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How to keep JPanel at top of parent container at runtime?

I create a parent container onto which I place several JPanel objects, each containing several JButton objects.
I create the parent panel, add the GridBagConstraints then add each child panel to the parent:
final JPanel options = new JPanel(new GridBagLayout());
options.setBorder(new TitledBorder("Select Option"));
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.fill = GridBagConstraints.HORIZONTAL;
gbc.weightx = 1.0;
gbc.anchor = GridBagConstraints.NORTH;
options.add(findPanel, gbc);
options.add(addPanel, gbc);
options.add(changePanel, gbc);
options.add(dropPanel, gbc);
gbc.weighty = 1.0;
options.add(new JPanel(), gbc);
With options.add(new JPanel(), gbc); used to take up the extra space under my wanted panels. Works great....until I want to change the contents of the parent after user interaction:
partnoFai.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae){
options.remove(findPanel);
options.remove(addPanel);
options.remove(changePanel);
options.remove(dropPanel);
options.add(partnoFaiInp, gbc);
gbc.weighty = 1.0;
options.add(new JPanel(), gbc);
frame.pack();
frame.validate();
}
} );
It's adding the new panel, options.add(partnoFaiInp, gbc); to the middle of the parent when I want it at the top. Why wouldn't gbc.anchor = GridBagConstraint.NORTH; keep the new panel in the NORTH of the panel?
Any help is appreciated.

You have to think of the Container in terms of a stack
When you first setup the panel using...
options.add(findPanel, gbc);
options.add(addPanel, gbc);
options.add(changePanel, gbc);
options.add(dropPanel, gbc);
gbc.weighty = 1.0;
options.add(new JPanel(), gbc);
The container has a list of components looking like {findPanel, addPanel, changePanel, dropPanel, JPanel}
When you remove the components using something like...
options.remove(findPanel);
options.remove(addPanel);
options.remove(changePanel);
options.remove(dropPanel);
The container now has a list of components looking like {JPanel}
Then when you add your new component using...
options.add(partnoFaiInp, gbc);
gbc.weighty = 1.0;
options.add(new JPanel(), gbc);
The container now has a list of components looking like {JPanel, partnoFaiInp, JPanel}
So, instead of adding the another "filler" component, you could just specify the insert point of the panel when you add it...
options.add(partnoFaiInp, gbc, 0);
frame.pack();
frame.validate();
The container now has a list of components looking like {partnoFaiInp, JPanel}

Java setBorder breaks component padding

When I set a border color to every item in a JPanel with GridBagLayout, the components collapse.
but when I remove the border off just one component, the padding stays as expected.
What am I doing wrong?
Border Setting:
setBorder(BorderFactory.createLineBorder(Color.decode("#"+Constants.Display.OPTIONS_BORDER_COLOR)));
JPanel:
public class OptionsPanel extends JPanel {
private AddMachineBtn addMachineBtn;
private SearchField searchField;
private SearchBtn searchBtn;
private GridBagConstraints gbc;
public OptionsPanel() {
init();
config();
build();
}
private void init() {
addMachineBtn = new AddMachineBtn("Add Machine");
searchField = new SearchField("Search...");
searchBtn = new SearchBtn("S");
gbc = new GridBagConstraints();
int i = Constants.Display.OPTIONS_PANEL_PADDING;
gbc.insets = new Insets(i, i, i, i);
}
private void config() {
setLayout(new GridBagLayout());
setBorder(BorderFactory.createMatteBorder(0, 0, 1, 0, Color.decode("#"+Constants.Display.OPTIONS_BORDER_COLOR)));
setPreferredSize(new Dimension(0, Constants.Display.OPTIONS_PANEL_HEIGHT));
gbc.gridy = 0;
gbc.weightx = 1;
gbc.weighty = 1;
gbc.anchor = gbc.LINE_START;
}
private void build() {
gbc.gridx = 0;
add(addMachineBtn, gbc);
gbc.weightx = 0;
gbc.gridx = 1;
add(searchField, gbc);
gbc.gridx = 2;
add(searchBtn, gbc);
}
}

I'm not sure about how it affects GridBagLayout, but "In general, when you want to set a border on a standard Swing component other than JPanel or JLabel, we recommend that you put the component in a JPanel and set the border on the JPanel."—setBorder(). There's a related example here.

Yes, layout has no affect to components' size. You may try to change layout (for example to FlowLayout) but situation will be the same.
Swing components obtains its border during initialization from Look'n'Feel.
Insert System.out.println(addMachineBtn.getBorder()); after addMachineBtn creation. You will see that the border already exists
javax.swing.plaf.BorderUIResource$CompoundBorderUIResource
This border provides its own insets for component, and when you replace border by another ones you loose its insets.

If it's really important to keep original components insets and replace border, try to imitate native Swing borders.
For example something like this:
addMachineBtn.setBorder(new CompoundBorder(new LineBorder(Color.red), new EmptyBorder(5, 17, 5, 17)));
Instead of LineBorder put border what you need, EmptyBorder keep the same, just correct insets as needed.

The fix to this was changing the following
setSize(new Dimension(w,h));
setMinimumSize(new Dimension(w,h));
setMaximumSize(new Dimension(w,h));
to
setPreferredSize(new Dimension(w,h));
setMinimumSize(new Dimension(w,h));
setMaximumSize(new Dimension(w,h));

Is it possible to make the elements inside a JPanel with GridBagLayout to start from the top left?

I have a Swing Form that contains a JScrollPane(activityScrollPane) for a JPanel(activityPanel). The panel contains a JTextField and a JButton (that is used to add more fields to the Panel). Now the problem is that the elements start from the center of the panel as in the image below (with the borders marking the activityScrollPane boundary)
Following is the code I am currently using to make the scroll pane and associated components.
//part of the code for creating the ScrollPane
final JPanel activityPanel = new JPanel(new GridBagLayout());
gbc.gridx=0;
gbc.gridy=0;
JScrollPane activityScrollPane = new JScrollPane(activityPanel);
//adding activity fields
activityFields = new ArrayList<JTextField>();
fieldIndex = 0;
activityFields.add(new JTextField(30));
final GridBagConstraints activityGBC = new GridBagConstraints();
activityGBC.gridx=0;
activityGBC.gridy=0;
activityGBC.anchor = GridBagConstraints.FIRST_LINE_START;
activityPanel.add(activityFields.get(fieldIndex),activityGBC);
fieldIndex++;
JButton btn_more = (new JButton("more"));
activityGBC.gridx=1;
activityPanel.add(btn_more,activityGBC);
How can I make the JTextField and the JButton or for that matter any component to appear on the top left corner of the JScrollPane. I have already tried using
activityConstraints.anchor = GridBagConstraints.NORTHWEST;
as pointed in the SO post, but it does not at all seem to work.

You simply forgot to provide any weightx/weighty values, atleast one having a non-zero value will do. have a look at this code example :
import java.awt.*;
import javax.swing.*;
public class GridBagLayoutDemo
{
private JTextField tfield1;
private JButton button1;
private void displayGUI()
{
JFrame frame = new JFrame("GridBagLayout Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setLayout(new GridBagLayout());
tfield1 = new JTextField(10);
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.FIRST_LINE_START;
gbc.weightx = 1.0;
gbc.weighty = 1.0;
gbc.gridx = 0;
gbc.gridy = 0;
gbc.fill = GridBagConstraints.HORIZONTAL;
contentPane.add(tfield1, gbc);
button1 = new JButton("More");
gbc.gridx = 1;
gbc.gridy = 0;
gbc.fill = GridBagConstraints.NONE;
contentPane.add(button1, gbc);
frame.setContentPane(contentPane);
frame.pack();
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new GridBagLayoutDemo().displayGUI();
}
});
}
}
Latest EDIT : No spacing along Y-Axis
import java.awt.*;
import javax.swing.*;
public class GridBagLayoutDemo
{
private JTextField tfield1;
private JButton button1;
private JTextField tfield2;
private JButton button2;
private void displayGUI()
{
JFrame frame = new JFrame("GridBagLayout Demo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel contentPane = new JPanel();
contentPane.setLayout(new GridBagLayout());
tfield1 = new JTextField(10);
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.FIRST_LINE_START;
gbc.weightx = 1.0;
//gbc.weighty = 0.2;
gbc.gridx = 0;
gbc.gridy = 0;
gbc.fill = GridBagConstraints.HORIZONTAL;
contentPane.add(tfield1, gbc);
button1 = new JButton("More");
gbc.gridx = 1;
gbc.gridy = 0;
gbc.fill = GridBagConstraints.NONE;
contentPane.add(button1, gbc);
tfield2 = new JTextField(10);
gbc.weightx = 1.0;
gbc.weighty = 0.2;
gbc.gridx = 0;
gbc.gridy = 1;
gbc.fill = GridBagConstraints.HORIZONTAL;
contentPane.add(tfield2, gbc);
button2 = new JButton("More");
gbc.gridx = 1;
gbc.gridy = 1;
gbc.fill = GridBagConstraints.NONE;
contentPane.add(button2, gbc);
JScrollPane scroller = new JScrollPane(contentPane);
frame.add(scroller);
frame.pack();
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
new GridBagLayoutDemo().displayGUI();
}
});
}
}

Sorry as my answer me be on the off-side of what you have asked, but why dont you use GroupLayout instead of GridBag Layout, thats much more easier to handle

try it with BorderLayout: controls.setLayout(new BorderLayout()); and then apply it for your JPanel controls.add(yourPanel, BorderLayout.PAGE_START);
I also have problems with GridBagLayout so i solved it with BorderLayout and it works so fine.
So i wrote for your little example:
private void initComponents() {
controls = new Container();
controls = getContentPane();
controls.setLayout(new BorderLayout());
panel = new JPanel();
panel.setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
field = new JTextField(20);
c.gridx = 0;
c.gridy = 0;
panel.add(field, c);
one = new JButton("Go!");
c.gridx = 1;
c.gridy = 0;
panel.add(one, c);
controls.add(panel, BorderLayout.PAGE_START);
}
Hope it helps!

I think this could be simple and possible, you can
put Nested JPanel to the JScrollPane
to this JPanel
put JPanels contains JComponent to the GridLayout (notice about scrolling, you have to change scrolling increment)
or use most complex JComponents as
put JPanels contains JComponent as Item to the JList
put JPanels contains JComponent as row to the JTable (with only one Column, with or without TableHeader)

Add one panel at the right and one at the bottom.
Right Panel:
Set Weight X to 1.0.
Set Fill to horizontal.
Bottom Panel:
Set Weight Y to 1.0.
Set Fill to vertical
There may be better ways to that, but this one worked for me.

Not able to add 3 JPanels to a main panel

I have 3 JPanels and I want to place them all in one JPanel. I used the GridBagLayout for the main panel. But only one panel is getting added. Why might this be?
gblayout=new GridBagLayout();
gbc=new GridBagConstraints();
panel1Customizer();
panel2customizer();
panel3Customizer();
setLayout(gblayout);
gbc.fill=GridBagConstraints.HORIZONTAL;
gbc.anchor=GridBagConstraints.NORTHWEST;
gbc.weightx=1;
gbc.weighty=1;
gbc.gridheight=GridBagConstraints.REMAINDER;
add(panel1, gbc);
add(panel2, gbc);
gbc.gridwidth=GridBagConstraints.REMAINDER;
add(panel3, gbc);
The customizer methods are ones which add items into these panels.

I am not sure but I think you need to add a GridBagConstraints to your GridBagLayout. Try look at this site to get the idea on how to work with GridBagLayout:
link
Or maybe just use another Layout for your JFrame, maybe BorderLayout or GridLayout to arrange your Panels correctly

You should change gbc.gridx and/or gbc.gridy to be different for each panel

you have to read How to Use GridBagLayout, examples for that here and GridBagConstraints, change your gbc.fill=GridBagConstraints.HORIZONTAL;, if you have problem(s) with JComponent's Size then add setPreferedSize(); for example
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.*;
public class GBLFillBoth extends JFrame {
private static final long serialVersionUID = 1L;
public GBLFillBoth() {
JPanel panel = new JPanel();
GridBagLayout gbag = new GridBagLayout();
panel.setLayout(gbag);
GridBagConstraints c = new GridBagConstraints();
JButton btn1 = new JButton("One");
c.fill = GridBagConstraints.BOTH;
//c.fill = GridBagConstraints.HORIZONTAL;
c.anchor=GridBagConstraints.NORTHWEST;
c.gridx = 0;
c.gridy = 0;
c.weightx = 0.5;
c.weighty = 0.5;
panel.add(btn1, c);
JButton btn2 = new JButton("Two");
c.gridx++;
panel.add(btn2, c);
//c.fill = GridBagConstraints.BOTH;
JButton btn3 = new JButton("Three");
c.gridx = 0;
c.gridy++;
c.gridwidth = 2;
panel.add(btn3, c);
add(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
pack();
setVisible(true);
}
public static void main(String[] args) {
GBLFillBoth gBLFillBoth = new GBLFillBoth();
}
}

You might consider using a MigLayout instead, the code is much simpler:
panel1Customizer();
panel2customizer();
panel3Customizer();
setLayout(new MigLayout("fill, wrap 3"));
add(panel1, "grow");
add(panel2, "grow");
add(panel3, "grow");

How to make Java Swing components fill available space?

I cannot seem to get my Java Swing components to work together correctly.
What I want to do, is have a JPanel fill ALL the space available inside a JTabbedPane. At the moment, my setup is as follows:
public class Gui extends JFrame {
private final EventBus eventBus = EventBus.getInstance();
private final ToolkitUtil toolkitUtil;
private final Menu menu;
private final InfoBar infoBar;
private final JTabbedPane pane;
...
private void buildLayout() {
GridBagConstraints gbc = new GridBagConstraints();
setJMenuBar(menu);
add(pane, BorderLayout.CENTER);
add(infoBar, BorderLayout.SOUTH);
pane.addTab("Plugins", new PluginPanel());
}
}
public class PluginPanel extends JPanel {
private final JPanel modelPanel;
private final JPanel editorPanel;
public PluginPanel() {
setLayout(new GridBagLayout());
modelPanel = new JPanel(new GridBagLayout());
editorPanel = new JPanel(new GridBagLayout());
buildLayout();
}
private void buildLayout() {
GridBagConstraints gbc = new GridBagConstraints();
modelPanel.setBorder(BorderFactory.createTitledBorder("Models"));
editorPanel.setBorder(BorderFactory.createTitledBorder("Editors"));
gbc.gridx = 0;
gbc.fill = GridBagConstraints.BOTH;
modelPanel.add(new JLabel("test label"), gbc);
add(modelPanel, gbc);
gbc.gridx = 1;
add(editorPanel, gbc);
}
}
This creates a windows that is my desired size (dynamically proportional to the screen size, not included in above code). The tab panel that is placed in the center is expanded to fill all the space required, which is exactly what I want. But, the panels I add inside the tab panel are only as big as their content. If I add labels or anything, it only grows as big as the components. I want them to always be expanded to fill the tab panel.

The easiest way is to use a BorderLayout and put the component in the CENTER position.

Try setting the weights of the GridBagConstraints to non-zero values:
gbc.weightx = gbc.weighty = 1.0;

Set MinimumSize of your container to preferred size you want, then set ContentPane of container with your panel.
setMinimumSize(new Dimension(width,height));
setContentPane(new MyPanel());
This code works for all layouts.
Or simply call for your container:
setContentPane(new MyPanel());
This code works for BorderLayout or Free Design