I want to stack some JComponents vertically inside a JPanel so they stack at the top and any extra space is at the bottom. I'm using a BoxLayout. The components will each contain a JTextArea that should allow the text to wrap if necessary. So, basically, I want the height of each of these components to be the minimum necessary for displaying the (possibly wrapped) text.
Here's a contained code example of what I'm doing:
import javax.swing.*;
import java.awt.*;
public class TextAreaTester {
public static void main(String[] args){
new TextAreaTester();
}
public TextAreaTester(){
JFrame frame = new JFrame();
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel,BoxLayout.PAGE_AXIS));
panel.setPreferredSize(new Dimension(100,400));
for(int i = 0; i<3; i++){
JPanel item = new JPanel(new BorderLayout());
JTextArea textarea = new JTextArea("this is a line of text I want to wrap if necessary");
textarea.setWrapStyleWord(true);
textarea.setLineWrap(true);
textarea.setMaximumSize( textarea.getPreferredSize() );
item.add(textarea,BorderLayout.NORTH);
panel.add(item);
}
panel.add(Box.createGlue());
frame.add(panel);
frame.setVisible(true);
frame.pack();
}
}
The child JPanels are expanding to fill the vertical space. I tried using glue because I thought that's what glue was for, but it seems to do nothing at all. Any help?
Note: I have found questions that look almost identical, but none with answers I can apply.
One solution: nest JPanels with the outer JPanel using Borderlayout and adding the BoxLayout using JPanel to this one BorderLayout.NORTH, also known as BorderLayout.PAGE_START:
Edit for Kleopatra:
import javax.swing.*;
import java.awt.*;
public class TextAreaTester {
public static void main(String[] args) {
new TextAreaTester();
}
public TextAreaTester() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.PAGE_AXIS));
// panel.setPreferredSize(new Dimension(100,400));
for (int i = 0; i < 3; i++) {
JPanel item = new JPanel(new BorderLayout());
// item.setLayout(new BoxLayout(item,BoxLayout.LINE_AXIS));
JTextArea textarea = new JTextArea(
"this is a line of text I want to wrap if necessary", 3, 35);
textarea.setWrapStyleWord(true);
textarea.setLineWrap(true);
// textarea.setMaximumSize(textarea.getPreferredSize());
// item.setMaximumSize( item.getPreferredSize() );
item.add(new JScrollPane(textarea), BorderLayout.NORTH);
panel.add(item);
}
panel.add(Box.createGlue());
JPanel mainPanel = new JPanel(new BorderLayout()) {
private final int prefW = 100;
private final int prefH = 400;
#Override
public Dimension getPreferredSize() {
return new Dimension(prefW, prefH);
}
};
// mainPanel.setPreferredSize(new Dimension(100, 400));
mainPanel.add(panel, BorderLayout.PAGE_START);
frame.add(mainPanel);
frame.setVisible(true);
// frame.getContentPane().add(jp);
frame.pack();
}
}
Alternatively, you can use Box.Filler. Just replace your call to panel.add(Box.createGlue()) with
panel.add(new Box.Filler(new Dimension(0, 0),
new Dimension(0, Short.MAX_VALUE),
new Dimension(0, Short.MAX_VALUE)));
If you want to achieve the same for a horizontal layout, just use Short.MAX_VALUE for width instead of height in the Dimension call.
Related
I have a parent JPanel with child components which are stacked on another. However they do not resize as I'd like to:
This is how it should be
This is what I get
Code:
public class LayoutTest extends JFrame {
public LayoutTest() {
setVisible(true);
setSize(new Dimension(500, 500));
getContentPane().setLayout(new BoxLayout(getContentPane(), BoxLayout.PAGE_AXIS));
for (int i = 0; i < 2; i++) {
JPanel panel = new JPanel();
panel.setPreferredSize(new Dimension(500, 50));
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
panel.setBackground(Color.red);
getContentPane().add(panel);
}
}
public static void main(String[] args) {
LayoutTest layoutTest = new LayoutTest();
}
}
The problem mainly is that the components resize vertically when they should not. I'd like them to keep their vertical dimension, but they won't. I've tried multiple layouts e.g. GridBagLayout, FlowLayout, BoxLayout, but none of them worked.
My best try has been with BoxLayout:
Simply: container.setLayout(new BoxLayout(container, BoxLayout.PAGE_AXIS);
and then container.add(component1)...
Any help is appreciated.
Working solution by camickr:
public class LayoutTest extends JFrame {
public LayoutTest() {
setVisible(true);
setSize(new Dimension(500, 500));
JPanel container = new JPanel();
container.setLayout(new BoxLayout(container, BoxLayout.PAGE_AXIS));
for (int i = 0; i < 2; i++) {
JPanel panel = new JPanel();
panel.setPreferredSize(new Dimension(500, 50));
panel.setBorder(BorderFactory.createLineBorder(Color.BLACK));
panel.setBackground(Color.red);
container.add(panel, BorderLayout.PAGE_START);
}
getContentPane().add(container, BorderLayout.NORTH);
}
public static void main(String[] args) {
LayoutTest layoutTest = new LayoutTest();
}
}
A BoxLayout will grow components up to there maximum size when space is available.
When you add your panel to the frame, instead of adding it to the CENTER, which would allow the panel to grow, you add it to the PAGE_START which will respect the height:
JPanel north = new JPanel();
north.setLayout( new BoxLayout(north, BoxLayout.PAGE_AXIS) );
// add loop to add panels to the "north" panel
add(north, BorderLayout.PAGE_START);
Another solution is to wrap the panel using a box layout into another panel.
JPanel panel = new JPanel();
panel.setLayout( new BoxLayout(panel. BoxLayout.PAGE_AXIS) );
// create your loop to add child panels
JPanel wrapper = new JPanel(); // uses FlowLayout by default which respects the preferred size.
wrapper.add( panel );
frame.add( wrapper );
I need to add about 600 Images to a Scrollpane, but all the Images are arranged side-by-side
public CollectionPanel(Controller controller)
this.setBackground(Color.white);
this.setLayout(new BorderLayout());
JPanel content = new JPanel();
content.setLayout(new FlowLayout());
JScrollPane scrollPane = new JScrollPane(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
for(int i = 0; i < 100; ++i){
content.add(new Sticker(i+1));
}
scrollPane.setViewportView(content);
this.add(scrollPane, BorderLayout.CENTER);
}
How is it possible to arrange them to make a "linebreak" when they reached the end of the screen?
Have a look at Rob Camick's WrapLayout.
You can resize the frame, and all your components will be reformatted for you. Here's an example usage
import java.awt.*;
import javax.swing.*;
public class TestWrapLayout {
public TestWrapLayout () {
ImageIcon icon = new ImageIcon(getClass().getResource("/resources/stackoverflow2.png"));
JPanel panel = new JPanel(new WrapLayout());
for (int i = 1; i <= 250; i++) {
JLabel iconlabel = new JLabel(icon);
iconlabel.setLayout(new BorderLayout());
JLabel textlabel = new JLabel(String.valueOf(i));
textlabel.setHorizontalAlignment(JLabel.CENTER);
textlabel.setForeground(Color.WHITE);
textlabel.setFont(new Font("impact", Font.PLAIN,20));
iconlabel.add(textlabel);
panel.add(iconlabel);
}
JFrame frame = new JFrame();
frame.add(new JScrollPane(panel));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 300);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
new TestWrapLayout();
}
});
}
}
Use GridLayout instead of FlowLayout that fits the components side by side.
JPanel content = new JPanel();
content.setLayout(new GridLayout(rows,1));
//pass no of rows with just one column
You can try with BoxLayout as well.
JPanel content = new JPanel();
content.setLayout(new BoxLayout(content, BoxLayout.PAGE_AXIS));
Please have a look at Using Layout Managers & A Visual Guide to Layout Managers for more info with working sample codes.
Myself, I would try to keep things as simple as possible by putting images, ImageIcons actually, into a JList which can handle ImageIcons quite well. Give it a horizontal wrap set its visible row count to 0, plop it into a JScrollPane, and there you go.
Can anyone help me. Why is the Label "Current" NOT left aligned in Panel/Frame?
public static void main(String[] args) {
JFrame TFrame = new JFrame("Test DisplayLayout");
TFrame.setResizable(true);
TFrame.setSize(new Dimension(900, 840));
TFrame.setLocationRelativeTo(null);
TFrame.setTitle("DisplayLayout");
TFrame.setVisible(true);
JPanel P = DisplayLayout2();
P.setVisible(true);
P.setOpaque(true);
P.setLayout(new BoxLayout(P, BoxLayout.Y_AXIS));
TFrame.add(P);
TFrame.revalidate();
TFrame.repaint();
}
public static JPanel DisplayLayout2() {
JPanel Panel=new JPanel();
Panel.setVisible(true);
Panel.setOpaque(true);
Panel.setLayout(new BoxLayout(Panel, BoxLayout.Y_AXIS));
Panel.setAlignmentX(Component.LEFT_ALIGNMENT);
JLabel lab = new JLabel("Current");
lab.setHorizontalAlignment(SwingConstants.LEFT);
lab.setForeground(Color.WHITE);
lab.setBackground(Color.PINK);
lab.setOpaque(true);
Panel.add(lab,Component.LEFT_ALIGNMENT);
JPanel posPanel = new JPanel();
JScrollPane scrollPane = new JScrollPane(posPanel,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollPane.setPreferredSize(new Dimension(290, 200));
scrollPane.setOpaque(true);
posPanel.setBackground(Color.YELLOW);
posPanel.setPreferredSize(new Dimension(290, 200));
posPanel.setLayout(new BoxLayout(posPanel, BoxLayout.Y_AXIS));
posPanel.setAlignmentX(Component.LEFT_ALIGNMENT);
Panel.add(scrollPane);
return Panel;
}
This is one of the quirks of the BoxLayout (well, quirk to me, but it is a documented expected behavior of the layout), and I'm forgetting off the top of my head why it does this, but I do know of at least one way around it: put your JLabel into a JPanel that uses FlowLayout.LEFT (or LEADING), and add that to your BoxLayout-using container:
JPanel labPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 0, 0));
labPanel.add(lab);
panel.add(labPanel, Component.LEFT_ALIGNMENT);
Note, that I believe that it has something to do with the JLabel not wanting to expand while the JPanel that encloses it does, but don't quote me on that.
Edit
From the BoxLayout Tutorial:
For a top-to-bottom box layout, the preferred width of the container is that of the maximum preferred width of the children. If the container is forced to be wider than that, BoxLayout attempts to size the width of each component to that of the container's width (minus insets). If the maximum size of a component is smaller than the width of the container, then X alignment comes into play.
You could probably solve this by setting both the JLabel's and the JScrollPane's x-alignment to Component.LEFT_ALIGNMENT. Your current code forgets to set the JScrollPane's x-alignment, and that's where your trouble lies:
scrollPane.setAlignmentX(Component.LEFT_ALIGNMENT);
For example:
import java.awt.*;
import javax.swing.*;
public class Foo2 {
private static void createAndShowGui() {
JLabel topLabel = new JLabel("Top Label", SwingConstants.LEFT);
topLabel.setOpaque(true);
topLabel.setBackground(Color.pink);
JScrollPane scrollpane = new JScrollPane(
Box.createRigidArea(new Dimension(400, 400)),
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
JPanel mainPanel = new JPanel();
mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.PAGE_AXIS));
topLabel.setAlignmentX(Component.LEFT_ALIGNMENT);
mainPanel.add(topLabel);
scrollpane.setAlignmentX(Component.LEFT_ALIGNMENT);
mainPanel.add(scrollpane);
JFrame frame = new JFrame("Foo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
This results in:
Use constant into Component(Left,Right,Center)
Hey guys I wanted to create a JScrollPane but it won't work... and I don't know why... here's my code...
public class test extends JFrame{
public test(){
setSize(1000,600);
}
private static JButton[] remove;
private static JPanel p = new JPanel();
public static void main(String[]args){
p.setLayout(null);
JFrame t=new test();
remove = new JButton[25];
for(int i=0;i<25;i++){
remove[i]=new JButton("Remove");
remove[i].setBounds(243,92+35*i,85,25);
p.add(remove[i]);
}
JScrollPane scrollPane = new JScrollPane(p);
scrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED);
t.add(scrollPane);
t.setVisible(true);
}
Umm and Im pretty sure the frame isn't big enough for these 25 buttons... But if i delete that p.setLayout(null); A horizontal scroll bar will be created automatically... I don't really know what is wrong with my code... Pls help thank you very much!
You need to set p's preferredSize for this to work.
p.setPreferredSize(new Dimension(800, 2000));
Or you could have p extend JPanel and then override the getPreferredSize() method to return the proper dimension.
And I agree -- get rid of your null layouts. Learn about and use the layout managers if you want to use Swing correctly and have robust Swing GUI's.
e.g.,
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Foo extends JFrame {
private static final int BUTTON_COUNT = 25;
public static void main(String[] args) {
JPanel btnPanel = new JPanel(new GridLayout(0, 1, 0, 20));
btnPanel.setBorder(BorderFactory.createEmptyBorder(20, 20, 20, 20));
AbstractAction removeAction = new AbstractAction("Remove") {
#Override
public void actionPerformed(ActionEvent evt) {
JButton src = (JButton) evt.getSource();
JPanel container = (JPanel) src.getParent();
container.remove(src);
container.revalidate();
container.repaint();
}
};
for (int i = 0; i < BUTTON_COUNT; i++) {
JButton removeBtn = new JButton(removeAction);
btnPanel.add(removeBtn);
}
JPanel borderPanel = new JPanel(new BorderLayout());
borderPanel.add(btnPanel, BorderLayout.NORTH);
JScrollPane scrollpane = new JScrollPane(borderPanel,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
scrollpane.setPreferredSize(new Dimension(400, 800));
JFrame frame = new JFrame("Foo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(scrollpane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
The issue is that a scroll pane checks the component inside it for a "preferred size" so a pane with a null layout has a preferred size of (0,0). Which it ignores.
You should do something along the lines of:
p.setPreferredSize(1000,600);
And you should see some scroll bars appear, I'm not sure how accurate they will be though.
I want to create a JInternalFrame with some components in it.
My aim is to design a bash console in Java.
My frame is made of 4 components:
JTextArea included into a JScrollPane
JLabel with the text "Cmd:"
JTextField
JButton with the text "Send"
And I have the following code:
Box box = Box.createHorizontalBox();
box.add(Box.createVerticalStrut(5));
box.add(this.cmd_label);
box.add(Box.createVerticalStrut(5));
box.add(this.cmd_input);
box.add(Box.createVerticalStrut(5));
box.add(this.submit);
box.add(Box.createVerticalStrut(5));
Box mainBox = Box.createVerticalBox();
mainBox.add(Box.createHorizontalStrut(5));
mainBox.add(this.result_scroll);
mainBox.add(Box.createHorizontalStrut(5));
mainBox.add(box);
mainBox.add(Box.createHorizontalStrut(5));
add(mainBox);
So when the frame has not been maximized, I have a correct look:
But when I maximize it, all components are incorrectly located:
So, here is my question: How can I set a weight to the components to fix their location every time, or, how can I fix it?
Thanks.
I think this would be better done with a BorderLayout. In a BorderLayout, the component specified as the center component will expand to fill as much space as possible, and the other components will remain at their preferred sizes.
int hgap = 5;
int vgap = 5;
internalFrame.getContentPane().setLayout(new BorderLayout(hgap, vgap));
internalFrame.getContentPane().add(this.result_scroll, BorderLayout.CENTER);
JPanel bottomPanel = new JPanel();
bottomPanel.add(this.cmd_label);
bottomPanel.add(this.cmd_input);
bottomPanel.add(this.submit);
internalFrame.getContentPane().add(bottomPanel, BorderLayout.SOUTH);
Here try this code, is this behaviour exceptable :
import java.awt.*;
import javax.swing.*;
public class LayoutExample
{
private void createAndDisplayGUI()
{
JFrame frame = new JFrame("LAYOUT EXAMPLE");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel centerPanel = new JPanel();
centerPanel.setLayout(new BorderLayout(5, 5));
centerPanel.setBorder(
BorderFactory.createEmptyBorder(2, 2, 2, 2));
JTextArea tarea = new JTextArea(10, 10);
tarea.setBackground(Color.DARK_GRAY.darker());
tarea.setForeground(Color.WHITE);
tarea.setCaretColor(Color.WHITE);
tarea.setLineWrap(true);
JScrollPane scrollPane = new JScrollPane(tarea);
centerPanel.add(scrollPane, BorderLayout.CENTER);
JPanel footerPanel = new JPanel();
footerPanel.setLayout(new BorderLayout(5, 5));
footerPanel.setBorder(
BorderFactory.createEmptyBorder(2, 2, 2, 2));
JLabel cmdLabel = new JLabel("Cmd : ");
JTextField tfield = new JTextField(10);
JPanel buttonPanel = new JPanel();
buttonPanel.setBorder(
BorderFactory.createEmptyBorder(2, 2, 2, 2));
JButton sendButton = new JButton("SEND");
footerPanel.add(cmdLabel, BorderLayout.LINE_START);
footerPanel.add(tfield, BorderLayout.CENTER);
buttonPanel.add(sendButton);
footerPanel.add(buttonPanel, BorderLayout.LINE_END);
frame.getContentPane().add(centerPanel, BorderLayout.CENTER);
frame.getContentPane().add(footerPanel, BorderLayout.PAGE_END);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new LayoutExample().createAndDisplayGUI();
}
});
}
}
OUTPUT :
Base problem here is what I consider a bug in JTextField's max layout hint: it's unbounded in both horizontal and vertical dimension. The latter is pure nonsense for a component designed for showing a single line of text. To fix, subclass and let it return its pref for the height, like:
JTextField cmdInput = new JTextField() {
#Override
public Dimension getMaximumSize() {
Dimension max = super.getMaximumSize();
max.height = getPreferredSize().height;
return max;
}
};
As BoxLayout respects maxSize, the excess height now will be given to the top box only.
On the long run, consider switching to a third party manager which allows fine-tuning in a all-in-one-panel approach. Yeah, here comes my current favourite: MigLayout. Compare the following lines to all the nesting and border tricks above and have fun :-)
MigLayout layout = new MigLayout("wrap 3, debug",
"[][grow, fill][]", // 3 columns, middle column filled and allows growing
"[grow, fill][]"); // two rows, first filled and allows growing
JComponent content = new JPanel(layout);
// the scrollPane in the first row spanning all columns
// and growing in both directions
content.add(new JScrollPane(new JTextArea(20, 20)), "span, grow");
// auto-wrapped to first column in second row
content.add(new JLabel("Cmd:"));
content.add(new JTextField());
content.add(new JButton("Submit"));