Develop Reference

GridLayout is misbehaving

I am trying to write Swing by hand (yeah crazy, I know) and for some reason this part panel I create here:
private JPanel createColorSliderPanel() {
JPanel colorSliderPanel = new JPanel(new GridLayout(3, 1, 0, 5));
JPanel redSliderPanel = new JPanel(new BorderLayout());
JPanel greenSliderPanel = new JPanel(new BorderLayout());
JPanel blueSliderPanel = new JPanel(new BorderLayout());
GridLayout grid = (GridLayout) colorSliderPanel.getLayout();
redSlider = new JSlider();
greenSlider = new JSlider();
blueSlider = new JSlider();
redField = new JTextField();
greenField = new JTextField();
blueField = new JTextField();
redField.setEditable(false);
greenField.setEditable(false);
blueField.setEditable(false);
JLabel redLabel = new JLabel("Red");
JLabel greenLabel = new JLabel("Green");
JLabel blueLabel = new JLabel("Blue");
redLabel.setPreferredSize(new Dimension(64, 16));
redField.setPreferredSize(new Dimension(32, 16));
redSliderPanel.add(redLabel, BorderLayout.WEST);
redSliderPanel.add(redSlider, BorderLayout.CENTER);
redSliderPanel.add(redField, BorderLayout.EAST);
greenLabel.setPreferredSize(new Dimension(64, 16));
greenField.setPreferredSize(new Dimension(32, 16));
greenSliderPanel.add(redLabel, BorderLayout.WEST);
greenSliderPanel.add(redSlider, BorderLayout.CENTER);
greenSliderPanel.add(redField, BorderLayout.EAST);
blueLabel.setPreferredSize(new Dimension(64, 16));
blueField.setPreferredSize(new Dimension(32, 16));
blueSliderPanel.add(redLabel, BorderLayout.WEST);
blueSliderPanel.add(redSlider, BorderLayout.CENTER);
blueSliderPanel.add(redField, BorderLayout.EAST);
colorSliderPanel.add(redSliderPanel);
colorSliderPanel.add(greenSliderPanel);
colorSliderPanel.add(blueSliderPanel);
return colorSliderPanel;
}
doesn't work as intended:
It's supposed to stack the three panels I make on top of each other. I add it to my JFrame like this:
JPanel sliderPanel = createColorSliderPanel();
...
contentPane.add(sliderPanel, BorderLayout.SOUTH);
Any clue why it doesn't display properly?

The problem is, you only adding the redSlider/Field/Label to all of the other panels
redSliderPanel.add(redLabel, BorderLayout.WEST);
redSliderPanel.add(redSlider, BorderLayout.CENTER);
redSliderPanel.add(redField, BorderLayout.EAST);
greenSliderPanel.add(redLabel, BorderLayout.WEST);
greenSliderPanel.add(redSlider, BorderLayout.CENTER);
greenSliderPanel.add(redField, BorderLayout.EAST);
blueSliderPanel.add(redLabel, BorderLayout.WEST);
blueSliderPanel.add(redSlider, BorderLayout.CENTER);
blueSliderPanel.add(redField, BorderLayout.EAST);
Doing this, will remove the redSlider, redField and redLabel from the container it was previous added to meaning that it will only appear on the blueSliderPanel.
Don't use setPreferred/Minimum/MaximumSize, you don't control the metrics by which a component measures it's required sizes. Provide sizing hints to the components so that they can make better decisions.
redField = new JTextField(4);
greenField = new JTextField(4);
blueField = new JTextField(4);
Then don't add the fields to sub panels first
Then don't add your fields to separate panels first, but, you might find that something like GridBagLayout makes a better choice...
JPanel colorSliderPanel = new JPanel(new GridBagLayout());
redSlider = new JSlider();
greenSlider = new JSlider();
blueSlider = new JSlider();
redField = new JTextField(4);
greenField = new JTextField(4);
blueField = new JTextField(4);
redField.setEditable(false);
greenField.setEditable(false);
blueField.setEditable(false);
JLabel redLabel = new JLabel("Red");
JLabel greenLabel = new JLabel("Green");
JLabel blueLabel = new JLabel("Blue");
addTo(colorSliderPanel, redLabel, redSlider, redField, 0);
addTo(colorSliderPanel, greenLabel, greenSlider, greenField, 1);
addTo(colorSliderPanel, blueLabel, blueSlider, blueField, 2);
And the addTo method...
protected void addTo(JPanel parent, JLabel label, JSlider slider, JTextField field, int gridY) {
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.WEST;
gbc.gridx = 0;
gbc.gridy = gridY;
parent.add(label, gbc);
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.gridx++;
gbc.weightx = 1;
parent.add(slider, gbc);
gbc.gridx++;
gbc.weightx = 0;
parent.add(field, gbc);
}

Put 4 JLabel at corners of a JFrame

As the title said, I'm trying to put 4 different JLabels at each of the corners of a JFrame. I want them to stay there forever even if I try to resize the JFrame
I've tried using a layout manager but I just can't get it right.
ImageIcon icon;
JLabel labelNW = new JLabel();
JLabel labelNE = new JLabel();
JLabel labelSW = new JLabel();
JLabel labelSE = new JLabel();
URL buttonURL = InputOutputTest.class.getResource("images/square_dot.gif");
if(buttonURL != null){
icon = new ImageIcon(buttonURL);
labelNW.setIcon(icon);
labelNE.setIcon(icon);
labelSW.setIcon(icon);
labelSE.setIcon(icon);
}
window.add(labelNW, BorderLayout.NORTH);
//window.add(labelNE, BorderLayout.EAST);
//window.add(labelSW, BorderLayout.WEST);
window.add(labelSE, BorderLayout.SOUTH);
This code takes care of the north and south of the left side. I'm probably approaching this wrong though.
I also tried GridLayout (2,2) but they weren't at the corners and there's a huge gap on the right side.

You will want to nest JPanels each using its own layout. In fact you could do this by nesting JPanels that all use BorderLayout.
Going to check if GridBagLayout can do it in one shot.... hang on...
Yep GridBagLayout does it too:
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.*;
public class GridBagExample {
public static void main(String[] args) {
JPanel mainPanel = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints(0, 0, 1, 1, 1.0, 1.0,
GridBagConstraints.NORTHWEST, GridBagConstraints.NONE, new Insets(
0, 0, 0, 0), 0, 0);
mainPanel.add(new JLabel("Left Upper"), gbc);
gbc.gridx = 1;
gbc.gridy = 0;
gbc.anchor = GridBagConstraints.NORTHEAST;
mainPanel.add(new JLabel("Right Upper"), gbc);
gbc.gridx = 0;
gbc.gridy = 1;
gbc.anchor = GridBagConstraints.SOUTHWEST;
mainPanel.add(new JLabel("Left Lower"), gbc);
gbc.gridx = 1;
gbc.gridy = 1;
gbc.anchor = GridBagConstraints.SOUTHEAST;
mainPanel.add(new JLabel("Right Lower"), gbc);
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.setLocationRelativeTo(null);
frame.pack();
frame.setVisible(true);
}
}
Edit
Now for the BorderLayout example:
import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.*;
public class BorderLayoutExample {
public static void main(String[] args) {
JPanel northPanel = new JPanel(new BorderLayout());
northPanel.add(new JLabel("North East"), BorderLayout.EAST);
northPanel.add(new JLabel("North West"), BorderLayout.WEST);
JPanel southPanel = new JPanel(new BorderLayout());
southPanel.add(new JLabel("South East"), BorderLayout.EAST);
southPanel.add(new JLabel("South West"), BorderLayout.WEST);
JPanel mainPanel = new JPanel(new BorderLayout());
mainPanel.add(northPanel, BorderLayout.NORTH);
mainPanel.add(southPanel, BorderLayout.SOUTH);
JFrame frame = new JFrame("BorderLayout Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
}

I find that only GroupLayout gives me the control I need for precisely laid out components. This should do the trick. You need to make sure the gap in between has a very large Maximum value (i.e. Short.MAX_VALUE), but you can set the minimum and preferred sizes to whatever you want.
public class LabelFrame extends JFrame {
public LabelFrame() {
JPanel contentPane = new JPanel();
JLabel labelNW = new JLabel();
JLabel labelNE = new JLabel();
JLabel labelSW = new JLabel();
JLabel labelSE = new JLabel();
URL buttonURL = InputOutputTest.class.getResource("images/square_dot.gif");
if(buttonURL != null){
icon = new ImageIcon(buttonURL);
labelNW.setIcon(icon);
labelNE.setIcon(icon);
labelSW.setIcon(icon);
labelSE.setIcon(icon);
}
GroupLayout layout = new GroupLayout(contentPane);
layout.setHorizontalGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(Alignment.LEADING)
.addComponent(labelNW)
.addComponent(labelSW))
.addGap(20,50,Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(Alignment.TRAILING)
.addComponent(labelNE)
.addComponent(labelSE))
);
layout.setVerticalGroup(layout.createSequentialGroup()
.addGroup(layout.createParallelGroup(Alignment.LEADING)
.addComponent(labelNW)
.addComponent(labelNE))
.addGap(20,50,Short.MAX_VALUE)
.addGroup(layout.createParallelGroup(Alignment.TRAILING)
.addComponent(labelSW)
.addComponent(labelSE))
);
contentPane.setLayout(layout);
setContentPane(contentPane);
pack();
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
LabelFrame frame = new LabelFrame();
frame.setVisible(true);
}
});
}
}

I've tried using a layout manager..
Layout managers are wonderful at what they do, but are perhaps the wrong tool for this job. Consider using a custom border instead. Here is an example.

JScrollPane not properly stretching horizontal distance in GridBagLayout

I've seen other posts on this subject, but the solutions they found do not apply to me. I am setting a weighted value and using the c.fill = GridBagConstraints.BOTH constraints as well.
I'm including the whole GUI code I have, just in case my mistake is coming form something other than the GridBagLayout.
I want the scrollable text block on the right to expand the remaining space within the GUI and I have set all the variables that should be attributed to that and yet it still isn't working. What am I doing wrong?
My result:
import java.awt.*;
import javax.swing.*;
public class TestCode extends JFrame {
JTextArea textArea = new JTextArea ();
JComboBox <String> typeComboBox;
JTextField searchField;
JTextField fileField;
public TestCode(){
setTitle ("GUI Test");
setSize (600, 300);
setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
setVisible (true);
JScrollPane scrollPane = new JScrollPane(textArea);
JButton readButton = new JButton("Read File");
JButton displayButton = new JButton("Display");
JButton searchButton = new JButton("Search");
searchField = new JTextField(10);
fileField = new JTextField(15);
typeComboBox = new JComboBox <String> ();
typeComboBox.addItem("Index");
typeComboBox.addItem("Type");
typeComboBox.addItem("Name");
JPanel container = new JPanel();
container.setLayout(new GridBagLayout());
container.setPreferredSize(new Dimension(250, 100));
JPanel filePanel = new JPanel();
filePanel.setLayout(new BoxLayout(filePanel, BoxLayout.Y_AXIS));
filePanel.add(new JLabel("Source file", SwingConstants.LEFT));
JPanel filePanelTop = new JPanel();
filePanelTop.setLayout(new FlowLayout(FlowLayout.LEFT));
filePanelTop.add(fileField);
JPanel filePanelBottom = new JPanel();
filePanelBottom.setLayout(new FlowLayout(FlowLayout.RIGHT));
filePanelBottom.add(readButton);
filePanelBottom.add(displayButton);
filePanel.add(filePanelTop);
filePanel.add(filePanelBottom);
filePanel.setMaximumSize(filePanel.getPreferredSize());
filePanel.setBorder(BorderFactory.createTitledBorder("Import File"));
JPanel searchPanel = new JPanel();
searchPanel.setLayout(new BoxLayout(searchPanel, BoxLayout.Y_AXIS));
searchPanel.add(new JLabel("Search target", SwingConstants.LEFT));
JPanel searchPanelTop = new JPanel();
searchPanelTop.setLayout(new FlowLayout(FlowLayout.LEFT));
searchPanelTop.add(searchField);
searchPanelTop.add(typeComboBox);
searchPanel.add(searchPanelTop);
searchPanel.add(searchButton);
searchPanel.setMaximumSize(searchPanel.getPreferredSize());
searchPanel.setBorder(BorderFactory.createTitledBorder("Search Objects"));
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.gridy = 0;
container.add(filePanel, c);
c.gridx = 0;
c.gridy = 1;
container.add(searchPanel, c);
c.gridx = 1;
c.gridy = 0;
c.weightx = 1.0;
c.weighty = 1.0;
c.gridwidth = GridBagConstraints.REMAINDER;
c.gridheight = GridBagConstraints.REMAINDER;
c.fill = GridBagConstraints.BOTH;
c.anchor = GridBagConstraints.NORTHWEST;
container.add(scrollPane, c);
add(container, BorderLayout.WEST);
validate();
} // end method toString
public static void main(String[] args){
TestCode run = new TestCode();
}
} // end class Treasure

//add(container, BorderLayout.WEST);
add(container);
The West contrains the components to their preferred width. The default is the CENTER which allows components to expand to fill the space available.
Also, the main structure of you code is wrong. You should be adding all the component to the frame first and then invoke:
frame.pack();
frame.setVisible(true);
Then there is no need for the validate().

Positioning components in Swing GUIs

I have some questions on positioning components and some questions on text fields and text areas (Java Swing). Any help is greatly appreciated.
Right now I am trying to have two text fields beside each other with a different label above each describing what that text field does. To achieve this I have placed them in a GridLayout(2, 2).
Is this the best way? It is the only way I know to have a label directly over another component. Is there a better way? What about if there is just one label above one button. Is it sensible to position this through a GridLayout(2, 1)? I am visually impaired so I do not think positioning buttons just by their pixel position is an option unless there is a simple way to place components at a relative number of pixels to another component.
That leads me to my next question.
What is the best way to have the same UI as above but with another component (button) centered under it. Essentially the UI should compose of two Named text fields with a calculate button under. The way I did this is by putting the above components in a panel, and adding that plus the calculate button to a surrounding panel with a GridLayout(2, 1). The problem is that the button becomes as big as the panel above it (I'm assuming). How can I adjust this and still have the button perfectly aligned under the panel of text fields/labels? Similarly with labels above text areas. The label should be small but have a larger space for the text area under.
(text field):
Again referring to the UI above, if the user types many characters into the first text field, will the letters go over the text field on the right? If so how can I prevent this?
If I append text to a text area and it is already full, will it automatically allow the user to scroll? If not what is a simple way to make the text area scrollable?
Right now I am not setting a size of the text area. Does it just grow as I add text? Does it have a default size as in number of characters?

There are a number of layout managers that might be capable of providing you with what you need.
MigLayout
JGoodies FormLayout
GridBagLayout
For, GridBagLayout would be my choice (I'm biased, as I've been using this layout manager for the past 12 years ;))
public class TestLayout17 {
public static void main(String[] args) {
new TestLayout17();
}
public TestLayout17() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
public TestPane() {
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.insets = new Insets(2, 2, 2, 2);
add(new JLabel("Label 1"), gbc);
gbc.gridx++;
add(new JLabel("Label 2"), gbc);
gbc.gridx = 0;
gbc.gridy++;
gbc.fill = GridBagConstraints.HORIZONTAL;
add(new JTextField(10), gbc);
gbc.gridx++;
add(new JTextField(10), gbc);
gbc.gridx = 0;
gbc.gridy++;
gbc.fill = GridBagConstraints.NONE;
gbc.gridwidth = 2;
add(new JButton("Click"), gbc);
}
}
}
I also agree with Eng.Fouad's suggestion of using compound containers to make your life easier in the long run
You might find Laying Out Components Within a Container a worth while read.

Right now I am trying to have two text fields beside each other with a
different label above each describing what that textfield does. To
achieve this I have placed them in a GridLayout(2, 2). Is this the
best way? It is the only way I know to have a label directly over
another component. Is there a better way? What about if there is just
one label above one button. Is it sensible to position this through a
GridLayout(2, 1)?
Myself, I always do it via nested panels with BorderLayout. For example:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
panOuter.add(panLeft, BorderLayout.WEST);
panOuter.add(panRight, BorderLayout.EAST);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
Note that, you can manipulate the gaps between the components with setting empty borders. Also, you may use BorderLayout.LINE_START and BorderLayout.LINE_END instead of using BorderLayout.WEST and BorderLayout.EAST, and this will add support for RTL languages (e.g Arabic).
That leads me to my next question. What is the best way to have the
same UI as above but with another component (button) centred under it.
Essentially the UI should compose of two Named text fields with a
calculate button under. The way I did this is by putting the above
components in a panel, and adding that plus the calculate button to a
surrounding panel with a GridLayout(2, 1). The problem is that the
button becomes as big as the panel above it (I'm assuming). How can I
adjust this and still have the button perfectly aligned under the
panel of textfields/labels?
I would do it via nested panels as I did earlier, but now the bottom panel has a FlowLayout layout manager to get a good size for the button:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panBottom = new JPanel(); // default is FlowLayout
panBottom.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
panOuter.add(panLeft, BorderLayout.WEST);
panOuter.add(panRight, BorderLayout.EAST);
panOuter.add(panBottom, BorderLayout.SOUTH);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
JButton btnBottom = new JButton("Press it!");
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
panBottom.add(btnBottom);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
Similarly with labels above text areas. The label should be small but
have a larger space for the text area under.
I would suggest you to use TitledBorder:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panBottom = new JPanel(); // default is FlowLayout
panBottom.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panInput = new JPanel(new BorderLayout());
panInput.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panConsole = new JPanel(new BorderLayout());
Border outsideBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border insideBorder = BorderFactory.createTitledBorder("The Console");
Border theBorder = BorderFactory.createCompoundBorder(outsideBorder, insideBorder);
panConsole.setBorder(theBorder);
panInput.add(panLeft, BorderLayout.WEST);
panInput.add(panRight, BorderLayout.EAST);
panInput.add(panBottom, BorderLayout.SOUTH);
panOuter.add(panInput, BorderLayout.NORTH);
panOuter.add(panConsole, BorderLayout.CENTER);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
JButton btnBottom = new JButton("Press it!");
JTextArea txtConsole = new JTextArea(5, 10);
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
panBottom.add(btnBottom);
panConsole.add(txtConsole, BorderLayout.CENTER);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
third (text field): Again referring to the UI above, if the user types
many characters into the first text field, will the letters go over
the text field on the right? If so how can I prevent this?
Try the above code, and see how it acts :)
Fourth: If I append text to a text area and it is already full, will
it automatically allow the user to scroll? If not what is a simple way
to make the text area scrollable?
You need to use something called JScrollPane:
JFrame frame = new JFrame("The Title");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panOuter = new JPanel(new BorderLayout());
JPanel panLeft = new JPanel(new BorderLayout());
panLeft.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panRight = new JPanel(new BorderLayout());
panRight.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panBottom = new JPanel(); // default is FlowLayout
panBottom.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panInput = new JPanel(new BorderLayout());
panInput.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
JPanel panConsole = new JPanel(new BorderLayout());
Border outsideBorder = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border insideBorder = BorderFactory.createTitledBorder("The Console");
Border theBorder = BorderFactory.createCompoundBorder(outsideBorder, insideBorder);
panConsole.setBorder(theBorder);
panInput.add(panLeft, BorderLayout.WEST);
panInput.add(panRight, BorderLayout.EAST);
panInput.add(panBottom, BorderLayout.SOUTH);
panOuter.add(panInput, BorderLayout.NORTH);
panOuter.add(panConsole, BorderLayout.CENTER);
JLabel lblLeft = new JLabel("Label 1", JLabel.CENTER);
JLabel lblRight = new JLabel("Label 2", JLabel.CENTER);
JTextField txtLeft = new JTextField(10);
JTextField txtLright = new JTextField(10);
JButton btnBottom = new JButton("Press it!");
JTextArea txtConsole = new JTextArea(5, 10);
JScrollPane srcPane = new JScrollPane(txtConsole,
JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
panLeft.add(lblLeft, BorderLayout.NORTH);
panLeft.add(txtLeft, BorderLayout.CENTER);
panRight.add(lblRight, BorderLayout.NORTH);
panRight.add(txtLright, BorderLayout.CENTER);
panBottom.add(btnBottom);
panConsole.add(srcPane, BorderLayout.CENTER);
frame.setContentPane(panOuter);
frame.pack();
frame.setVisible(true);
I hope I answered all of your questions :)

Adding JPanel to JScrollPane

I have a gui which has a Panel that contains a sequence of labels and TextFields and uses a spring layout(this is the mainPanel) and another Panel that just contains a button(buttonPanel). I am trying to make my mainPanel to have a vertical scrollbar as well. I would like to implement my GUI such that within the JFrame I have 2 panels. The mainPanel appears on the top of the frame and the buttonPanel appears below the mainPanel.
My problem is I am not able to make the Panels appear such that the buttonPanel is below the mainPanel and I am also not sure how to add a scrollbar to the mainPanel. Any help would be appreciated.
EDIT : I was able to solve my issue regarding the JPanels, now my only problem is that I cant get my mainPanel to scroll. I've added my most recent code below :
Here is the code I have so far:
public static void main(String args[]) {
JFrame frame = new JFrame("SpringLayout");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scroll = new JScrollPane();
Container contentPane = frame.getContentPane();
JButton next = new JButton("Next");
JPanel buttonPanel = new JPanel();
buttonPanel.add(next);
SpringLayout layout = new SpringLayout();
JPanel mainPanel = new JPanel();
mainPanel.setLayout(layout);
contentPane.setLayout(new BorderLayout());
int j = 25;
for(int i =0;i<150;i++){
JLabel label = new JLabel("Enter Name " + i );
JTextField text = new JTextField(15);
mainPanel.add(label);
mainPanel.add(text);
layout.putConstraint(SpringLayout.WEST, label, 10, SpringLayout.WEST,
contentPane);
layout.putConstraint(SpringLayout.NORTH, label, j, SpringLayout.NORTH,
contentPane);
layout.putConstraint(SpringLayout.NORTH, text, j, SpringLayout.NORTH,
contentPane);
layout.putConstraint(SpringLayout.WEST, text, 20, SpringLayout.EAST,
label);
j+=30;
}
//mainPanel.setSize(500,800);
scroll.setPreferredSize(new Dimension(500,500));
scroll.setViewportView(mainPanel);
contentPane.add(scroll);
contentPane.add(buttonPanel,BorderLayout.SOUTH);
//mainWindow.add(contentPane);
frame.setSize(500, 600);
frame.setVisible(true);
}

To make it scrollable I just needed to increase the preferred size of my mainPanel such that it would be bigger than the scrollbar.
public static void main(String args[]) {
JFrame frame = new JFrame("SpringLayout");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JScrollPane scroll = new JScrollPane();
Container contentPane = frame.getContentPane();
JButton next = new JButton("Next");
JPanel buttonPanel = new JPanel();
buttonPanel.add(next);
SpringLayout layout = new SpringLayout();
JPanel mainPanel = new JPanel();
mainPanel.setLayout(layout);
contentPane.setLayout(new BorderLayout());
int j = 25;
for(int i =0;i<18;i++){
JLabel label = new JLabel("Enter Name " + i );
JTextField text = new JTextField(15);
mainPanel.add(label);
mainPanel.add(text);
layout.putConstraint(SpringLayout.WEST, label, 10, SpringLayout.WEST,
contentPane);
layout.putConstraint(SpringLayout.NORTH, label, j, SpringLayout.NORTH,
contentPane);
layout.putConstraint(SpringLayout.NORTH, text, j, SpringLayout.NORTH,
contentPane);
layout.putConstraint(SpringLayout.WEST, text, 20, SpringLayout.EAST,
label);
j+=30;
}
mainPanel.setPreferredSize(new Dimension(mainPanel.getWidth(), 1500));
scroll.setPreferredSize(new Dimension(500,500));
scroll.setViewportView(mainPanel);
contentPane.add(scroll);
contentPane.add(buttonPanel,BorderLayout.SOUTH);
//mainWindow.add(contentPane);
frame.setSize(500, 600);
frame.setVisible(true);
}

I can't comment something, to try and compare
notice in this moment I don't understand why SpringLayout and JFrame#pack() doesn't build proper GUI based on PreferredSize, bump in this looks like as (in this moment) my issue too
code with hardcoded JFrame.setSize() instead of proper JFrame#pack()
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.SpringLayout;
import javax.swing.SwingUtilities;
public class Main {
public Main() {
JFrame frame = new JFrame("SpringLayout");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton next = new JButton("Next");
JPanel buttonPanel = new JPanel();
buttonPanel.add(next);
SpringLayout layout = new SpringLayout();
JPanel mainPanel = new JPanel();
mainPanel.setLayout(layout);
int j = 25;
for (int i = 0; i < 5; i++) {
JLabel label = new JLabel("Enter Name");
JTextField text = new JTextField(15);
layout.putConstraint(SpringLayout.WEST, label, 10, SpringLayout.WEST,
mainPanel);
layout.putConstraint(SpringLayout.NORTH, label, j, SpringLayout.NORTH,
mainPanel);
layout.putConstraint(SpringLayout.NORTH, text, j, SpringLayout.NORTH,
mainPanel);
layout.putConstraint(SpringLayout.WEST, text, 20, SpringLayout.EAST,
label);
j += 30;
mainPanel.add(label);
mainPanel.add(text);
}
frame.add(mainPanel, BorderLayout.CENTER);
frame.add(buttonPanel, BorderLayout.SOUTH);
frame.setSize(300, 300);
frame.setVisible(true);
}
public static void main(String args[]) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
Main mn = new Main();
}
});
}
}

This is how I would do it:
public static void main(String args[]) {
JFrame frame = new JFrame("SpringLayout");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Container contentPane = frame.getContentPane();
JButton next = new JButton("Next");
JPanel buttonPanel = new JPanel();
buttonPanel.add(next);
GridBagLayout layout = new GridBagLayout();
JPanel mainPanel = new JPanel();
mainPanel.setLayout(layout);
contentPane.setLayout(new BorderLayout());
GridBagConstraints gbc = new GridBagConstraints();
int j = 25;
for (int i = 0; i < 50; i++) {
JLabel label = new JLabel("Enter Name (" + i + ")");
JTextField text = new JTextField(15);
gbc.gridx = 0;
gbc.gridy = i;
mainPanel.add(label, gbc);
gbc.gridx = 1;
mainPanel.add(text, gbc);
}
contentPane.add(new JScrollPane(mainPanel, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED), BorderLayout.CENTER);
contentPane.add(buttonPanel, BorderLayout.SOUTH);
frame.setSize(500, 800);
frame.setVisible(true);
}
Few modifications:
* use GridBagLayout instead of SpringLayout (just because I don't know SpringLayout)
* wrap your mainPanel inside a JScrollPane
Does not look and feel exactly like your example. GridBagConstraints can be tuned.