Set JPanel Size to No Larger Than Element it Contains - java

I’m trying to get a JPanel to be no taller than the text in the single JLabel it contains. Here’s some simple example code stripped down to just the essential issue:
import java.awt.*;
import javax.swing.*;
public class MinimumSpacing {
private static void createAndShowGUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 250);
JPanel pane0 = new JPanel(new GridLayout(0,1,0,0));
JPanel pane1 = new JPanel(new GridLayout(0,1,0,0));
JPanel pane2 = new JPanel(new GridLayout(0,1,0,0));
pane1.add(new JLabel("This is line #1.", JLabel.CENTER));
pane2.add(new JLabel("This is line #2.", JLabel.CENTER));
pane2.add(new JLabel("This is line #3.", JLabel.CENTER));
pane2.add(new JLabel("This is line #4.", JLabel.CENTER));
pane2.add(new JLabel("This is line #5.", JLabel.CENTER));
pane0.add(pane1);
pane0.add(pane2);
frame.add(pane0);
frame.setVisible(true);
}
public static void main(String[] args) {
try {
UIManager.setLookAndFeel(
"com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel"
);
} catch (Exception exc) {
//
}
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowGUI();
}
});
}
}
This is the result I get:
What I want is for “line #1” to be at the top of the frame with the other 4 lines immediately under it. What’s the best way to shrink the size of pane1 to make this happen?
Any help would be appreciated.

Don't use a GridLayout. A GridLayout will always resize each component to be of equal size.
Maybe you should use a vertical BoxLayout.
Read the section from the Swing tutorial on Layout Managers for more information and working examples.

As already indicated, you should consider to use a BoxLayout. Here is how to do this:
private static void createAndShowGUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(300, 250);
JPanel pane0 = new JPanel();
pane0.setLayout(new BoxLayout(pane0, BoxLayout.Y_AXIS));
pane0.add(new JLabel("This is line #1.", JLabel.CENTER));
pane0.add(new JLabel("This is line #2.", JLabel.CENTER));
pane0.add(new JLabel("This is line #3.", JLabel.CENTER));
pane0.add(new JLabel("This is line #4.", JLabel.CENTER));
pane0.add(new JLabel("This is line #5.", JLabel.CENTER));
frame.add(pane0);
frame.setVisible(true);
}

Related

Java Swing GUI JLabel Not Showing

I am trying to write a Title for the main menu of my program, by using a JLabel, but it doesn't seem to appear on my screen.
import javax.swing.*;
public class GUI {
public GUI() {
JFrame frame = new JFrame();
JPanel panel = new JPanel();
panel.setBorder(BorderFactory.createEmptyBorder(30,30,10,30));
panel.setLayout(new GridLayout());
frame.add(panel, BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("Title");
frame.pack();
frame.setSize(854,560);
frame.setVisible(true);
JLabel title = new JLabel();
title.setText("Title");
//title.setSize();
title.setVisible(true);
}
public static void main(String[] args) {
new GUI();
}
}
What am I doing wrong and how could I change the position of the Text if I manage to make it visible?
And I also want to add a button to go to the next page so if you could tell me how to do that too that would be great.
I would quickly and untested say that you are adding the label after you set the frame visible.
Do it before. Else you would have to revalidate and repaint the frame
As I can see in your code you are not adding title in panel. As a quick solution put panel.add(title); after title.setVisible(true); line in your code, it will display the label.
JFrame frame = new JFrame();
JPanel panel = new JPanel();
panel.setBorder(BorderFactory.createEmptyBorder(30,30,10,30));
panel.setLayout(new GridLayout());
frame.add(panel, BorderLayout.CENTER);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("Title");
frame.pack();
frame.setSize(854,560);
frame.setVisible(true);
JLabel title = new JLabel();
title.setText("Title");
//title.setSize();
title.setVisible(true);
panel.add(title); //<---- this one line will diaplay label in GUI

Multiple JPanels - All buttons same size

I have a a main panel that contains multiple panels inside. Each 'children' panel contains one (or more) JButtons. Since I am displaying all the panels at the same time, I would like to make all the buttons the same size (to have consistency).
This code illustrates my problem:
public class Test
{
public static void main(String[] args)
{
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(new Dimension(200, 200));
// 1st Panel
JPanel panel1 = new JPanel(new MigLayout());
panel1.add(new JButton("button in panel 1"));
// 2nd Panel
JPanel panel2 = new JPanel(new MigLayout());
panel2.add(new JButton("2nd button"));
JPanel parent = new JPanel(new MigLayout("wrap"));
parent.add(panel1, "pushx, growx");
parent.add(new JSeparator(), "pushx, growx");
parent.add(panel2, "pushx, growx");
f.add(parent);
f.setVisible(true);
}
}
The size of the "button in panel 1" is different from the button in the other panel. Is there an 'easy' way to set their size using the layout? (Hardcoding the size is NOT an option).
I think you didn't read the document carefully, to demonstrate the use I have written a code. You should not copy the same snippet showed in that link. They have specified that the component you have updating must be passed into updateComponentTreeUI() method. You can replace the size by replacing the "large" with "small" or "mini".
import javax.swing.*;
import java.awt.*;
public class Demo {
/**
* #param args
*/
JFrame frame ;
JButton btn;
public Demo()
{
frame = new JFrame("Example");
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400,400);
frame.setLayout(new FlowLayout());
btn = new JButton("Example");
btn.putClientProperty("JComponent.sizeVariant", "large");
SwingUtilities.updateComponentTreeUI(btn);
frame.add(btn);
frame.setVisible(true);
}
public static void main(String[] args) {
// TODO Auto-generated method stub
try
{
UIManager.setLookAndFeel("com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
}
catch(Exception e)
{
e.printStackTrace();
}
Demo d = new Demo();
}
}

Java BoxLayout alignment issue

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)

JButtons in JPanel in another JPanel

Is it possible to add a JPanel with JButtons to a Split JPanel? Right now, I have the JPanel with JButtons added to a JFrame, but I want it on a JPanel with other JPanels. When I attempt to do this, I get a completely blank JPanel with dividers.
______________________________________________________________________________
public class Panel extends JPanel implements Runnable, ActionListener {
public Panel(){
JFrame frame = new JFrame();
ctsMenu = new JPanel(new GridLayout(2,2));
ctsMenu.setPreferredSize(new Dimension(500,500));
for (int iRows = 0; iRows < 2 ; iRows++){
for (int iColumns = 0; iColumns < 2; iColumns++){
sGrid[iRows][iColumns] = new JButton ("("+iRows+","+iColumns+")");
ctsMenu.add(sGrid[iRows][iColumns]);
sGrid[iRows][iColumns].addActionListener(this);
panel.add(ctsMenu);
}
}
sGrid[0][0].setText("A");
sGrid[0][1].setText("B");
sGrid[1][0].setText("C");
sGrid[1][1].setText("D");
frame.setContentPane(panel);
frame.pack();
frame.setVisible(true);
}}
____________________________________________________________________
public MainFrame()
{
setTitle( "Split Pane Application" );
setBackground( Color.GREEN );
JPanel topPanel = new JPanel();
topPanel.setLayout( new BorderLayout() );
getContentPane().add( topPanel );
createPanel1();
createPanel2();
createPanel3();
createPanel4();
splitPaneV = new JSplitPane( JSplitPane.VERTICAL_SPLIT );
topPanel.add( splitPaneV, BorderLayout.CENTER );
splitPaneV.setDividerLocation(300);
splitPaneV.setLeftComponent( gamePanel);
// gamePanel.addKeyListener(new KeyListener());
gamePanel.setFocusable(true);
gamePanel.requestFocusInWindow();
splitPaneV.setRightComponent( panel3 );
}
}
public void createPanel1(){
// deleted to take up less space
}
public void createPanel2(){
// deleted to take up less space
}
public void createPanel3(){
panel3 = new Panel();
}
public void createPanel4(){
//deleted to take up less space
}
}
You ask:
Is it possible to add a JPanel with JButtons to a Split JPanel?
Yes, it is most definitely possible to do this. It's something similar to what we do all the time:
import javax.swing.*;
public class SplitPaneEg {
private static void createAndShowGui() {
JPanel panel1 = new JPanel();
panel1.setBorder(BorderFactory.createTitledBorder("Panel 1"));
panel1.add(new JButton("Button 1"));
panel1.add(new JButton("Button 2"));
JPanel panel2 = new JPanel();
panel2.setBorder(BorderFactory.createTitledBorder("Panel 2"));
panel2.add(new JButton("Button 1"));
panel2.add(new JButton("Button 2"));
JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, panel1,
panel2);
JFrame frame = new JFrame("Split Pane Example");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(splitPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
You state:
Right now, I have the JPanel with JButtons added to a JFrame, but I want it on a JPanel with other JPanels. When I attempt to do this, I get a completely blank JPanel with dividers.
Then you have an error in your code, but unfortunately based on code you've posted I doubt that any of us can do more than just guess. If you need more specific help, then you will want to post a small runnable example that demonstrates your problem, an sscce.

Adding buttons below JTextArea

I am trying to add two buttons below the JTextArea using the Eclipse WindowBuilder, but I can't. I tried to change the layout, but I couldn't find a way to add buttons where I want and to re-size the JTextArea in an easy way.
public TestScrollPane03() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JTextArea textArea = new JTextArea(100, 50);
JScrollPane scrollPane = new JScrollPane(textArea);
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(scrollPane);
frame.setSize(200, 200);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
How would I go about adding buttons below my original textArea?
You need to have two panels, one for your textArea, and one for your input (in this case buttons). I think something like this is what you are looking for:
public class Test
{
public static void createFrame()
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setOpaque(true);
JTextArea textArea = new JTextArea(15, 50);
textArea.setWrapStyleWord(true);
textArea.setEditable(false);
textArea.setFont(Font.getFont(Font.SANS_SERIF));
JScrollPane scroller = new JScrollPane(textArea);
scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
JPanel inputpanel = new JPanel();
inputpanel.setLayout(new FlowLayout());
JTextField input = new JTextField(20);
JButton button = new JButton("Enter");
DefaultCaret caret = (DefaultCaret) textArea.getCaret();
caret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE);
panel.add(scroller);
inputpanel.add(input);
inputpanel.add(button);
panel.add(inputpanel);
frame.getContentPane().add(BorderLayout.CENTER, panel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
frame.setResizable(false);
input.requestFocus();
}
});
}
public static void main(String... args)
{
createFrame();
}
}
If you want your frame to look more like those of the OS you are running on, you can add .setLookAndFeel() before you make the frame visible:
try
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace();
}
What adding the UIManager looks like (notably a bit smaller):

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