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How to make JTextField as wide as the window

I want to make the text automatically as wide as the window. I tried using text.setSize(window.getWidth(),20) and text.setBounds(window.getWidth(),20), (where text is JTextfield), but the only way that seems to work is: static JTextField text = new JTextField(int numberOfColumns); I'm using GridBag layout.

EDIT: I have edited example according to GridBagLayout.
Use layout manager. It will automatically expands component according to window.
For example;
Jpanel panel = new JPanel(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.fill = GridBagConstraints.HORIZONTAL;
c.gridwidth = GridBagConstraints.REMAINDER;
panel.add(textfield,c);

JScrollPane and GridBagLayout

I want to create two non-editable textboxes (each will contain only one line) with a fixed size, but I want them to be scrollable (horizontally only) because I know the text they will contain will be very long. I want them to be below the two buttons I define below, and I want each textbox on their own row.
Problem is, everything shows up and buttons work as expected, but the textbox won't scroll, although I can somehow drag and select the rest of the text in the box that isn't visible. I don't know if labels are scrollable, would they be a better option?
Code:
public static void main(String[] args)
{
JFrame win = new JFrame("Window");
win.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
win.setSize(400, 300);
GridBagConstraints c = new GridBagConstraints();
win.setLayout( new GridBagLayout() );
JTextArea master = new JTextArea(1,1);
JTextArea vendor = new JTextArea(1,1);
master.setEditable(false);
vendor.setEditable(false);
master.setPreferredSize( new Dimension(100,20) );
vendor.setPreferredSize( new Dimension(100,20) );
master.setText(/*some really long string*/);
vendor.setText(/*some really long string*/);
JScrollPane mPane = new JScrollPane(master, JScrollPane.VERTICAL_SCROLLBAR_NEVER, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
JScrollPane vPane = new JScrollPane(vendor, JScrollPane.VERTICAL_SCROLLBAR_NEVER, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
mPane.getHorizontalScrollBar().isVisible();
vPane.getHorizontalScrollBar().isVisible();
JButton one = new JButton("Select");
ActionListener select = new SelectButton(master, vendor);
one.addActionListener(select);
JButton two = new JButton("Run");
c.gridx = 0;
c.gridy = 0;
win.add(one, c);
c.gridx = 1;
c.gridy = 0;
win.add(two, c);
c.gridx = 0;
c.gridy = 1;
win.add(master, c);
win.add(mPane, c);
c.gridx = 0;
c.gridy = 2;
win.add(vendor, c);
win.add(vPane, c);
win.setLocationRelativeTo(null);
win.setVisible(true);
return;
}

Don't, ever, use setPreferredSize! This is overriding the information that the JScrollPane needs in order to make decisions about how the components should be scrolled. See Should I avoid the use of set(Preferred|Maximum|Minimum)Size methods in Java Swing? for more details. Instead use the JTextArea(int, int) constructor to provide hints to the JScrollPane, for example JTextArea master = new JTextArea(1, 20);. Any text longer then 20 characters will cause the JScrollPane to display the horizontal scroll bar...
Don't add both the JTextArea AND the JScrollPane to the container. Adding the JTextArea automatically removes it from the JScrollPane, which isn't what you want.
Use GridBagConstaints#gridwidth to control the number of columns a component might expand across to help fix your layout...
For example...
c.gridx = 0;
c.gridy = 1;
c.gridwidth = GridBagConstraints.REMAINDER;
win.add(mPane, c);
c.gridx = 0;
c.gridy = 2;
win.add(vPane, c);
I'm hoping this is a really simple example, if not, you should always make sure that your UI is created and modified from within the context of the EDT. See Initial Threads for more details

Line wrapped JTextArea using too much space with GridBagLayout

I've been trying to get a scrollable JTextArea to appear to the right of a JList where the JTextArea takes up most of the space but leaves a good portion for the JList (3/4 of the frame for the JTextArea, 1/4 for the JList). The problem is that the weights of the constraints seem to be ignored when LineWrap on the JTextArea is set to true.
Without line wrap, the JTextArea takes up about 3/4 of the frame and the JList takes up the other 1/4, which is what I want. But when line wrapping is turned on, the JTextArea attempts to take up as much space as possible and crushes the JList down to the width of the strings it contains. The interesting thing is that this only appears to happen once you resize the window (looks fine initially), and if you type anything into the JTextArea, it slowly expands, pushing the JList back. This has been confusing me to say the least.
I made a screenshot of what it looks like without line wrapping and with line wrapping after resizing the window:
Here's some example code showing you what I mean. Remove the line wrap statements and it'll look fine, but keep them there and you'll see that upon resizing, the JList is squished.
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.*
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel(new GridBagLayout());
JTextArea area = new JTextArea();
DefaultListModel<String> model = new DefaultListModel<>();
JList<String> list = new JList<String>(model);
JScrollPane scroll = new JScrollPane(area,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
for (int i = 0; i < 5; i++)
model.addElement("Example" + i);
area.setLineWrap(true);
area.setWrapStyleWord(true);
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.fill = GridBagConstraints.BOTH;
c.weighty = 1;
c.weightx = 0.3;
panel.add(scroll, c);
c = new GridBagConstraints();
c.gridx = 1;
c.fill = GridBagConstraints.BOTH;
c.weighty = 1;
c.weightx = 0.1;
panel.add(list, c);
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 300);
frame.setVisible(true);
}
}

You can use ipadx to define minimal possible width
c.weightx = 0.1;
c.ipadx=desiredPixelsWidthForTheList;
panel.add(list, c);
UPDATE
Also you can place both in a JSplitPane and define desired proportions.

The short answer is that the text area gets more width than you want because its preferred width is much larger than that of the list.
Keep in mind that weightx doesn't determine what percentage of space a component will occupy but the proportional amount of space that's added to or taken away from the component's size. In this case, for example, the "extra" space is the difference between the frame's width (or more accurately, its content pane's width) which you explicitly set to 500 and the combined widths of the text area and the list. In other words, both the scroll pane / text area and the list will be displayed at their preferred sizes PLUS 75% of the left-over space for the text area and 25% for the list. Again, since the text area's preferred size is large to begin with, it occupies a bigger portion of the screen than what you want.
As a couple of people have already pointed out, a simple way to get the results you want is to explicitly specify the number of rows and columns for the text area. On the other hand, you should avoid explicitly setting a size, preferred or otherwise as discussed in questions like this.
As far as the mysteriously shrinking list goes, I suspect that's a bug in GridBagLayout. It seems to ignore the maximum size of the JList initially but then respects it when it lays out the components as a result of the frame resizing, which is why it suddenly shrinks and then never gets larger again. That's not normally an issue because like JTextArea, a JList is normally contained within a scroll pane, which is something you should probably also consider doing.

try using .setPreferredSize() to components

I have modified your code. Just specified the size of textarea and list like this
list.setPreferredSize(new Dimension(frame.getWidth()/4, frame.getHeight()));
area.setPreferredSize(new Dimension(frame.getWidth()*(3/4), frame.getHeight()));
check the full code below:
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.DefaultListModel;
import javax.swing.JFrame;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
public class Main {
public static void main(String[] args) {
JFrame frame = new JFrame();
JPanel panel = new JPanel(new GridBagLayout());
JTextArea area = new JTextArea();
DefaultListModel model = new DefaultListModel();
JList list = new JList(model);
JScrollPane scroll = new JScrollPane(area,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
for (int i = 0; i < 5; i++)
model.addElement("Example" + i);
frame.setSize(500, 300);
list.setPreferredSize(new Dimension(frame.getWidth()/4, frame.getHeight()));
area.setPreferredSize(new Dimension(frame.getWidth()*(3/4), frame.getHeight()));
area.setLineWrap(true);
area.setWrapStyleWord(true);
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.fill = GridBagConstraints.BOTH;
c.weighty = 1;
c.weightx = 0.3;
panel.add(scroll, c);
c = new GridBagConstraints();
c.gridx = 1;
c.fill = GridBagConstraints.BOTH;
c.weighty = 1;
c.weightx = 0.1;
panel.add(list, c);
frame.add(panel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}

Please suggest me a basic layout to use, other than the GridBag layout

OK I have a panel, and I want to place two panels on to it, left and right, such that the right panel should be double the width of the left side panel.
I want to add a menu to the left side panel, and the details of the selected item will appear in the right side panel.
Secondly, the size of the panels and their components should increase proportionately when the window is expanded (If any methods can be used for the purpose, please suggest!)
I did try to use the GridBagLayout but I think I have not yet been able to grasp it well. So please suggest the simplest layout manager which can serve my purpose.
EDIT:- PROBLEMS WITH WHAT I HAD TRIED WITH THE GRIDBAG
//Set Layout
setLayout(new GridBagLayout());
GridBagConstraints c= new GridBagConstraints();
//Set Layout constraints of components and add them to the MainPanel
c.gridx=0;
c.gridy=0;
c.weightx=0.5;
c.insets= new Insets(5,5,5,5);
c.fill=GridBagConstraints.BOTH;
add(iListPanel);
iListPanel.setBorder(BorderFactory.createTitledBorder("Check") );
GridBagConstraints c1= new GridBagConstraints();
c.gridx=1;
c.gridy=0;
c.weightx=1;
c.insets= new Insets(5,5,5,5);
c.fill=GridBagConstraints.BOTH;
add(iDetailsPanel);
iDetailsPanel.setBorder(BorderFactory.createTitledBorder("Check"));

Of the layout managers that come with Java, I think GridBagLayout is the simplest one that will do that. It's worth the time to learn it, because it's about the only layout manager that's halfway-competent. This should do it:
JPanel panel = new JPanel();
panel.setLayout(new GridBagLayout());
GridBagConstraints c;
JPanel left = new JPanel();
left.setBorder(BorderFactory.createTitledBorder("Left"));
c = new GridBagConstraints();
c.weightx = 1;
c.weighty = 1;
c.fill = c.BOTH;
panel.add(left, c);
JPanel right = new JPanel();
right.setBorder(BorderFactory.createTitledBorder("Right"));
c = new GridBagConstraints();
c.weightx = 2;
c.weighty = 1;
c.fill = c.BOTH;
panel.add(right, c);
However, from the description of your problem, it sounds like JSplitPane will serve you better for this. It's a ready-made component to do more-or-less what you're asking, and has a user-resizeable separator as well. An example:
JSplitPane pane = new JSplitPane();
pane.setResizeWeight(1/3f); // right will be twice size of left
JPanel left = new JPanel();
left.setBorder(BorderFactory.createTitledBorder("Left"));
pane.setLeftComponent(left);
JPanel right = new JPanel();
right.setBorder(BorderFactory.createTitledBorder("Right"));
pane.setRightComponent(right);
Edit: The problem with your original code is that it does not use the constraints.
add(iListPanel);
should be:
add(iListPanel, c);
and likewise for iDetailsPanel.

You want to use a BorderLayout.
panel.add(panelLeft,"West");
panel.add(panelRight,"East");
North, South and Center is also available

How to set the component size with GridLayout? Is there a better way?

I am working on a larger GUI with Java and I am becoming angry on Layout Managers.
I have a "Settings-Panel" with a variable number of JComponents in it (Labels, Buttons, JSpinners, JSliders,...). I just want the following:
JLabel <-> JComponent
JLabel <-> JComponent
JLabel <-> JComponent
...
My Panel has a size of 500px, so that there is enough space for a lot of components. Unfortunately the GridLayout always stretches the size of the Components to the whole Panel, even if I set a MaximumSize for every component. It looks stupid if there are only two buttons each with a height of 250px.
I tried FlowLayout, but I cannot figure out a way to make new lines properly. I tried BoxLayout.Y_AXIS, but the Components are always centered, and Label and Component are not in the same line.
Does anybody know a good and short way with LayoutManagers to handle this properly?

An alternative to other layouts, might be to put your panel with the GridLayout, inside another panel that is a FlowLayout. That way your spacing will be intact but will not expand across the entire available space.

Don't use GridLayout for something it wasn't meant to do. It sounds to me like GridBagLayout would be a better fit for you, either that or MigLayout (though you'll have to download that first since it's not part of standard Java). Either that or combine layout managers such as BoxLayout for the lines and GridLayout to hold all the rows.
For example, using GridBagLayout:
import java.awt.*;
import javax.swing.*;
public class LayoutEg1 extends JPanel{
private static final int ROWS = 10;
public LayoutEg1() {
setLayout(new GridBagLayout());
for (int i = 0; i < ROWS; i++) {
GridBagConstraints gbc = makeGbc(0, i);
JLabel label = new JLabel("Row Label " + (i + 1));
add(label, gbc);
JPanel panel = new JPanel();
panel.add(new JCheckBox("check box"));
panel.add(new JTextField(10));
panel.add(new JButton("Button"));
panel.setBorder(BorderFactory.createEtchedBorder());
gbc = makeGbc(1, i);
add(panel, gbc);
}
}
private GridBagConstraints makeGbc(int x, int y) {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = 1;
gbc.gridheight = 1;
gbc.gridx = x;
gbc.gridy = y;
gbc.weightx = x;
gbc.weighty = 1.0;
gbc.insets = new Insets(5, 5, 5, 5);
gbc.anchor = (x == 0) ? GridBagConstraints.LINE_START : GridBagConstraints.LINE_END;
gbc.fill = GridBagConstraints.HORIZONTAL;
return gbc;
}
private static void createAndShowUI() {
JFrame frame = new JFrame("Layout Eg1");
frame.getContentPane().add(new LayoutEg1());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}

For more complex layouts I often used GridBagLayout, which is more complex, but that's the price. Today, I would probably check out MiGLayout.

In my project I managed to use GridLayout and results are very stable, with no flickering and with a perfectly working vertical scrollbar.
First I created a JPanel for the settings; in my case it is a grid with a row for each parameter and two columns: left column is for labels and right column is for components. I believe your case is similar.
JPanel yourSettingsPanel = new JPanel();
yourSettingsPanel.setLayout(new GridLayout(numberOfParams, 2));
I then populate this panel by iterating on my parameters and alternating between adding a JLabel and adding a component.
for (int i = 0; i < numberOfParams; ++i) {
yourSettingsPanel.add(labels[i]);
yourSettingsPanel.add(components[i]);
}
To prevent yourSettingsPanel from extending to the entire container I first wrap it in the north region of a dummy panel, that I called northOnlyPanel.
JPanel northOnlyPanel = new JPanel();
northOnlyPanel.setLayout(new BorderLayout());
northOnlyPanel.add(yourSettingsPanel, BorderLayout.NORTH);
Finally I wrap the northOnlyPanel in a JScrollPane, which should behave nicely pretty much anywhere.
JScrollPane scroll = new JScrollPane(northOnlyPanel,
JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
Most likely you want to display this JScrollPane extended inside a JFrame; you can add it to a BorderLayout JFrame, in the CENTER region:
window.add(scroll, BorderLayout.CENTER);
In my case I put it on the left column of a GridLayout(1, 2) panel, and I use the right column to display contextual help for each parameter.
JTextArea help = new JTextArea();
help.setLineWrap(true);
help.setWrapStyleWord(true);
help.setEditable(false);
JPanel split = new JPanel();
split.setLayout(new GridLayout(1, 2));
split.add(scroll);
split.add(help);

You need to try one of the following:
GridBagLayout
MigLayout
SpringLayout
They offer many more features and will be easier to get what you are looking for.

I used WrapFlowLayout instead
JPanel yourPanel = new JPanel(new WrapFlowLayout(10, 10);