making a full size panel, with grid bag layout - java

I am making a program with 3 JSliders, for r,g,b and i want to add a panel that will change it's color for the chosen color in the sliders, everything works for me except one thing, I don't know how to make the panel in the full size of the screen, this is the best I could do, but this is still kind of small and I want to make the panel full size. can any one show me how to do it?
The program is kind of long so I will only send the part of the gridbaglayout and the panel.
private JPanel panel;
public delta(){
setLayout(new GridBagLayout());
GridBagConstraints c = new GridBagConstraints();
panel = new JPanel();
panel.setBackground(new Color(0 ,0 ,0));
c.fill = GridBagConstraints.HORIZONTAL;
c.gridx = 2;
c.gridy = 6;
c.gridwidth = 3;
c.gridheight = 3;
add(panel ,c);

Simply add your panel to Jframe
jframe.add(yourpanel)
This code without any Layout will fill the window.
Edit:
JFrame frame = new JFrame();
frame.setSize(500,500);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel label = new JLabel("HELLO");
frame.add(label);
This fills the JFrame with JLabel.

Related

How do I make two JLabels on opposite sides of the screen?

I'm trying to make something that looks like this:
As you can see, I want the labels on opposite sides of each other on the same line in the same parent container.
I tried using the GridBagLayout, and here is my code:
JPanel cont = new JPanel();
JLabel left = new JLabel("left");
JLabel right = new JLabel("right");
GridBagConstraints gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.WEST;
cont.add(left, gbc);
gbc = new GridBagConstraints();
gbc.anchor = GridBagConstraints.EAST;
cont.add(right, gbc);
You can use GridBagLayout, but I find using the constraints painful and sometimes unpredictable. This is easier with GridLayout and specifying the justification of the JLabel.
Here's an example that puts two JLabels in a row as in your drawing:
JPanel labelrow = new JPanel(new GridLayout(1,2));
JLabel left = new JLabel("left side", JLabel.LEFT);
JLabel right = new JLabel("right side", JLabel.RIGHT);
You can do the same with other controls, like buttons, if you put them inside JPanels with FlowLayouts that are left and right-justified.
Here's an example showing it with buttons off to each side:
JPanel buttons = new JPanel(new GridLayout(1,2));
JPanel left = new JPanel(new FlowLayout(FlowLayout.LEFT));
JPanel right = new JPanel(new FlowLayout(FlowLayout.RIGHT));
left.add(new JButton("Left"));
right.add(new JButton("Right"));
buttons.add(left);
buttons.add(right);

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.

JScrollPane not getting larger when JLabels are added to panel

my problem is that although the scroll bar is appearing on the specific panel I want it to it's not extending as labels are added. I would like it to extend when the labels start going off the panel that they are being added to.
I have a main JPanel 'panel' which uses GridBagLayout, within that I have 5 other panels, the ones that needs a scroll bar is boardPanel which has null value for setLayout()
panel = new JPanel();
panel.setLayout(new GridBagLayout());
...
1Panel = new JPanel();
1Panel.setPreferredSize(new Dimension(480, 800));
1Panel.setLayout(null);
scrollPanel = new JScrollPanel(1Panel, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
...
c.weighty = 1.0;
c.weightx = 0.6;
c.gridx = 0;
c.gridy = 0;
c.gridheight = 3;
panel.add(scrollPanel, c);
...
I hope this is enough information, thank you so much for your help in advance.
Don't use a null layout!!!
Don't use setPreferredSize()!!!
Scrollbars will appear when the preferred size of the component is greater than the size of the scroll pane. By hardcoding a size you break this functionality.
Use a layout manager and the preferred size will change dynamically as you add components to the panel.
Read the Swing tutorial on Layout Managers

GridBagLayout align textField?

I want to shorten my text field so it doesn't stretch to to the end of my jframe so this is how it looks now:
How do control the width of the textfield so it does't streatch like that I tried setPreferedSize() and setSize() yet they didn't work??
#Override
public void run() {
JFrame frame = new JFrame("Test Calculator");
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
frame.setSize(500, 500);
JPanel panel = new JPanel(new GridBagLayout());
frame.getContentPane().add(panel, BorderLayout.NORTH);
GridBagConstraints c = new GridBagConstraints();
JLabel testLabel = new JLabel("Enter Score For Test 1: ");
c.gridx = 0;
c.gridy = 0;
c.anchor = GridBagConstraints.WEST;
c.fill = GridBagConstraints.BOTH;
c.insets = new Insets(40, 15, 15, 0);
panel.add(testLabel , c);
JTextField txtField1 = new JTextField("TextField");
c.gridx = 1;
c.gridy = 0;
c.fill = GridBagConstraints.HORIZONTAL;
c.weightx = .5;
panel.add(txtField1 , c);
}
You're telling the layout that the text field must fill horizontally, so that's what it does. Replace
c.fill = GridBagConstraints.HORIZONTAL;
by
c.fill = GridBagConstraints.NONE;
First and foremost, get rid of this:
frame.setSize(500, 500);
Instead let your components and layout managers size themselves by calling pack() on your JFrame after filling it and before setting it visible.
Next, consider either adding an empty border around your main container, or else adding an empty JLabel to your GridBagLayout using container.
You can also give your JTextField appropriate insets to give a cushion around it.
c.insets = new Insets(40, 15, 15, 40);
panel.add(txtField1, c);
You can change how many columns a particular component takes up by changing GridBagConstraints gridwidth field.
//this would make the next component take up 2 columns
c.gridwidth = 2;
You could have a jpanel and set its dimensions and layout, then add the elements to that panel and add the panel to your jframe.
There are different layout types that can be used depending on what you need to be done. I usually like to use Box's. They have methods that allow you to create horizontal/vertical struts, create rigid areas(this is what I usually use)
Box box1 = Box.createHorizontalBox();
Box box2 = Box.createVerticalBox();
box1.add(Box.createRigidArea(new Dimension(30,0)));
box1.add(testLabel);
box1.add(Box.createRigidArea(new Dimension(30,0)));
box1.add(txtField1);
box1.add(Box.createRigidArea(new Dimension(30,0)));
box2.add(Box.createRigidArea(new Dimension(0,30)));
box2.add(box1);
box2.add(Box.createRigidArea(new Dimension(0,30)));
JFrame.add(box2);
Check this link out for descriptions and how to use all the different kinds of layouts: http://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html

How does GridBagLayout determine size of container

I am using a JDialog with GridBagLayout. Since this layout determines the container and component size automatically, I have not used setSize on anything. However, when the GUI is drawn, it seems to be stretching the container unnecessarily.
Why does GridBagLayout not size the container to "just as much as needed"? Basically I want the dialog size to be just as big as the table inside. Here is the code snippet:
public class GridBagLayoutTester
{
public static void main(String[] args)
{
JDialog mDialog = new JDialog();
JPanel panel1 = new JPanel();
panel1.setLayout(new GridBagLayout());
// Create a table to be added to the panel
JTable table = new JTable(4,4);
JScrollPane scrollpane = new JScrollPane(table);
scrollpane.setBorder(BorderFactory.createLineBorder(Color.ORANGE, 5));
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = gbc.gridy = 0;
gbc.fill = GridBagConstraints.NONE;
gbc.anchor = GridBagConstraints.FIRST_LINE_START;
// Add table to the panel
panel1.add(scrollpane, gbc);
mDialog.add(panel1, BorderLayout.CENTER);
// Display the window.
mDialog.pack();
mDialog.setVisible(true);
}
}
You have to set the preferred size of components when the default sizing isn't what you want.
Change your program to add these lines:
// Display the window.
mDialog.pack();
Dimension d = table.getPreferredSize();
d.width += 16;
d.height += 10;
scrollpane.setPreferredSize(d);
mDialog.pack();
mDialog.setVisible(true);
The additional width of 16 accommodates the border and vertical scroll bar.
The additional height of 10 accommodates the border.

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