Develop Reference

JScrollPane doesn't seem to scroll

I'm pretty new to Java Swing. Can someone help me figure out what I am doing wrong? Please correct me anywhere necessary. A good portion of this code was trial and error.
I have a frame, which contains a JPanel. The JPanel is using the "GridBag" layout. The code included revolves around the child JPanel on the right side as seen in the picture. For some reason, I can't seem get my vertical scrollbar working properly.
Here's the code of interest:
/// GridBagConstraints
GridBagConstraints gbc = new GridBagConstraints();
// parent jpanel for scrollpane
scrollPanel = new JPanel();
scrollPanel.setLayout(new BorderLayout());
gbc.gridx = 1;
gbc.gridy = 0;
gbc.weightx = 1.0;
gbc.weighty = 1.0;
gbc.fill = GridBagConstraints.BOTH;
add(scrollPanel, gbc);
// content jpanel for scrollpane
scrollPaneContent = new JPanel();
scrollPaneContent.setLayout(new GridLayout(0, 1, 0, 1));
// scrollPane
scrollPane = new JScrollPane();
scrollPane.setBorder(BorderFactory.createEmptyBorder(0,30,0,0));
scrollPane.setViewportView(scrollPaneContent);
scrollPanel.add(scrollPane, BorderLayout.PAGE_START);
And here is what the program looks like at the moment.
You can see the numbers just go off the screen:
Any help is greatly appreciated! Thank you.

scrollPanel.add(scrollPane, BorderLayout.PAGE_START);
You are attempting to add the scrollPane to the scrollPanel. That is not the way it works.
A JScrollPane is a container, so you need to add the panel containing the components to the scroll pane
JPanel panel = new JPanel(...);
panel.add(....);
panel.add(....);
JScrollPane scrollPane = new JScrollPane( panel );
frame.add( scrollPane );
The above code will add the panel to the "viewport" of the scroll pane.

Java: GridBagLayout unwanted spacing between adjacent x grids

I have this GUI
I have used GridBagLayout for it but I do not know why there is a huge spacing between the Plain Bread checkbox and its corresponding label.
And also, I have tried to increase the spacing along the x-axis only for the button but it has increased along all the components in the x-axis despite resetting the insets (but the spacing between the checkbox between Plain Bread and the label existed before setting the insets for the button).
Here are the codes:
public Bakery(){
super("Bakery Bread Option");
setLayout(new FlowLayout());
panel.setLayout(new GridBagLayout());
add(panel);
GridBagConstraints gbc= new GridBagConstraints();
gbc.insets= new Insets(4,4,4,4);
gbc.gridx=0;
gbc.gridy=0;
panel.add(option_Title, gbc);
gbc.gridx=0;
gbc.gridy=1;
panel.add(check_Plain, gbc);
gbc.gridx=0;
gbc.gridy=2;
panel.add(qty_Plain, gbc);
gbc.gridx=0;
gbc.gridy=3;
panel.add(qty_Brown, gbc);
gbc.insets= new Insets(0,175,0,0);
gbc.gridx=0;
gbc.gridy=4;
panel.add(calc_Btn, gbc);
gbc.insets= new Insets(4,4,4,4);
gbc.gridx=1;
gbc.gridy=1;
panel.add(plain_Bread, gbc);
gbc.gridx=1;
gbc.gridy=2;
panel.add(qtyPlainText, gbc);
gbc.gridx=1;
gbc.gridy=3;
panel.add(qtyBrownText, gbc);
gbc.gridx=2;
gbc.gridy=1;
panel.add(check_Brown, gbc);
gbc.gridx=3;
gbc.gridy=1;
panel.add(brown_Bread, gbc);
calc_Amt calc_Handler= new calc_Amt();
calc_Btn.addActionListener(calc_Handler);
}
EDIT:
This is the GUI I intend to achieve:

there is a huge spacing between the Plain Bread checkbox and its corresponding label.
Because the components are added to different columns.
The width of a column is determined by the width of the largest component in the column. So the text component determines the width of the column, not the label.
If you want the label/check box to be together, you can create a JPanel and add the two components to the panel. Then add the panel to the gridbaglayout.
Or you could have the two text fields use a columnWidth of 2, which means they will span two columns.

Jbuttons inside JPanel with background image in right | bottom corner

Can somebody explain me how can I put few jButtons inside jLabel which have background image like on this image? The main jFrame is undecorated and is set to full screen.
I saw a lot of different examples like
this or like this, but these examples are showing only single button in jPanel.

Personally, I'd avoid using a JLabel for this purpose, it does not calculate it's required size based on it's content, but rather off it's icon and text properties.
This might be a good or bad thing, but it can catch your unawares if you're not aware of it.
Instead, I'd use a customised JPanel, which would allow you to define things like the resize and fill rules, for example and for example
Now, once you have that covered, you need to create a panel of your buttons. I prefer to create a dedicated class, as it makes it easier to isolate functionality and management, but that's me...
public class ButtonPane extends JPanel {
public ButtonPane() {
setLayout(new GridBagLayout());
setBorder(new EmptyBorder(8, 8, 8, 8));
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.insets = new Insets(2, 2, 2, 2);
add(new JButton("Button 1"), gbc);
add(new JButton("Button 2"), gbc);
add(new JButton("Button 3"), gbc);
}
}
Next, you need to add this panel to your background
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setContentPane(backgroundPane);
frame.setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.weightx = 1;
gbc.weighty = 1;
gbc.anchor = GridBagConstraints.SOUTHEAST;
gbc.insets = new Insets(30, 30, 30, 30);
ButtonPane buttonPane = new ButtonPane();
frame.add(buttonPane, gbc);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
Which can generate something like...
Have a look at Laying Out Components Within a Container and How to Use GridBagLayout for some more details

These examples are truly good enough, I think you should just learn more about swing.
For now, You could simply do:
JFrame frame = new JFrame("Hi there");
JButton b1 = new JButton("1");
JButton b2 = new JButton("2");
frame.add(b1);
frame.add(b2);
b1.setBounds(60, 60, 40, 40);
b2.setBounds(10, 10, 40, 40);
frame.setVisible(true); //in case, add frame.setLayout(null);
You can of course add buttons to JPanel instead of JFrame

How to control the size of the panels

I'm learning swing gui and I get this result when I use the following code:-
The code I use :-
private void initUI() {
JTextArea visualize=new JTextArea();
visualize.setEditable(false);
//DEFINE BUTTONS....
JButton[] buttons1={addition,subtraction,division,multiplication};
JButton [] buttons2={expr,date,conversion};
JPanel numerical=new JPanel(new FlowLayout());
numerical.setPreferredSize(new Dimension(350, 50));
for(int i=0;i<buttons1.length;i++){
numerical.add(buttons1[i]);
}
numerical.setBorder(new TitledBorder("Numerical Operations"));
JPanel nonnum=new JPanel(new FlowLayout());
nonnum.setPreferredSize(new Dimension(500, 50));
for(int i=0;i<buttons2.length;i++){
nonnum.add(buttons2[i]);
}
nonnum.setBorder(new TitledBorder("Non-numerical Operations"));
JPanel operations = new JPanel(new BorderLayout(2,2));
operations.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));
operations.setSize(800, 100);
operations.add(numerical,BorderLayout.WEST);
operations.add(nonnum,BorderLayout.EAST);
JTable sheet = new JTable(10,5);
add(visualize, BorderLayout.NORTH);
add(sheet,BorderLayout.SOUTH);
add(operations,BorderLayout.CENTER);
pack();
setSize(1000, 700);
setTitle("Spreadsheet Application");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLocationRelativeTo(null);
}
But what I really want is this:-
My questions :-
Why is the operations panel too long?
How can I change it's height?
Doesn't "operations.setSize(..)" work?

Try using GroupLayout.
I'm also new to swing gui and had similar problems - GroupLayout saved the day
JPanel complete=new JPanel();
GroupLayout gl=new GroupLayout(complete);
complete.setLayout(gl);
gl.setAutoCreateContainerGaps(true);
gl.setHorizontalGroup(gl.createParallelGroup() //this is parallel bcz you need components vertically
.addComponent(visualize) //you MUST add components to both horizontal and vertical groups
.addComponent(operations)
.addComponent(sheet)
);
gl.setVerticalGroup(gl.createSequentialGroup() //NOTE that this is sequential
.addComponent(visualize)
.addComponent(operations)
.addGap(50) //you can add gaps if you want
.addComponent(sheet)
);
add(complete);

Because that's how BorderLayout works, take a closer look at How to Use BorderLayout. The CENTRE position will occupy all the remaining space of the frame, where as the NORTH and SOUTH positions will try and honour the preferred sizes of the components.
You could use a GridBagLayout, which will allow you more control over the layout or use a series of compound layouts.
Something like...
setLayout(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
gbc.weightx = 1;
gbc.fill = GridBagConstraints.BOTH;
add(visualize, gbc);
add(operations, gbc);
gbc.gridy = 1;
add(sheet, gbc);
It is generally discouraged to extend from a top level container like JFrame, instead you should use something like JPanel to define your UIs and then add them to the containers you want. This increases there re-usability and makes it easier to use on different containers
You may also like to take a look at How to Use Scroll Panes

SOME of us find GridBagLayout to be a royal pain, and you may not have to use it to do what you want to do.
The idea behind a layout manager is to let the layout manager control the size and position of its components so that you don't have to futz with them. MP is right, GridBag allows you a lot of control, but that also means you have to get a lot of things right to have it do what you want it to do.
So, an alternative: Make a JPanel to hold the visualize and operations panels; give this new panel a BoxLayout with a Y_AXIS orientation, then add them in the order you want them to appear, top-to-bottom.
Then put sheet in the BorderLayout.CENTER of the JFrame. In fact, I think you'll want to take MP's advice and go through a tutorial on JScrollPane; as best I remember, you create the panel, then create the JScrollPane instance with the panel as a construction parameter, then add the scrollpane instance to the JFrame (in the CENTER, in your case).
Being in the center, it will then expand and contract as the user changes window size.
Good luck. Swing takes some getting used to.

Java Swing GridBagLayout

I've been learning Java Swing using GridBagLayout.
I have a main JFrame and add main JPanel, then I add subsequent JPanels/components to that main JPanel.
But anything I add it always positions to the center of the main panel (including while resize), which is not desired result.
Just a small snippet on the core code:
getContentPane().setLayout(new GridBagLayout());
JPanel panel = new JPanel(new GridBagLayout());
getContentPane().add(panel);
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.anchor = GridBagConstraints.NORTHWEST;
JTextField nameField = new JTextField(10);
panel.add(nameField, gbc)
Any feedback would be appreciated, thanks.

In the future, post a SSCCE when you have a problem. A small "snippet" of code generally doesn't help.
Read the section from the Swing tutorial on How to Use GridbagLayout. The part on "weightx/weighty" will explain why this happens.