Develop Reference

How to make a Jframe containing a Jpanel scrollable?

So I have this JFrame that contains a JPanel and in there I add JLabels with information I want but since I'll be adding labels all the time at some point the text is too long to appear so I want to add a scrollbar. Basically I want to make my JFrame with a JPanel in it scrollable. I have this code but my problem is that even though the scrollbar appears but it doesnt move and doesn't really work when the text is a lot, meaning the text still gets cut out and the scrollbar is there not moving. Does anyone know how to fix this?
import javax.swing.*;
import java.awt.*;
import java.util.*;
public class Bar {
JFrame info = new JFrame("Information");
JLabel ballinf = new JLabel();
JPanel contentPane = new JPanel();
JScrollPane scrolling = new JScrollPane();
public Bar(){
contentPane.setOpaque(true);
contentPane.setBackground(Color.WHITE);
contentPane.setLayout(null);
scrolling = new JScrollPane(contentPane,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
info.add(scrolling);
info.setSize(750, 600);
info.setLocationByPlatform(true);
info.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
info.setVisible(true);
}
public void adding(int pos){
ballinf = new JLabel("Something ",JLabel.CENTER);//assume the text will be bigger here and have more info
ballinf.setSize(700, 30);
ballinf.setForeground(Color.green);
ballinf.setLocation(5, 5+pos);
contentPane.add(ballinf);
info.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
info.setVisible(true);
}
public static void main(String[] args){
Bar stats = new Bar();
stats.adding(0);
stats.adding(20);//this will be done in a for loop for more than 2 times so the text ends up to be a lot
}
}

contentPane.setLayout(null);
Don't use a null layout!!!
You need to use an appropriate layout manager. Read the section from the Swing tutorial on Layout Managers for more information and working examples. The layout manager will then determine the preferred size of the panel as you add components to the panel.
The scrollpane will then display the scrollbars when necessary.
If you dynamically add components to the panel (after the GUI is visible) then the code should be something like:
panel.add(...);
panel.revalidate();
panel.repaint();

Aligning JButton

I have to align a button on my program to the exact middle, the current code I have runs it but displays the button as large as the program, I am wanting a center button that is a specific size, here is what I tried
/**
* Created by Timk9 on 11/04/2016.
*/
import javax.swing.*;
import java.awt.*;
public class Test extends JFrame {
{
JFrame window = new JFrame("Test");
window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
window.setResizable(true);
window.setSize(600, 600);
window.setVisible(true);
window.setLocationRelativeTo(null);
JPanel p = new JPanel(new GridBagLayout());
//Button does not appear until I resize the program?
JButton b1 = new JButton("Click here");
GridBagConstraints c = new GridBagConstraints();
p.add(b1);
window.add(p);
}
public static void main(String[] args) {
new Test();
}
}

JPanel p = new JPanel(new GridBagLayout());
You create a panel with a GridBagLayout which is a good layout manager to use to center the component.
p.add(b1);
But then you add the button to the panel without using any contraints.
The code should be:
p.add(b1, c);
//Button does not appear until I resize the program?
All components should be added to the frame BEFORE the frame is made visible. The setVisible(...) statement should be the last statement of the constructor.
Also could you point out which part is an instance initializer block, I thought I was using a constructor
See the FrameDemo example from the Swing tutorial on How to Make Frames for a better way to structure your code so you follow Swing conventions. Start with the working code and make the changes to add your panel containing the button, instead of using the JLabel. Note you no longer need to use the getContentPane() method, you can just add the panel directly to the frame.

It is the LayoutManager that defines how components are layed out where and how big. GridLayout which you are using e. g. divides the available space in equal grid fields and makes the components completely fill this space which is why your button is as big as your application. See here for more info about LayoutManagers: https://docs.oracle.com/javase/tutorial/uiswing/layout/visual.html
Btw. your code is not compilable: new JButton("he"),JButton.ALIGN_CENTER)

Putting everything into a JFrame

I want to know how to put put console output into a JFrame. For example, putting this output into a JFrame:
import static java.lang.System.out;
public class frame{
public static void main(String [] args){
out.println("hello");
}
}
How is it possible?

You need to set up the JFrame first.
JFrame frame = new JFrame("title");
Then, set the properties of the JFrame:
frame.setSize(1280,720); //Sets the program's size
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); //Tells the program to exit on close
frame.setResizable(true); //Tells the program if resizing is enabled
Then, create a panel to store the components:
JPanel p = new JPanel();
After that, you must add the panel to the JFrame like so:
frame.add(p);
Then, with that done, you can use the components supplied in the swing framework, and add them to the panel. A reference for these components can be found here: http://docs.oracle.com/javase/tutorial/uiswing/components/componentlist.html.
To create a component, use the following code:
JLabel label = new JLabel();
Then, use it's build in functions to change it:
label.setText("new text");
Then, once again, to add a component to a panel, use the panel's add() method:
panel.add(label);
Those are just the basics of making a GUI with java. A full tutorial can be viewed here:
http://docs.oracle.com/javase/tutorial/uiswing/
Good Luck!

I can help you with this, but let me please fix some syntax errors you have. When you put the import, an import can't be static (that I know of) and when you want to print out something using "System.out.print" or "System.out.println" you MUST include the "System" part of the line. If you want to add text to a a JFrame use the JLabel to import both just do this bit of code:
import javax.swing.*;
That should import all of your swing elements such as JLabel and JFrame and JPanel, and try this code it will make a window that will have a button and a label. The button doesn't do anything in this code:
import javax.swing.*;
public class main{
public static void main(String[] args)
{
/*
* Creates the frame, makes it visible, and makes
* appear in the center of the screen. While also making it have a close operation
*/
JFrame frame = new JFrame("Button");
frame.setVisible(true);
frame.setSize(300, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
//Creates the panel, and adds it to the frame
JPanel panel = new JPanel();
frame.add(panel);
//Creates the label and adds it to the panel, also sets the text
JLabel label = new JLabel();
label.setText("Welcome" + "\n" + "\n");
panel.add(label);
//Creates the button and adds it to the panel
JButton button1 = new JButton("Button 1");
panel.add(button1);
}
}

1.If you want to use JFrame you have to extend your class to a subclass of JFrame:
public class frame extends JFrame {}
2.a)If you want to put Text in your Frame use JLabel and add it to your frame:
JLabel hello = new JLabel("Hello");
add(hello);
2.b)If you want a console output just call System.out.println() in the constructor
Here is a small example class:
import javax.swing.JFrame;
import javax.swing.JLabel;
public class Frame extends JFrame {
public static void main(String args[]) {
new Frame();
}
Frame() {
System.out.println("Hello");
JLabel hello = new JLabel("Hello");
add(hello);
this.setSize(100, 100);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
}
have a look to the oracle lessons... or any java book!

If that is the case, I don't want to get into GUI just yet. (Learning from a book) Can I convert my current project to a jar file and have it automatically open a command prompt window upon double click?

Memory/Concentration Game Problems

So, I have been working on a Java Memory/Concentration Game assignment. I've not gotten as far as I wanted, it's only half finished, but I did have the GUI mostly working... Until I tried to add radio buttons to my Frame. I think the problem might be because I changed a JFrame(CardButtonPanelFrame) into a JPanel. I'm trying to add 3 JPanels to a larger JPanel which I add to a JFrame. I'm just getting a small blank window popping up when I used to have all 52 cards pop up.
Basically when I work on projects things can get out of control in their complexity so I thought I'd come here to make sure I'm heading in the right direction.
Here's my main:
import javax.swing.*;
public class Project3{
public static void main(String[] args){
JFrame frame = new JFrame();
Grid game = new Grid();
frame.pack();
frame.add(game);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}
}
Then this is outermost JPanel I'd like to hold the radio buttons at the top, the cards in the middle, and eventually the score at the bottom.
import java.awt.*;
import javax.swing.*;
public class Grid extends JPanel{
public Grid(){
JPanel panel = new JPanel(); //construct a frame
CardButtonPanelFrame buttons = new CardButtonPanelFrame();
wtf choices = new wtf();
panel.setLayout(new GridLayout(3,1)); //that panel uses GridLayout
panel.add(choices);//add the panels to the Frame
panel.add(buttons);
//frame.add(scores);
add(panel);
setVisible(true);
}
}
This is the radiobuttons panel... named wtf because I had some compiling issues and experimented with changing the name. I've not even gotten to the stage of figuring out how to implement the different player amounts yet.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class wtf extends JPanel implements ActionListener {
static String zerostring = "Zero Player Game";
static String onestring = "One Player Game";
static String twostring = "Two Player Game";
public wtf() {
super(new BorderLayout());
//Create the radio buttons.
JRadioButton zeroButton = new JRadioButton(zerostring);
zeroButton.setMnemonic(KeyEvent.VK_C);
zeroButton.setActionCommand(zerostring);
JRadioButton oneButton = new JRadioButton(onestring);
oneButton.setMnemonic(KeyEvent.VK_B);
oneButton.setActionCommand(onestring);
oneButton.setSelected(true);
JRadioButton twoButton = new JRadioButton(twostring);
twoButton.setMnemonic(KeyEvent.VK_D);
twoButton.setActionCommand(twostring);
//Group the radio buttons.
ButtonGroup group = new ButtonGroup();
group.add(zeroButton);
group.add(oneButton);
group.add(twoButton);
//Register a listener for the radio buttons.
zeroButton.addActionListener(this);
oneButton.addActionListener(this);
twoButton.addActionListener(this);
//Put the radio buttons in a column in a panel.
JPanel radioPanel = new JPanel(new GridLayout(0, 1));
radioPanel.add(zeroButton);
radioPanel.add(oneButton);
radioPanel.add(twoButton);
add(radioPanel, BorderLayout.LINE_START);
setBorder(BorderFactory.createEmptyBorder(20,20,20,20));
}
/** Listens to the radio buttons. */
public void actionPerformed(ActionEvent e) {
//do something with e.getActionCommand()
}
}
So I have two more classes but I think the current problem is here and I'm afraid of making this a giant wall of code. I have more questions but I think I'll take it one at a time so I don't end up posting pages and pages of code that no one wants to read.

One problem you're doing is calling pack() on your JFrame before adding components. Don't do that, but instead add all components that you can first, then call pack(), then setVisible(true)

JPanel on a JPanel in a JFrame will not show

Hello
I'm an amateur trying to learn/improve my understanding of Java by writing a score card for archery. I ‘m trying to produce a GUI and so far have successfully produced on a JPanel a row of 18 labels of differing sizes and colours suitable for scoring a dozen.
I then tried to add five of these 'labels panels' to another panel to build up a grid and save having to create and add as many as 150 labels in some cases . No success so far as the original labels panels will not show up. All the panels are displayed on a JFrame
I've tried a number of different ways of getting the code to work, using the Java tutorial and googling the internet and studying similar problems on this site but I'm going round in circles. I must have missed something somewhere and hope that you may be able to help.
I'm using Java 6 and JGrasp v1.8.8_01 as an IDE
The following code for the labels panel has been cut down as much of it is repetitive.
import javax.swing.*;
import java.awt.*;
public class ArrowScoreLabels extends JPanel{
public JPanel createContentPane(){
JPanel panelForLabels = new JPanel();
panelForLabels.setLayout(null);
//Code creates 18 labels, sets the size, position, background colours, border and
//font and adds the labels to the’panelForLabels
JLabel scorelabel1;
scorelabel1 = new JLabel("",JLabel.CENTER);
scorelabel1.setBorder(BorderFactory.createLineBorder(Color.black));
scorelabel1.setFont(new Font("Arial", Font.ITALIC, 26));
scorelabel1.setLocation(0, 0);//first value differs for each label
scorelabel1.setSize(35, 35);
scorelabel1.setOpaque(true);
panelForLabels.add(scorelabel1);
panelForLabels.setOpaque(true);
return panelForLabels;
}
}
Running the following class shows the 18 labels on panel
import javax.swing.*;
import java.awt.*;
public class TestArrowScoreLabels {
private static void createAndShowArrowLabels() {
//Create and set up the window.
JFrame frame = new JFrame("To score one dozen");
//Create and set up the content pane.
ArrowScoreLabels asl = new ArrowScoreLabels();
frame.setContentPane(asl.createContentPane());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(676, 73);
frame.setVisible(true);
}
//Main method to show the GUI/
public static void main(String[] args) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
createAndShowArrowLabels();
}
});
}
}
The following code for the second panel is similar, compiles but only shows the second green JPanel and not the panel with the labels.
import javax.swing.*;
import java.awt.*;
public class FiveDozenScorePanel{
public JPanel createContentPane(){
//A bottom JPanel on which to place five dozenpanels.
JPanel fivedozenpanel = new JPanel();
fivedozenpanel.setLayout(null); //requires absolute spacing
fivedozenpanel.setSize(676,185);
fivedozenpanel.setBackground(Color.green);
//Label panels for five dozen
ArrowScoreLabels dozenscorepanel1, dozenscorepanel2,
dozenscorepanel3,dozenscorepanel4,dozenscorepanel5;
//Create the 5 dozenscorelabels.
dozenscorepanel1 = new ArrowScoreLabels();
dozenscorepanel1.setLocation(5,5);//y value changes for each panel
fivedozenpanel.add(dozenscorepanel1);//plus the other 4
fivedozenpanel.setOpaque(true);
return fivedozenpanel;
}
private static void createAndShowDozenPanels() {
JFrame frame = new JFrame("To score five dozen");
FiveDozenScorePanel fdsp = new FiveDozenScorePanel();
frame.setContentPane(fdsp.createContentPane());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Display the window
frame.setSize(700, 233);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
createAndShowDozenPanels();
}
});
}
}
I've also tried frame.getContentPane().add(fdsp); - frame.pack(); and read so much about paint methods that I'm totally confused.
I can get the ArrowScoreLabels image to appear directly onto a JFrame rather than a JPanel but only one of them and not five.
I would appreciate being pointed in the right direction. Thankyou for your time.
Update - 14th Dec 2010
I have managed to display the panelForLabels Jpanel on another Jpanel on a JFrame. This was done by adding the following code to the class ArrowScoreLabels. The original createContentPane() method was renamed createRowOne(). The panelForLabels was coloured red and the fivedozen panel yellow to ascertain which was showing. However I was only able to persuade the programme to display one row of labels despite a great deal of experimentation and research.
public static JPanel createContentPane(){
//Bottom panelto hold rows of labels
JPanel fivedozenscorepanel = new JPanel();
fivedozenscorepanel.setLayout(null);//requires absolute spacing
fivedozenscorepanel.setSize(660,180);
fivedozenscorepanel.setBackground(Color.yellow);
fivedozenscorepanel.add(createRowOne());
fivedozenscorepanel.setOpaque(true);
return fivedozenscorepanel;
}
The only way I displayed the 5 rows of 18 labels was to create all 90 in the ArrowScoreLabels class and then add them to one JPanel using absolute spacing and then to a JFrame.
I've taken note of pstantons advice - thankyou for that - and I'm looking into using the MigLayout Manager.

simple answer: use a layout manager. don't use absolute positioning.
just comment out all of your calls to setLocation and setLayout and swing will use the default FlowLayout.
for more control over the display, use a different layout manager.
also, if you use multiple panels you will have trouble aligning things in different panels unless they contain the same number of components which are exactly the same size so consider using one panel for all of the labels.
you can achieve just about any layout you need using MigLayout.
EDIT: in your example, there's no need for ArrowScoreLabels need to extend JPanel since you are doing the work in createContentPane to construct a separate JPanel. later in your code you call new ArrowScoreLabels() wich will just return a blank JPanel, instead you need to call new ArrowScoreLabels().createContentPane()
if you want ArrowScoreLabels to extend JPanel, implement public ArrowScoreLabels() ie the constructor instead of createContentPane.

I've the impression you don't set a size to your dozenscorepanel1. So, set a size :-)
Be careful with the layout null, because it's a pain ; you always forget something. Write your own, or use an existing one.