gray));
setLayout(new BoxLayout(this, BoxLayout.Y_AXIS));
label1 = new JLabel("This is first line");
label2 = new JLabel("This is second line");
}
public DemoPanel(){
initialDemoPanel();
add(label1);
if(withGlue){
add(Box.createVerticalGlue());
}
add(label2);
}
public DemoPanel(int strutValue){
initialDemoPanel();
add(label1);
add(Box.createVerticalStrut(strutValue));
add(label2);
}
}
class ActionPanel extends JPanel{
public ActionPanel(){
setBorder(BorderFactory.createTitledBorder(getBorder(), "ActionPanel", TitledBorder.LEADING, TitledBorder.TOP, new Font("Default",Font.PLAIN,10), Color.gray));
setLayout(new BoxLayout(this,BoxLayout.X_AXIS));
JRadioButton glueButton = new JRadioButton("With Glue");
glueButton.addActionListener(new glueButtonListener());
add(glueButton);
add(Box.createHorizontalStrut(10));
//To create horizontal white space
JLabel strutLabel = new JLabel("Strut Value");
add(strutLabel);
spinner = new JSpinner(new SpinnerNumberModel(0,0,50,1));
spinner.addChangeListener(new spinnerListener());
add(spinner);
//public SpinnerNumberModel(Number value,Comparable minimum,Comparable maximum,Number stepSize)
}
}
class glueButtonListener implements ActionListener{
#Override
public void actionPerformed(ActionEvent e) {
spinner.setValue(new Integer(0));
withGlue = (withGlue == true ? false:true);
whiteSpace.getContentPane().remove(demoPanel);
demoPanel = new DemoPanel();
whiteSpace.getContentPane().add(demoPanel,BorderLayout.CENTER);
whiteSpace.getContentPane().validate();
}
}
class spinnerListener implements ChangeListener{
#Override
public void stateChanged(ChangeEvent e) {
int strutValue = (Integer) spinner.getValue();
whiteSpace.getContentPane().remove(demoPanel);
demoPanel = new DemoPanel(strutValue);
whiteSpace.getContentPane().add(demoPanel,BorderLayout.CENTER);
whiteSpace.getContentPane().validate();
}
}
}
Box.createHorizontalGlue() and Box.createHorizontalStrut(int height) can be used too. Besides, Box.createRigidArea(Dimension d) has the ability too create white space too.
MigLayout has multiple ways of creating space. (A space is called a gap in this layout.)
Gaps can be created at the highest level with layout constraints, it is possible to
create gaps between rows and column and gaps can be also set between individual
components with component constraints. There are also specific gaps around the borders
of a container called insets which have their own specific keyword to be set.
The following example creates all these kinds of gaps:
package com.zetcode;
import java.awt.EventQueue;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import net.miginfocom.swing.MigLayout;
public class MigLayoutGaps2 extends JFrame {
public MigLayoutGaps2() {
initUI();
setTitle("Gaps");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
}
private void initUI() {
JPanel base = new JPanel(new MigLayout("flowy, ins 30, gap 15"));
setContentPane(base);
JPanel pnl1 = new JPanel();
pnl1.setBorder(
BorderFactory.createTitledBorder("Grid gaps")
);
pnl1.setLayout(new MigLayout("gap 5 5, ins 10, wrap 3"));
pnl1.add(new JButton("1"));
pnl1.add(new JButton("2"));
pnl1.add(new JButton("3"));
pnl1.add(new JButton("4"));
pnl1.add(new JButton("5"));
pnl1.add(new JButton("6"));
JPanel pnl2 = new JPanel();
pnl2.setBorder(
BorderFactory.createTitledBorder("Column gaps")
);
pnl2.setLayout(new MigLayout("wrap 3", "[]10[]"));
JLabel lbl1 = new JLabel();
lbl1.setBorder(
BorderFactory.createEtchedBorder()
);
JLabel lbl2 = new JLabel();
lbl2.setBorder(
BorderFactory.createEtchedBorder()
);
JLabel lbl3 = new JLabel();
lbl3.setBorder(
BorderFactory.createEtchedBorder()
);
pnl2.add(lbl1, "w 40, h 110");
pnl2.add(lbl2, "w 40, h 110");
pnl2.add(lbl3, "w 40, h 110");
JPanel pnl3 = new JPanel();
pnl3.setBorder(
BorderFactory.createTitledBorder("Row gaps")
);
pnl3.setLayout(new MigLayout("wrap", "", "[]15[]"));
JLabel lbl4 = new JLabel();
lbl4.setBorder(
BorderFactory.createEtchedBorder()
);
JLabel lbl5 = new JLabel();
lbl5.setBorder(
BorderFactory.createEtchedBorder()
);
JLabel lbl6 = new JLabel();
lbl6.setBorder(
BorderFactory.createEtchedBorder()
);
pnl3.add(lbl4, "w 150, h 20");
pnl3.add(lbl5, "w 150, h 20");
pnl3.add(lbl6, "w 150, h 20");
JPanel pnl4 = new JPanel();
pnl4.setBorder(
BorderFactory.createTitledBorder("Component gaps")
);
pnl4.setLayout(new MigLayout());
pnl4.add(new JLabel("Name:"), "gapright 5");
pnl4.add(new JTextField(10), "gapbottom 20, gaptop 20");
base.add(pnl1);
base.add(pnl2);
base.add(pnl3);
base.add(pnl4);
pack();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
MigLayoutGaps2 ex = new MigLayoutGaps2();
ex.setVisible(true);
}
});
}
}
We have four panels in the layout. Each of this panels has a MigLayout manager.
JPanel base = new JPanel(new MigLayout("flowy, ins 30, gap 15"));
This line creates container insets and vertical gaps between panels.
pnl1.setLayout(new MigLayout("gap 5 5, ins 10, wrap 3"));
Here we apply gaps for the whole grid structure and also set container gaps.
pnl2.setLayout(new MigLayout("wrap 3", "[]10[]"));
This line creates gaps between columns.
pnl3.setLayout(new MigLayout("wrap", "", "[]15[]"));
Row gaps are defined with this code.
pnl4.add(new JLabel("Name:"), "gapright 5");
pnl4.add(new JTextField(10), "gapbottom 20, gaptop 20");
Finally, it is possible to create gaps between individual components.
JGoodies FormLayout.
Author Karsten Lentzsch has a collection of presentations on UI design. In particular this PDF speaks to the need for aesthetic whitespace. Adding meaningful space while also paying attention to clutter separates the wheat from the chaff.
Whenever I have this issue, I just use JPanels. For example in a GridLayout:
JFrame frame = new JFrame;
frame.setLayout(new GridLayout(2, 0));
//We want the bottom left to be blank
frame.add(new JLabel("Top Left"));
frame.add(new JLabel("Top Right"));
//This is the position we want empty
frame.add(new JPanel());
//Now we can continue with the rest of the script
In my project, I use Swing controls. I had used a label together with a button group, but there is an unwanted line. Please help. There is a label associated with each radio button group. The unwanted line is there.how to add the labels and corresponding radio button group to the same panel
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
//import java.util.Arrays;
public class Online extends JFrame {
static JRadioButton[] choice = new JRadioButton[6];
JFrame jtfMainFrame, jtfMainFrame1;
public void createWindow() {
jtfMainFrame = new JFrame("Online Examination");
jtfMainFrame.setSize(800, 500);
jtfMainFrame.setLocation(200, 150);
jtfMainFrame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
JPanel pa = new JPanel();
JPanel panlabels = new JPanel(new GridLayout(0, 1, 0, 60));
JPanel pancontrols = new JPanel(new GridLayout(0, 1, 0, 60));
JPanel panEast = new JPanel();
JPanel pan = new JPanel(new FlowLayout());
JLabel qLabel = new JLabel("Question.");
qLabel.setOpaque(true);
qLabel.setForeground(Color.blue);
qLabel.setBackground(Color.lightGray);
JLabel aLabel = new JLabel("Question.");
aLabel.setOpaque(true);
aLabel.setForeground(Color.blue);
aLabel.setBackground(Color.lightGray);
JLabel bLabel = new JLabel("a.");
bLabel.setOpaque(true);
bLabel.setForeground(Color.blue);
bLabel.setBackground(Color.lightGray);
JLabel cLabel = new JLabel("b.");
cLabel.setOpaque(true);
cLabel.setForeground(Color.blue);
cLabel.setBackground(Color.lightGray);
JLabel dLabel = new JLabel("c.");
dLabel.setOpaque(true);
dLabel.setForeground(Color.blue);
dLabel.setBackground(Color.lightGray);
JLabel eLabel = new JLabel("d.");
eLabel.setOpaque(true);
eLabel.setForeground(Color.blue);
eLabel.setBackground(Color.lightGray);
panlabels.add(aLabel, BorderLayout.WEST);
panlabels.add(bLabel, BorderLayout.CENTER);
panlabels.add(cLabel, BorderLayout.CENTER);
panlabels.add(dLabel, BorderLayout.CENTER);
panlabels.add(eLabel, BorderLayout.CENTER);
//panlabels.add(fLabel, BorderLayout.WEST);
//fLabel.setVisible(false);
JLabel ques = new JLabel("q");
ques.setBackground(Color.red);
choice[1] = new JRadioButton("a");
choice[1].setBackground(Color.red);
choice[2] = new JRadioButton("b");
choice[2].setBackground(Color.red);
choice[3] = new JRadioButton("c");
choice[3].setBackground(Color.red);
choice[4] = new JRadioButton("d");
choice[4].setBackground(Color.red);
ButtonGroup bGroup = new ButtonGroup();
pancontrols.add(ques, BorderLayout.WEST);
for (int i = 1; i < 5; i++) {
// pancontrols.add(aLabel,BorderLayout.WEST);
bGroup.add(choice[i]);
pancontrols.add(choice[i], BorderLayout.WEST);
}
choice[4].setVisible(true);
panEast.add("West", panlabels);
panEast.add("West", pancontrols);
pa.add("Center", panEast);
pa.setBorder(BorderFactory.createTitledBorder(
BorderFactory.createEtchedBorder(), "Select your answer"));
//getContentPane().add(label);
//to be deleted pa.add("South", pan);
pa.setBackground(Color.pink);
jtfMainFrame.add(pa);
jtfMainFrame.setExtendedState(Frame.MAXIMIZED_BOTH);
jtfMainFrame.setVisible(true);
}
public static void main(String[] args) {
Online r = new Online();
r.createWindow();
}
}
First, your naming convention for the choice labels is off. qLabel="questions", aLabel="questions", bLabel="a", cLabel="b", etc. I would suggest you fix that to eliminate confusion and make your code more readable (ie only have one label that is a question).
Second, your use of panEast.add("West",panlabels); and the other two statements is generally not suggested. Read up on BorderLayout to find the more accepted method of doing this:
http://docs.oracle.com/javase/tutorial/uiswing/layout/border.html
As for your problem, I have rewritten your code so things do line up, I will try to point out what I commented out to help:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
//import java.util.Arrays;
public class Online extends JFrame {
static JRadioButton[] choice = new JRadioButton[6];
JFrame jtfMainFrame, jtfMainFrame1;
public void createWindow() {
jtfMainFrame = new JFrame("Online Examination");
jtfMainFrame.setSize(800, 500);
jtfMainFrame.setLocation(200, 150);
jtfMainFrame.addWindowListener(new WindowAdapter() {
#Override
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
JPanel pa = new JPanel();
//JPanel panlabels = new JPanel(new GridLayout(0, 1, 0, 60));
JPanel pancontrols = new JPanel(new GridLayout(0, 2, 0, 60));
JPanel panEast = new JPanel();
JPanel pan = new JPanel(new BorderLayout());
JLabel qLabel = new JLabel("Question.");
qLabel.setOpaque(true);
qLabel.setForeground(Color.blue);
qLabel.setBackground(Color.lightGray);
JLabel aLabel = new JLabel("Question.");
aLabel.setOpaque(true);
aLabel.setForeground(Color.blue);
aLabel.setBackground(Color.lightGray);
JLabel bLabel = new JLabel("a.");
bLabel.setOpaque(true);
bLabel.setForeground(Color.blue);
bLabel.setBackground(Color.lightGray);
JLabel cLabel = new JLabel("b.");
cLabel.setOpaque(true);
cLabel.setForeground(Color.blue);
cLabel.setBackground(Color.lightGray);
JLabel dLabel = new JLabel("c.");
dLabel.setOpaque(true);
dLabel.setForeground(Color.blue);
dLabel.setBackground(Color.lightGray);
JLabel eLabel = new JLabel("d.");
eLabel.setOpaque(true);
eLabel.setForeground(Color.blue);
eLabel.setBackground(Color.lightGray);
//panlabels.add(fLabel, BorderLayout.WEST);
//fLabel.setVisible(false);
JLabel ques = new JLabel("q");
ques.setBackground(Color.red);
choice[1] = new JRadioButton("a");
choice[1].setBackground(Color.red);
choice[2] = new JRadioButton("b");
choice[2].setBackground(Color.red);
choice[3] = new JRadioButton("c");
choice[3].setBackground(Color.red);
choice[4] = new JRadioButton("d");
choice[4].setBackground(Color.red);
ButtonGroup bGroup = new ButtonGroup();
//pancontrols.add(new JLabel(""));
pancontrols.add(ques, BorderLayout.WEST);
for (int i = 1; i < 5; i++) {
// pancontrols.add(aLabel,BorderLayout.WEST);
bGroup.add(choice[i]);
}
pancontrols.add(qLabel);
pancontrols.add(ques);
pancontrols.add(bLabel);
pancontrols.add(choice[1]);
pancontrols.add(cLabel);
pancontrols.add(choice[2]);
pancontrols.add(dLabel);
pancontrols.add(choice[3]);
pancontrols.add(eLabel);
pancontrols.add(choice[4]);
pancontrols.setSize(400,200);
choice[4].setVisible(true);
pa.add(pancontrols);
pa.setBorder(BorderFactory.createTitledBorder(
BorderFactory.createEtchedBorder(), "Select your answer"));
//getContentPane().add(label);
//to be deleted pa.add("South", pan);
pa.setBackground(Color.pink);
jtfMainFrame.add(pa);
jtfMainFrame.setExtendedState(Frame.MAXIMIZED_BOTH);
jtfMainFrame.setVisible(true);
}
public static void main(String[] args) {
Online r = new Online();
r.createWindow();
}
}
Basically, I removed your unnecessary panels. the only panel you add stuff to now is the pancontrols panel. I changed it to new JPanel(new Gridlayout(0,2,0,60)). With the two column GridLayout you will always have things line up bound wise, due to GridLayout making everything the same size.
Lastly I pulled the adding of choices[] from the loop and did that along with the labels to make sure things line up. I removed all the panels being added except the pancontrols being added to pa, which I assume you want to add more question panels to pa in that case. That covers your question in particular, but there is quite a lot of stuff you should do (ie use choice[0] for example, eliminate unused labels and panels, etc.)
I want to add JTable into JPanel whose layout is null. JPanel contains other components. I have to add JTable at proper position.
Nested/Combination Layout Example
The Java Tutorial has comprehensive information on using layout managers. See the Laying Out Components Within a Container lesson for further details.
One aspect of layouts that is not covered well by the tutorial is that of nested layouts, putting one layout inside another to get complex effects.
The following code puts a variety of components into a frame to demonstrate how to use nested layouts. All the layouts that are explicitly set are shown as a titled-border for the panel on which they are used.
Notable aspects of the code are:
There is a combo-box to change PLAF (Pluggable Look and Feel) at run-time.
The GUI is expandable to the user's need.
The image in the bottom of the split-pane is centered in the scroll-pane.
The label instances on the left are dynamically added using the button.
Nimbus PLAF
NestedLayoutExample.java
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
import javax.swing.border.TitledBorder;
/** A short example of a nested layout that can change PLAF at runtime.
The TitledBorder of each JPanel shows the layouts explicitly set.
#author Andrew Thompson
#version 2011-04-12 */
class NestedLayoutExample {
public static void main(String[] args) {
Runnable r = new Runnable() {
public void run() {
final JFrame frame = new JFrame("Nested Layout Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JPanel gui = new JPanel(new BorderLayout(5,5));
gui.setBorder( new TitledBorder("BorderLayout(5,5)") );
//JToolBar tb = new JToolBar();
JPanel plafComponents = new JPanel(
new FlowLayout(FlowLayout.RIGHT, 3,3));
plafComponents.setBorder(
new TitledBorder("FlowLayout(FlowLayout.RIGHT, 3,3)") );
final UIManager.LookAndFeelInfo[] plafInfos =
UIManager.getInstalledLookAndFeels();
String[] plafNames = new String[plafInfos.length];
for (int ii=0; ii<plafInfos.length; ii++) {
plafNames[ii] = plafInfos[ii].getName();
}
final JComboBox plafChooser = new JComboBox(plafNames);
plafComponents.add(plafChooser);
final JCheckBox pack = new JCheckBox("Pack on PLAF change", true);
plafComponents.add(pack);
plafChooser.addActionListener( new ActionListener(){
public void actionPerformed(ActionEvent ae) {
int index = plafChooser.getSelectedIndex();
try {
UIManager.setLookAndFeel(
plafInfos[index].getClassName() );
SwingUtilities.updateComponentTreeUI(frame);
if (pack.isSelected()) {
frame.pack();
frame.setMinimumSize(frame.getSize());
}
} catch(Exception e) {
e.printStackTrace();
}
}
} );
gui.add(plafComponents, BorderLayout.NORTH);
JPanel dynamicLabels = new JPanel(new BorderLayout(4,4));
dynamicLabels.setBorder(
new TitledBorder("BorderLayout(4,4)") );
gui.add(dynamicLabels, BorderLayout.WEST);
final JPanel labels = new JPanel(new GridLayout(0,2,3,3));
labels.setBorder(
new TitledBorder("GridLayout(0,2,3,3)") );
JButton addNew = new JButton("Add Another Label");
dynamicLabels.add( addNew, BorderLayout.NORTH );
addNew.addActionListener( new ActionListener(){
private int labelCount = 0;
public void actionPerformed(ActionEvent ae) {
labels.add( new JLabel("Label " + ++labelCount) );
frame.validate();
}
} );
dynamicLabels.add( new JScrollPane(labels), BorderLayout.CENTER );
String[] header = {"Name", "Value"};
String[] a = new String[0];
String[] names = System.getProperties().
stringPropertyNames().toArray(a);
String[][] data = new String[names.length][2];
for (int ii=0; ii<names.length; ii++) {
data[ii][0] = names[ii];
data[ii][1] = System.getProperty(names[ii]);
}
DefaultTableModel model = new DefaultTableModel(data, header);
JTable table = new JTable(model);
try {
// 1.6+
table.setAutoCreateRowSorter(true);
} catch(Exception continuewithNoSort) {
}
JScrollPane tableScroll = new JScrollPane(table);
Dimension tablePreferred = tableScroll.getPreferredSize();
tableScroll.setPreferredSize(
new Dimension(tablePreferred.width, tablePreferred.height/3) );
JPanel imagePanel = new JPanel(new GridBagLayout());
imagePanel.setBorder(
new TitledBorder("GridBagLayout()") );
BufferedImage bi = new BufferedImage(
200,200,BufferedImage.TYPE_INT_ARGB);
Graphics2D g = bi.createGraphics();
GradientPaint gp = new GradientPaint(
20f,20f,Color.red, 180f,180f,Color.yellow);
g.setPaint(gp);
g.fillRect(0,0,200,200);
ImageIcon ii = new ImageIcon(bi);
JLabel imageLabel = new JLabel(ii);
imagePanel.add( imageLabel, null );
JSplitPane splitPane = new JSplitPane(
JSplitPane.VERTICAL_SPLIT,
tableScroll,
new JScrollPane(imagePanel));
gui.add( splitPane, BorderLayout.CENTER );
frame.setContentPane(gui);
frame.pack();
frame.setLocationRelativeTo(null);
try {
// 1.6+
frame.setLocationByPlatform(true);
frame.setMinimumSize(frame.getSize());
} catch(Throwable ignoreAndContinue) {
}
frame.setVisible(true);
}
};
SwingUtilities.invokeLater(r);
}
}
Other Screen Shots
Windows PLAF
Mac OS X Aqua PLAF
Ubuntu GTK+ PLAF
Don't use a null layout. Learn to use LayoutManagers:
http://download.oracle.com/javase/tutorial/uiswing/layout/using.html
LayoutManagers allow you to properly handle things window resizing or dynamic component counts. They might seem intimidating at first, but they are worth the effort to learn.
As I can remember, the null layout means an absolute position so it will be pretty hard you to count the X point for your JTable left upper corner location. But if you just want to have all panel components one by one you can use FlowLayout() manager as
JPanel panel=new JPanel(new FlowLayout());
panel.add(new aComponent());
panel.add(new bComponent());
panel.add(new JTable());
or if you need to fill the panel you should use GridLayout() as...
int x=2,y=2;
JPanel panel=new JPanel(new GridLayout(y,x));
panel.add(new aComponent());
panel.add(new bComponent());
panel.add(new JTable());
Good luck
If you are using null layout manager you always need to set the bounds of a component.
That is the problem in your case.
You should do what everyone suggest here and go and use some layout manager believe they save time.
Go and check out the tutorial in #jzd's post.
Enjoy, Boro.
JTable should be added into the JScrollPane which actually should be added into the JPanel.
The JPanel should have some layout manager.
If you don't care about the precision of components size you can use pure BorderLayout and combine it with FlowLayout and GridLayout. if you need precision - use jgoodies FormLayout.
The FormLayout is really tricky one, but you can play a little with WindowBuilder (which is embedded into Eclipse) and a look at the code it generates. It may look complicated but it is just an ignorance.
Good luck.
First, you should seriously consider other Layout managers, for example the BorderLayoutManager (new JPanel(new BorderLayout())) is a good start.
Also when designing your dialog, remember that you can and should nest your layouts: one JPanel inside another JPanel (e.g. a GridLayout inside a BorderLayout). Please note: a 'good' dialog should resize properly, so that if the user resizes your Frame, you want to automatically extend your information objects such as your table, and not show large areas of JPanel background. That's something you cannot achieve with a NullLayout.
But there are probably cases - somewhere in this big world - where a NullLayout is just the thing. So here's an example:
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
public class JTableInNullLayout
{
public static void main(String[] argv) throws Exception {
DefaultTableModel model = new DefaultTableModel(
new String[][] { { "a", "123"} , {"b", "456"} },
new String[] { "name", "value" } );
JTable t = new JTable(model);
JPanel panel = new JPanel(null);
JScrollPane scroll = new JScrollPane(t);
scroll.setBounds( 0, 20, 150, 100 ); // x, y, width, height
panel.add(scroll);
JFrame frame = new JFrame();
frame.add(panel);
frame.setPreferredSize( new Dimension(200,200));
frame.pack();
frame.setVisible(true);
}
}
When a component have a "null" layout, you have to manage the layout by yourself, that means you have to calculate the dimensions and locations for the children of the component to decide where they are drawn. Quite tedious unless it is absolutely necessary.
If you really want that fine-grained control, maybe try GridBagLayout first before going mudding with the UI arrangement.
JPanel panel = new JPanel();
JTable table = new JTable(rowData, colData);
JScrollPane scrollPane = new JScrollPane(table);
panel.add(scrollPane, BorderLayout.CENTER);
panel.setSize(800, 150);
panel.add(table);
panel.setLocationRelativeTo(null);
panel.setVisible(true);
Hope this helps.
JFrame frame = new JFrame("Sample Frame");
frame.setSize(600, 600);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
DefaultTableModel dfm = new DefaultTableModel(data, columnNames);
JTable table = new JTable(dfm);
JScrollPane scrollPane = new JScrollPane(table);
panel.add(scrollPane);
frame.add(panel);
frame.setVisible(true);
table model depends on your requirement
this.setTitle("Sample");
JPanel p = new JPanel(new BorderLayout());
WindowEvent we = new WindowEvent(this, WindowEvent.WINDOW_CLOSED);
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
});
// Create columns names
String columnNames[] = { "FirstCol", "SecondCol",
"ThirdCol", "FourthCol" };
dataModel = new DefaultTableModel();
for (int col = 0; col < columnNames.length; col++) {
dataModel.addColumn(columnNames[col]);
}
// Create a new table instance
table = new JTable(dataModel);
table.setPreferredScrollableViewportSize(new Dimension(200, 120));
table.setFillsViewportHeight(true);
table.setShowGrid(true);
table.setAutoscrolls(true);
// Add the table to a scrolling pane
scrollPane = new JScrollPane(table,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
scrollPane.setPreferredSize(new Dimension(700, 700));
JPanel jpResultPanel = new JPanel();
jpResultPanel.setBorder(BorderFactory.createTitledBorder(
BorderFactory.createEtchedBorder(), "Result",
TitledBorder.CENTER, TitledBorder.TOP));
jpResultPanel.add(scrollPane);
add(jpResultPanel);
pack();
setSize(720, 720);
setVisible(true);
Try this.
You can make use of the following code. To add JTable to JPanel.
JPanel panel = new JPanel();
this.setContentPane(panel);
panel.setLayout(null);
String data[][] = {{"1.", "ABC"}, {"2.", "DEF"}, {"3.", "GHI" }};
String col[] = {"Sr. No", "Name"};
JTable table = new JTable(data,col);
table.setBounds(100, 100, 100, 80);
panel.add(table);
setVisible(true);
setSize(300,300);