The code below places 3 JPanels inside a JFrame. I want the blue colored panel to have a width of 300 (assume the enclosing Frame has a width of greater than 300). The width of the other two panels should be the remainder. How do I do that?
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Frame;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class PanelTest extends JFrame {
private JPanel leftpanel;
public PanelTest() {
getContentPane().setLayout(new BoxLayout(this.getContentPane(), BoxLayout.X_AXIS));
this.leftpanel = new JPanel() {
#Override
public Dimension getMaximumSize() {
return new Dimension(300, 9999);
}
#Override
public Dimension getMinimumSize() {
return new Dimension(300, 0);
}
};
this.leftpanel.setBackground(Color.blue);
getContentPane().add(leftpanel);
JPanel rightpanel = new JPanel();
getContentPane().add(rightpanel);
rightpanel.setLayout(new BoxLayout(rightpanel, BoxLayout.Y_AXIS));
JPanel upperpanel = new JPanel();
upperpanel.setBackground(Color.red);
rightpanel.add(upperpanel);
JPanel lowerpanel = new JPanel();
lowerpanel.setBackground(Color.yellow);
rightpanel.add(lowerpanel);
pack();
setVisible(true);
setExtendedState(Frame.MAXIMIZED_BOTH);
}
public static void main(String[] args) {
new PanelTest();
}
}
I slightly updated the above code using #camickr's suggestion of using BorderLayout. The width is now as desired. Thanks #camickr.
I still think BoxLayout should have respected the minimum and maximum sizes. Taking those into consideration, it should have set the width to 500.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Frame;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class PanelTest extends JFrame {
public PanelTest() {
getContentPane().setLayout(new BorderLayout());
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel leftpanel = new JPanel();
int width = 500;
leftpanel.setPreferredSize(new Dimension(width, 1));
leftpanel.setBackground(Color.blue);
getContentPane().add(leftpanel, BorderLayout.LINE_START);
JPanel rightpanel = new JPanel();
getContentPane().add(rightpanel, BorderLayout.CENTER);
rightpanel.setLayout(new BoxLayout(rightpanel, BoxLayout.Y_AXIS));
JPanel upperpanel = new JPanel();
upperpanel.setBackground(Color.red);
rightpanel.add(upperpanel);
JPanel lowerpanel = new JPanel();
lowerpanel.setBackground(Color.yellow);
rightpanel.add(lowerpanel);
pack();
setVisible(true);
setExtendedState(Frame.MAXIMIZED_BOTH);
}
public static void main(String[] args) {
new PanelTest();
}
}
The most important size of a component is the preferred size. Most layout managers will use this size first and then maybe use the minimum/maximum sizes depending on the space available.
If you don't specify a preferred size of the panel it will be (10, 10) since this is the default size of a panel using the FlowLayout when no components are added.
This size is outside the bounds of your minimum/maximum values so it appears the BoxLayout will then allocate space to each component in a ratio based on the maximum size of each panel. The blue panel has a size of 300 and the other panel has a size of Integer.MAX_VALUE so much more space gets allocated to the other panel.
One solution is to add:
leftpanel.setPreferredSize(new Dimension(300, 1));
I want the blue colored panel to have a width of 300
I would not change the content pane to use a BoxLayout and instead just use the default BorderLayout of the frame. Then you:
add the blue panel to the BorderLayout.LINE_START.
Add the panel containing the red/yellow components to the BorderLayout.CENTER.
The BorderLayout will respect the width of the blue panel and give the remaining space to the component in the center.
Using this approach there is no need to override the minimum/maximum values of the blue panel.
Of course you would still need to set the preferred size of the blue panel.
Related
This question is very similiar to this: JScrollPane doesn't top align when there is more than enough space to show the content I tried this solution, but it does not work.
When I add a jlabel to jscrollpane, when the jlabel is small, the label becomes centered. It works normally when the scrollbar shows. Setting boxlayout does not change anything. I feel like this isn't working properly because I'm setting a perferred size to the panel? But if I remove the line panel.setPreferredSize(new Dimension((int)(screenSize.width*0.7 - 50), screenSize.height-150)); The label becomes small when there is no text, and grows to accomdate text, which I don't want. If I add the panel instead of the label, it makes the screen scrollable even though there isn't text?
This is my code:
public class Test {
// JFrame
static JFrame frame = new JFrame("Test");
//panel 1
static JPanel panel = new JPanel(new BorderLayout());
// label to display text
static JLabel label = new JLabel();
//scroll panel in main method
public static void main(String[] args) throws Exception {
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
label.setBorder(new EmptyBorder(5, 5, 5, 20));
label.setText("any text makes it centered beyond 40 lines");
//create panel
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.add(label, BorderLayout.NORTH);
panel.add(Box.createVerticalGlue());
panel.setPreferredSize(new Dimension((int)(screenSize.width*0.7 - 50), screenSize.height-150));
panel.setBorder(new EmptyBorder(5, 5, 5, 10));
JScrollPane jspanel = new JScrollPane(label, ScrollPaneConstants.VERTICAL_SCROLLBAR_AS_NEEDED, ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
//jspanel.add(label, BorderLayout.CENTER);
jspanel.setPreferredSize(new Dimension((int)(screenSize.width*0.7 - 70), screenSize.height-180));
jspanel.getVerticalScrollBar().setUnitIncrement(20);
jspanel.setBorder(BorderFactory.createEmptyBorder());
jspanel.setAlignmentX(JScrollPane.LEFT_ALIGNMENT);
jspanel.setAlignmentY(JScrollPane.TOP_ALIGNMENT);
//panel.setPreferredSize(new Dimension(640, 480));
//frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(jspanel);
frame.setSize((int)(screenSize.width*0.7), screenSize.height - 50);
frame.revalidate();
frame.pack();
frame.setVisible(true);
}
}
jspanel.setAlignmentX(JScrollPane.LEFT_ALIGNMENT);
jspanel.setAlignmentY(JScrollPane.TOP_ALIGNMENT);
That will align the scrollpane in its parent container, depending on the layout manager being used. It does not affect the alignment of any component added to the scrollpane. It is not needed.
the label becomes centered
The label is sized to fill the entire space available, so you need to customize how the text of the label is painted.
If you don't want it centered then you can place it at the top using:
label.setVerticalAlignment( SwingConstants.TOP );
After reworking your code, I came up with the following GUI.
I added a call to the SwingUtilities invokeLater method. This method ensures that all Swing components are created and executed on the Event Dispatch Thread.
I eliminated all static references, except for the main method.
I reworked your code into methods so I could focus on one part of the GUI at a time.
Here's the complete runnable example. This is a minimal reproducible example.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;
import javax.swing.border.EmptyBorder;
public class JScrollPaneTestGUI implements Runnable {
public static void main(String[] args) {
SwingUtilities.invokeLater(new JScrollPaneTestGUI());
}
#Override
public void run() {
JFrame frame = new JFrame("JScrollPane Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane jspanel = createJScrollPane();
frame.add(jspanel, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
}
private JScrollPane createJScrollPane() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBackground(Color.YELLOW);
panel.setPreferredSize(new Dimension(400, 300));
JLabel label = new JLabel();
label.setBorder(new EmptyBorder(5, 5, 5, 20));
label.setText("any text makes it centered beyond 40 lines");
//create panel
panel.add(label, BorderLayout.NORTH);
JScrollPane jspanel = new JScrollPane(panel);
return jspanel;
}
}
I have a JPanel with Box.createVerticalBox() layout containing five JPanels. (1) Labels, (2) a table (3) a JTextField (4) a JTextArea (5) buttons.On resize:
labels should stick to top left corner and keep the same size,
JTextField should stick to left size between (2) and (4) and expand to full width of the frame
Buttons should stick to bottom right corner and keep the same size,
JTable and JTextArea should expand to full width of the frame and equally divide remaining space
I've tried several layouts, but couldn't make resizing work.
To run this program two classes are required EditPanel.java :
import java.awt.BorderLayout;
import java.awt.FlowLayout;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class EditPanel extends JPanel {
private JPanel p1Labels;
private JPanel p2Table;
private JPanel p3ecnTitle;
private JPanel p5Buttons;
private JTextField fieldK;
private JTextField fieldS;
private JScrollPane myScrollBar;
private Box theBox;
public EditPanel() {
init();
}
public void init() { // Creating a vertical Box layout with five sections, placing jpanels there
//First panel with buttons
p1Labels = new JPanel(new FlowLayout(FlowLayout.LEFT, 2, 2));
fieldK = new JTextField("Animal");
fieldS = new JTextField("Fox");
p1Labels.add(new JLabel("Kindom: "));
p1Labels.add(fieldK);
p1Labels.add(new JLabel("Species: "));
p1Labels.add(fieldS);
//Second panel with a table
p2Table = new JPanel(new FlowLayout(FlowLayout.LEFT, 2, 2));
String[] columnNames = {"First", "Second", "Third", "Fourth"};
Object[][] data = {{"11", "12", "13", "Forteen"},{"21", "22", "23", "Twenty four"}};
JTable table = new JTable(data, columnNames);
JScrollPane scrollPane1 = new JScrollPane(new JTable(data, columnNames));
table.setFillsViewportHeight(true);
p2Table.add(scrollPane1, BorderLayout.CENTER);
//Third panel with a JTextField
p3ecnTitle = new JPanel(new FlowLayout(FlowLayout.LEFT, 2, 2));
p3ecnTitle.add(new JLabel("Title: "));
p3ecnTitle.add(new JTextField("", 14));
//Forth panel with JTextArea
//p4TextArea = new JPanel(new FlowLayout(FlowLayout.LEFT, 2, 2));//tried this too
JTextArea ecnArea = new JTextArea(10, 20);
ecnArea.setText("");
ecnArea.setName("Note");
ecnArea.setLineWrap(true);
ecnArea.setWrapStyleWord(true);
myScrollBar = new JScrollPane(ecnArea,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
//Fifth container with buttons
p5Buttons = new JPanel(new FlowLayout(FlowLayout.RIGHT, 2, 2));
p5Buttons.add(new JButton("SAVE"));
p5Buttons.add(new JButton("DELETE"));
p5Buttons.add(new JButton("CANCEL"));
//Placing everything in a container
theBox = Box.createVerticalBox();
theBox.add(p1Labels);
theBox.add(p2Table);
theBox.add(p3ecnTitle);
//theBox.add(p4TextArea);
theBox.add(myScrollBar);
theBox.add(Box.createVerticalGlue());
theBox.add(p5Buttons);
this.add(theBox);
}
}
And the main.java
import javax.swing.JFrame;
public class Main {
public static void main(String[] args) {
JFrame myFrame;
myPanel EditECNDialog;
myFrame = new JFrame();
EditECNDialog = new myPanel();
myFrame.setTitle("Notes");
myFrame.add(EditECNDialog);
myFrame.pack();
myFrame.setLocationRelativeTo(null);
myFrame.setVisible(true);
}
}
Which Layout handles resizing the best? Can boxlayout handle resizing?
GridBagLayout is the best layout manager for your app. See https://docs.oracle.com/javase/tutorial/uiswing/layout/gridbag.html
You can use a GridBagLayout as Wabbi has already suggested. However is does have the limitation I noted in the comments.
However, if you truly want the textarea and table to always be the same size then you can use the Relative Layout. This layout will first allocate space to components with a fixed size. Then any space remaining is allocated to the components with a relative constraint.
So the basic code would be:
RelativeLayout rl = new RelativeLayout(RelativeLayout.Y_AXIS);
rl.setFill( true );
JPanel panel = new JPanel( rl );
panel.add(labelPanel);
panel.add(tableScrollPane, new Float(1));
panel.add(textField);
panel.add(textAreaScrollPane, new Float(1));
panel.add(buttonsPanel);
Now the table and text area will grow/shrink equally as the frame is resized.
Can boxlayout handle resizing?
Yes it can handle this type of resizing. Box layout respects the maximum size of a component. So if you override the getMaximumSize() method of your panels to return getPreferredSize(), then the panels will not grow in height.
So extra space will be given to the scrollpanes of the text area and table. Again, same concern. Each component will originally be allocated space based on its preferred size.
You should use one variable for gridbagconstraints. This way you can do c.gridy++; c.gridx=0; and c.gridx++;
It will be easier to insert new components later.
Explicit d.gridy=4; makes inserting new components difficult.
I am creating a GUI with a graphics panel, a command panel and a Command List panel. I've got the command panel where I want it at the bottom of the frame using BorderLayout South but my side panel is just tiny and unreadable.
Ill provide a picture of what I want my frame to look like at the end:
What I currently have:
Could anyone explain why the TitledBorder panel is so small?
My code is below:
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
public class PenDriver {
public static void main(String[] args) {
JFrame frame = new JFrame("Pen Simulator");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(600, 400);
penPanel panel = new penPanel();
frame.add(panel);
frame.setVisible(true);
}
}
AND
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import javax.swing.JPanel;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.BoxLayout;
public class penPanel extends JPanel {
private JTextField userCommand;
private JLabel instruction1;
private JButton instruct, clear;
private JLabel cmd1;
public penPanel() {
setLayout(new BorderLayout());
// CREATE THE COMMAND PANEL///////
// Set Layout
JPanel command = new JPanel();
command.setLayout(new BoxLayout(command, BoxLayout.LINE_AXIS));
// Create Label and add to panel
instruction1 = new JLabel("Enter Command:");
// Create Buttons
instruct = new JButton("Execute");
clear = new JButton("Clear Graphics");
// Create Text Field to panel
userCommand = new JTextField(10);
command.add(instruction1);
command.add(Box.createRigidArea(new Dimension(4, 0)));
command.add(userCommand);
command.add(Box.createRigidArea(new Dimension(2, 0)));
command.add(instruct);
command.add(Box.createRigidArea(new Dimension(2, 0)));
command.add(clear);
// COMMAND PANEL FINISHED////////
// CREATE THE COMMAND LIST PANEL//////////
JPanel cmdList = new JPanel();
cmdList.setBorder(BorderFactory.createTitledBorder("Command List:"));
cmdList.setLayout(new BoxLayout(cmdList, BoxLayout.PAGE_AXIS));
cmd1 = new JLabel("UP = up");
cmdList.setSize(new Dimension(50, 400));
cmdList.add(cmd1);
add(command, BorderLayout.SOUTH);
add(cmdList, BorderLayout.EAST);
}
}
Thank you!
EDIT: After some tinkering to this code:
cmdList.setPreferredSize(new Dimension(120, 800));
cmdList.add(cmd1);
add(command, BorderLayout.SOUTH);
command.add(Box.createRigidArea(new Dimension(120, 0)));
add(cmdList, BorderLayout.EAST);
Still not quite what im going for and not sure if it's what I am supposed to do. Should I be altering the driver file rather than the JPanels directly?
Notice how there is still a gap to the right of the "Clear Graphics" Button. Any way to get rid of that?
Could anyone explain why the TitledBorder panel is so small?
The size of the text in the border is not used to determine the size of the component. So the width is determined by the preferred size of the component you add to the panel.
So you need to override the getPreferredSize() method of the panel to return the maximum of the default preferred size calculation or the size of the titled border:
JPanel cmdList = new JPanel()
{
#Override
public Dimension getPreferredSize()
{
Dimension preferredSize = super.getPreferredSize();
Border border = getBorder();
int borderWidth = 0;
if (border instanceof TitledBorder)
{
Insets insets = getInsets();
TitledBorder titledBorder = (TitledBorder)border;
borderWidth = titledBorder.getMinimumSize(this).width + insets.left + insets.right;
}
int preferredWidth = Math.max(preferredSize.width, borderWidth);
return new Dimension(preferredWidth, preferredSize.height);
}
};
Notice how there is still a gap to the right of the "Clear Graphics" Button. Any way to get rid of that?
command.add(Box.createRigidArea(new Dimension(120, 0)));
You just added the rigid area to the command panel so you asked to have the extra 120 pixels at the end.
I have searched the web for a solution to this problem and didn't find anything that worked.
I have a vertical JSlider inside a JPanel that uses GridBagLayout and a GridBagConstraints for positioning the objects on the panel.
Currently I have the following code:
gbc.gridy = 1;
add(button1,gbc);
gbc.gridy = 2;
add(button2,gbc);
gbc.gridy = 3;
add(slider,gbc);
The objects are positioned vertically along the panel.
The slider always appears in the same size (length). Tried to use setPreferredSize - didn't work. Tried to use gridheight in order to have to slider cross two rows - didn't work either. Tried to change the actual min and max values of the slider, didn't help.
Shouldn't GridBagLayout respect preferred size?
EDIT: Also tried creating anoter JPanel inside the main JPanel, set it's layout to FlowLayout, BoxLayout or GridLayout, and add the slider to it. Didn't change a thing. Very weird.
Any ideas?
Use a different layout manager (or put the slider in a nested JPanel with a different layout manager), that will stretch the JSlider. In the example I use BorderLayout
import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.SwingUtilities;
public class DifferentSizeSlider extends JPanel{
public DifferentSizeSlider() {
JPanel topPanel = new JPanel(new BorderLayout());
topPanel.add(new JSlider());
JPanel bottomPanel = new JPanel(new GridLayout(1, 2));
bottomPanel.add(new JSlider());
bottomPanel.add(new JPanel());
setLayout(new GridLayout(2, 1));
add(topPanel);
add(bottomPanel);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
JOptionPane.showMessageDialog(null, new DifferentSizeSlider());
}
});
}
}
EDIT with your code example
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.JButton;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.SwingUtilities;
public class DifferentSizeSlider extends JPanel{
public DifferentSizeSlider() {
JPanel topPanel = new JPanel(new BorderLayout());
topPanel.setPreferredSize(new Dimension(400, 50));
topPanel.add(new JSlider());
JButton jbtOne = new JButton("Button");
JButton jbtTwo = new JButton("Button");
GridBagConstraints gbc = new GridBagConstraints();
setLayout(new GridBagLayout());
gbc.gridy = 0;
add(jbtOne,gbc);
gbc.gridy = 1;
add(jbtTwo,gbc);
gbc.gridy = 2;
add(topPanel, gbc);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable(){
public void run() {
JOptionPane.showMessageDialog(null, new DifferentSizeSlider());
}
});
}
}
To change the size of a swing component you use the setPrefferedSize() method
setPreferredSize(new Dimension(300, 80));
You may have to use a separate panel with a flowLayout for the slider then add that panel to the . Some layout managers may not take the preferred size.
I want to have a resizable panel, that always has the top green panel of a fixed depth. i.e. all changes in height should effect the yellow panel only.
My code below is almost OK, except the green panel varies in size a little.
How do I do this?
Panel.setLayout(new BoxLayout(Panel, BoxLayout.Y_AXIS));
Panel.setAlignmentX(Component.LEFT_ALIGNMENT);
JPanel TopPanel = new JPanel();
TopPanel.setPreferredSize(new Dimension(80,150));
TopPanel.setVisible(true);
TopPanel.setBackground(Color.GREEN);
JPanel MainPanel = new JPanel();
MainPanel.setPreferredSize(new Dimension(80,750));
MainPanel.setVisible(true);
MainPanel.setOpaque(true);
MainPanel.setBackground(Color.YELLOW);
Panel.add(TopPanel);
Panel.add(MainPanel);
Your question didn't restrict the solution to a BoxLayout, so I am going to suggest a different layout manager.
I would attack this with a BorderLayout and put the green panel in the PAGE_START location. Then put the yellow panel in the CENTER location without a preferredSize call.
http://docs.oracle.com/javase/tutorial/uiswing/layout/border.html
Here is an SSCCE example of the solution:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TestPad extends JFrame {
public static void main(String[] args) {
JFrame frame = new JFrame();
frame.getContentPane().setLayout(new BorderLayout());
JPanel green = new JPanel();
green.setPreferredSize(new Dimension(80, 150));
green.setBackground(Color.GREEN);
JPanel yellow = new JPanel();
yellow.setBackground(Color.YELLOW);
frame.getContentPane().add(green, BorderLayout.PAGE_START);
frame.getContentPane().add(yellow, BorderLayout.CENTER);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}
If you make your Panel use BorderLayout instead of BoxLayout and put TopPanel in BorderLayout.NORTH and MainPanel in BorderLayout.CENTER, then they will both resize horizontally, but only the MainPanel will resize vertically.
See the BorderLayout documentation