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JButton in GridBagLayout in a JPanel

I am learning swing from past week, I have some issue with GridBagConstraints to put one button in top left corner but all other buttons in default in GridBagConstraints ?
I am using code that like not original but states the problem
import java.awt.*;
import javax.swing.*;
#SuppressWarnings("serial")
class MyPanel extends JPanel
{
JButton menu = new JButton("Menu"), button = new JButton("Puzzle");
GridBagConstraints gbc1 = new GridBagConstraints(), gbc2 = new GridBagConstraints();
private void setup()
{
gbc1.anchor = GridBagConstraints.FIRST_LINE_START;
gbc2.anchor = GridBagConstraints.CENTER;
gbc2.weightx = 1.0;
gbc2.weighty = 1.0;
}
public MyPanel()
{
this.setLayout(new GridBagLayout());
this.setup();
this.button.setPreferredSize(new Dimension(250, 140));
this.add(menu, gbc1);
this.add(button, gbc2);
}
}
#SuppressWarnings("serial")
public class Test extends JFrame
{
public Test()
{
this.setTitle("Test");
this.setContentPane(new MyPanel());
this.setResizable(false);
this.setSize(800, 600);
this.setVisible(true);
}
public static void main(String args[])
{
SwingUtilities.invokeLater(() -> new Test());
}
}
output
I want menu is top corner.
I read from here but i did not understand this Could you please explain GridBagConstraints for how to do that.
I Hope that problem is clear to understand, if not please let me know in comments.
EDIT:
#camickr suggestion works but a little problem, the Puzzle Button is not in extract center.
Thanks.

By default the GridBagLayout will display all the components centered horizontally and vertically, unless one of the components has a weightx/weighty value not equal to 0. Then that component will fill the extra space in the frame.
So if you want one component at the "top/left" and one in the "center", you need to:
use the "anchor" constraint. It will be different for both components.
the component in the center will need to use the "weightx/weighty" constraints.
However, an easer solution might be to use a combination of panels with different layout managers.
For example:
JPanel menuPanel = new JPanel( new FlowLayout(FlowLayout.LEFT) );
menuPanel.add(menuButton);
JPanel centerPanel = new JPanel( new GridBagLayout() );
centerPanel.add(puzzle, new GridBagConstraints());
frame.add(menuPanel, BorderLayout.PAGE_START);
frame.add(centerPanel, BorderLayout.CENTER);
So now the "top" of the frame will contain a panel with components displayed from the left and the "center" of the frame will contain your puzzle centered in the remaining space of the frame.
Edit:
I solved it but put gridx and gridy to 0 in center component, but i did not completely understand the setttings
Well I mentioned that you would need to use the gridx/gridy constraints. You should always use those constraints as it is very obvious what grid you want to add the component to. The examples from the tutorial always specify those values.
Using gridx/gridy both equal to 0, does not really make sense. The effect is that you have two components trying to share the same grid.
Remove the setResizable(false) statement and shrink the size of the frame to see how the button repositions itself.
It is not normal that two components share the same grid. Normally you would have the menu on the first row and the button on the second row. This will center the button horizontally in the frame and vertically in the space below the menu.
What you are doi

GridBagLayout is not working when I add it to the JFrame

I'm having some issues with my GridBagLayout. I have created a JPanel (in this case it's called mainPanel), whose layout has been set to GridBagLayout. I have specified the constraints for each JButton, and added the constraints to each button. Now, when I run my code, the buttons are always next to each other, irrespective of the gridx/gridy value that I indicate in the constraints. Furthermore, the buttons are always at the center of the JFrame, when I would like one button to appear at the top right, top left, and south.
import javax.swing.*;
import java.awt.*;
public class test {
public static void main (String[] args) {
myJFrame test = new myJFrame();
}
}
class myJFrame extends JFrame {
public myJFrame () {
setSize(500,500);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainPanel myPanel = new mainPanel();
add(myPanel);
setVisible(true);
}
}
class mainPanel extends JPanel {
public mainPanel(){
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
c.anchor = GridBagConstraints.NORTHWEST;
c.gridx = 1000;
c.gridy= 1;
add(new JButton("1"),c);
c.anchor = GridBagConstraints.NORTHEAST;
c.gridx = 100;
c.gridy= 1;
add(new JButton("2"),c);
c.anchor = GridBagConstraints.SOUTH;
c.gridx = 200;
c.gridy= 1;
add(new JButton("3"),c);
}
}
This is what i get when i run the code

Now, when I run my code, the buttons are always next to each other, irrespective of the gridx/gridy value that I indicate in the constraints.
Correct, you can't just specify random cells. A component must be located in each cell.
Furthermore, the buttons are always at the center of the JFrame,
Yes, this is the default behaviour if you don't specify a weightx/weighty constraint.
Read the section from the Swing tutorial on How to Use GridBagLayout for more information on constraints and working examples.
Why are you picking random x locations like 100, 200, 1000? Maybe a horizontal BoxLayout would be a better layout manager. You can add the components and then add space between them:
panel.add( button1 );
panel.add( Box.createHorizonalStrut(100);
panel.add( button2 );
panel.add( Box.createHorizonalStrut(200);
Or maybe use a FlowLayout and specify the "gap" between each component.

Swing Components in Different Classes

probably a simple question here working on learning to make a GUI using swing and making mild headway but hit another speed bump. I am trying to keep GUI components grouped in different classes to keep my classes small and allow a more flexible GUI, but I have one component built how do I call it to my main class. Posted below is code to make the frame and the component. I would imagine there is an issue with the way I am calling but am running out of ideas on how else to call it. Any thoughts would be appreciated.....Wasn't very clear with the question trying to add the component to the JFrame in frmMainMenu, issue is that the component doesn't appear in the Frame when run currently
Main Class with JFrame
public class frmMainMenu {
public static void main(String main[]){
//Create Frame
JFrame frmMainMenu = new JFrame();
//Define Layout Manager
GridBagLayout gridBag = new GridBagLayout();
GridBagConstraints c = new GridBagConstraints();
frmMainMenu.setLayout(gridBag);
//Add Components
//Create Left Container
c.fill = GridBagConstraints.VERTICAL;
c.weighty = 1;
c.gridx = 0;
c.gridy = 1;
c.ipadx = 30;
frmMainMenu.add(new comLeftToolBar(),c);
frmMainMenu.setExtendedState(JFrame.MAXIMIZED_BOTH);
frmMainMenu.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
//Display Frame
frmMainMenu.setVisible(true);
}
}
Component Code
public class comLeftToolBar extends JPanel{
public comLeftToolBar() {
JPanel comLeftContainer = new JPanel();
GridBagLayout leftGridBag = new GridBagLayout();
comLeftContainer.setLayout(leftGridBag);
GridBagConstraints b = new GridBagConstraints();
JToolBar comLeftToolBar = new JToolBar(JToolBar.VERTICAL);
b.gridx = 0;
b.gridy = 0;
b.ipady = 50;
JButton comNavButton = new JButton();
JButton comProButton = new JButton();
comLeftToolBar.add(comNavButton);
comLeftToolBar.add(comProButton);
comLeftContainer.add(comLeftToolBar,b);
comLeftContainer.setBorder(BorderFactory.createLineBorder(Color.black));
}
}

issue is that the component doesn't appear in the Frame when run currently
Your class is a panel. But then you create another panel (comLeftContainer) and add components to this panel. But you don't add any components to the ComLeftToolBar panel so it remains empty.
For a simple solution, at the bottom of your class you can use:
add( comLeftContainer );
Of course this is not the best solution. This will give you a structure of:
JPanel
JPanel
JToolbar
button
button
There is no need to have such a complicated structure. A toolbar is a component that be added directly to the frame.
If you want to create a class that you can add to the frame then take a look at the Swing tutorial on How to Use Tool Bars for a better structure.

Several similar panels GUI Java

I'm creating GUI and I don't know how to resolve my problem. What I'd like to do is to create several panels from PanelClass like i did in Main.
I don't know how:
Name buttons in my Panels and gave them some functionality (Like i was trying with button b1)
Add to panel3 additional labels, and buttons.
My main class
public class Main {
JFrame f;
PanelClass panel1, panel2, panel3;
JButton b1, b2;
public Main() {
b1 = new JButton("asasa");
f = new JFrame();
f.setSize(300, 300);
f.setLayout(new GridBagLayout());
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
panel1 = new PanelClass(b1, b2, panel1);
panel2 = new PanelClass(b1, b2, panel2);
panel3 = new PanelClass(b1, b2, panel3);
f.add(panel1);
f.add(panel2);
f.add(panel3);
}
public static void main(String[] args) {
Main m = new Main();
}
}
My Panel class
public class PanelClass extends JPanel {
public PanelClass(JButton btn, JButton btn1, JPanel p) {
super();
p = new JPanel(new GridBagLayout());
btn = new JButton();
btn1 = new JButton();
GridBagConstraints c = new GridBagConstraints();
c.gridx = 0;
c.gridy = 0;
p.add(btn, c);
c.gridx = 0;
c.gridy = 1;
p.add(btn1, c);
add(p);
}
}

A component can only exist in one visible container at a time (unless it is being used as a flyweight renderer). So putting the same buttons into 3 panels will not work.
The code passes a button(s) in the constructor of PanelClass which is(are) ignored. Instead 2 new button instances are created. Just assign the passed buttons to the ..I was going to say 'class level attributes' when I noted they were not. Entirely remove
btn = new JButton(); and the text passed in the button constructor will appear.
For events, see How to Write an Action Listener.

Try to read the official Swing tutorial. It explains how to add panels, labels, etc.
To edit label names you could use setText(String name) method. To add functionalities to buttons you must implement a listener in each one. Add labels like you do in other panels, I don't see the problem.

To add "events" like click and mouse hovers etc - you must implement the correct "Listener" for the Widget. Go through any good tutorial on Swing and it will tell you everything about it. Widgets on screen are regular objects as well, so they can be added to "Collections", iterated and played around with, like regular objects. Take note of THREAD complexities and warning 'Cross-Thread invocation is Injurious To Your Program'.

Issue with JPanel as scrollable

I am developing a java JApplet to display few 10s of check boxes in scrollable pane. I included these check boxes in JPanel and added this panel on JScrollPane which is added in current ContentPane of applet. Content pane also has few other components like JTextArea, Button and Label. I would see the scroll bar but when I do scrolling, check boxes are scrolled outside of scrollpane and laid over other adjacent components. I tried setPreferredSize() with no success. What could be the issue with scrolling?
My code bites looks like:
public void init(){
contentPane = this.getContentPane();
GridBagLayout grrdbag = new GridBagLayout();
GridBagConstraints components = new GridBagConstraints();
contentPane.setLayout(gridbag);
//button, textarea and label components here
//checkboxes here
components = new GridBagConstraints();
components.anchor = GridBagConstraints.EAST;
contentPane.add(new Label("Data:", Label.RIGHT), components);
components = new GridBagConstraints();
components.gridwidth = GridBagConstraints.REMAINDER;
components.weighty = 1;
components.fill = GridBagConstraints.BOTH;
checkboxesPanel.setLayout(new BoxLayout(checkboxesPanel, BoxLayout.Y_AXIS));
conflictScrollPane = new JScrollPane(checkboxesPanel,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
contentPane.add(conflictScrollPane, components);
}
//create check boxes
public void displayboxes(){
checkboxes = new Checkbox[150];
for(int j=0;j<150;j++){
checkboxes[j] = new Checkbox("This is test data for check box here.",null,false);
checkboxesPanel.add(checkboxes[j]);
checkboxesPanel.revalidate();
}
repaint();
validate();
}
//start method
public void start() {
displayboxes();
repaint();
validate();
}

If your example is to believed, you are mixing heavy weight and light weight components. My basic recommendation is, don't. They don't play nice together.
Change your references to Checkbox to JCheckBox instead.
Check out for more info
http://java.sun.com/products/jfc/tsc/articles/mixing/
http://java-antony.blogspot.com.au/2007/07/swing-vs-awt-or-lightweight-vs.html
Shane