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();

Java JTextField window size

Im trying to display to the user some text:
JTextField warningComponent = new JTextField(VERY_LONG_TEXT_NOENTERS);
warningComponent.setEditable(false);
but the window size is changed according to the text size. I want to set the window to be 30 X 40 all the time regardless of the warning text length.
And i want the warning text to be adjusted to the window size (maybe the user will have to scroll to see the end)
How do i do it?
Maybe i should use other swing component?
I tried most of the methods in JTextField class.
Thanks.

I add it to JPanel
Then the default layout manager should be a FlowLayout which will respect the preferred size of the text field.
To give a suggestion for the preferred size of the text field you need to do:
JTextField warningComponent = new JTextField(VERY_LONG_TEXT_NOENTERS, 20);
The second parameter will give a suggestion on how to size the text field to make approximately 20 characters visible at one time. You will then need to use the arrow keys to see the remaining characters.

And i want the warning text to be adjusted to the window size
If you want the textfield to resize according to the frame size and not the frame size following the dimension of the textfield, you may make use of specific layout to achieve that:
Using BorderLayout:
class MainPanel extends JPanel{
private JTextField txt;
public MainPanel(){
setLayout(new BorderLayout());
setPreferredSize(new Dimension(30, 40));
txt = new JTextField();
txt.setHorizontalAlignment(JTextField.HORIZONTAL);
add(txt);
}
}
Runner class to run to codes:
class TextFieldRunner{
public static void main(String[] args){
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run(){
JFrame frame = new JFrame("Text Runner");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new MainPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}

You can try JScrollPane in your application, JScrollPane is scroll-able horizontally and vertically as you wish. And add JTextArea to JScrollPane. JTextField is not scroll-able.
Here is a small example:
JScrollPane scrollPane = new JScrollPane();
JTextArea textArea = new JTextArea();
scrollPane.add(textArea);
scrollPane.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
scrollPane.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
This is the values for the scroll policy:
VERTICAL_SCROLLBAR_AS_NEEDED
VERTICAL_SCROLLBAR_NEVER
VERTICAL_SCROLLBAR_ALWAYS
HORIZONTAL_SCROLLBAR_AS_NEEDED
HORIZONTAL_SCROLLBAR_NEVER
HORIZONTAL_SCROLLBAR_ALWAYS

JTextArea with JScrollPAne within Frame with null Layout

I'm trying to add this JTextArea with a JScrollPane (with vertical but not horizontal scrollbar) to my frame but the result is just a grey area with a scrollbar on the right... I'm probably doing something really dumb but i've done that same exact thing to a JPanel and it worked
public class Chats {
public static int height = 600;
public static int length = 400;
public static void init(String me, String you){
JFrame frame = new JFrame ("Chat");
frame.setSize(larguraframe, alturaframe);
frame.setLocation(620, 100);
frame.setResizable(false);
frame.setLayout(null);
frame.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
JTextArea chat = new JTextArea();
chat.setColumns(10);
chat.setLineWrap(true);
chat.setWrapStyleWord(true);
JScrollPane scrollpane = new JScrollPane(chat, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER;
scrollpane.setBounds(length/8 - 27, height/9 + 27, 350, 380);
chat.setPreferredSize(new Dimension(lenght-15, 7*height/8-27));
frame.add(chat);
frame.add(scrollpane);
frame.setVisible(true);
}
}
I don't mind changing my frame's Layout but i really want one that allows me to put stuff exactly where i want it. Thanks
EDIT
Okay it now shows on my frame but the TextArea is still not resizable. When i write something in it using a JTextfield and a JButton with a Listener that appends the JTextfield's text to the JTextArea and then sets the text in the JTextField to "" it only accepts up to a certain ammount of lines. After that it just looks the same.

I know that you've already "accepted" an answer, but I feel that I'd be remiss if I didn't give an answer that gave important points, ones that in the long run would allow you to create a better and more robust (i.e., a more easily debuggable, modifiable, and enhanceable) application.
Again,
Never set a JTextArea's preferredSize, as this will create a JTextArea whose size is inflexibly set that will not add additional lines when needed. Instead set the JTextArea's row and column properties.
While null layouts and setBounds() might seem to Swing newbies like the easiest and best way to create complex GUI's, the more Swing GUI'S you create the more serious difficulties you will run into when using them. They won't resize your components when the GUI resizes, they are a royal witch to enhance or maintain, they fail completely when placed in scrollpanes, they look gawd-awful when viewed on all platforms or screen resolutions that are different from the original one.
Better to use a JPanel, or more often multiple nested JPanels, each using its own layout manager that allow you to more simply create agile and powerful complex yet beautiful GUI's.
When using layout managers, you'll want to pack() your JFrame after adding all components so that all layout managers will do their jobs and layout components appropriately.
I've an example program below I show,
a title JLabel with large centered text
a JTextArea, called chatViewArea, of specified row and column size held within a JScrollPane and that is for viewing the chat. It is non-focusable so that the user cannot directly interact with it.
Another JTextArea, called textEntryArea, for entering text. You could use a simple JTextField for this and give it an ActionListener so that it responds to the enter key, however if you want a multi-lined text component that acts similar, you'll need to change the key bindings for the JTextArea's enter key. I've done that here so that the enter key "submits" the text held within the textEntryArea JTextArea, and the control-enter key combination acts the same as the enter key used to -- creating a new line.
The main JPanel uses simply a BorderLayout to allow placement of the title at the top, the chat view JTextArea in the center and the text entry JTextArea at the bottom. Note that if you needed to see more components, such as a JList showing other chatters, this can be done by nesting JPanels and using more layouts if need be.
For example:
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import javax.swing.*;
#SuppressWarnings("serial")
public class Chat2 extends JPanel {
private static final int ROWS = 25; // rows in the chat view JTextArea
private static final int COLS = 40; // columns in the chat view JTextArea
// and text entry area
private static final int ENTRY_ROWS = 4; // rows in the text entry JTextArea
private static final int BL_HGAP = 10; // horizontal gap for our
// BorderLayout
private static final int BL_VGAP = 5; // vertical gap for our BorderLayout
private static final int EB_GAP = 15; // gap for empty border that goes
// around entire app
private static final String TITLE_TEXT = "My Chat Application";
private static final float TITLE_POINTS = 32f; // size of the title jlabel
// text
private JTextArea chatViewArea = new JTextArea(ROWS, COLS);
private JTextArea textEntryArea = new JTextArea(ENTRY_ROWS, COLS);
public Chat2() {
// label to display the title in bold large text
JLabel titleLabel = new JLabel(TITLE_TEXT, SwingConstants.CENTER);
titleLabel.setFont(titleLabel.getFont().deriveFont(Font.BOLD, TITLE_POINTS));
// set up the chat view JTextArea to have word wrap
// and to not be focusable
chatViewArea.setWrapStyleWord(true);
chatViewArea.setLineWrap(true);
chatViewArea.setFocusable(false);
// add it to a JScrollPane, and give the scrollpane vertical scrollbars
JScrollPane viewScrollPane = new JScrollPane(chatViewArea);
viewScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
// set up the text entry JTextArea
textEntryArea.setWrapStyleWord(true);
textEntryArea.setLineWrap(true);
// key bindings so that control-enter will act as enter and the enter key will "submit"
// the user input to the chat window and the chat server
// will allow us to use a multilined text entry area if desired instead
// of a single lined JTextField
setEnterKeyBinding(textEntryArea);
JScrollPane entryScrollPane = new JScrollPane(textEntryArea);
entryScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
// add an empty border around entire application
setBorder(BorderFactory.createEmptyBorder(EB_GAP, EB_GAP, EB_GAP, EB_GAP));
// make the main layout a BorderLayout
setLayout(new BorderLayout(BL_HGAP, BL_VGAP));
// add our components to the GUI
add(titleLabel, BorderLayout.PAGE_START);
add(viewScrollPane, BorderLayout.CENTER);
add(entryScrollPane, BorderLayout.PAGE_END);
}
// Again, use key bindings so that control-enter JTextArea will act as enter key
// and the enter key will "submit" the user input to the chat window and the chat server.
// When ctrl-enter is pushed the Action originally bound to the enter key will be called
// and when enter is pushed a new Action, the EnterKeyAction, will be called
private void setEnterKeyBinding(JTextArea textArea) {
int condition = JComponent.WHEN_FOCUSED; // only for focused entry key
InputMap inputMap = textArea.getInputMap(condition);
ActionMap actionMap = textArea.getActionMap();
KeyStroke entryKeyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, 0);
KeyStroke ctrlEntryKeyStroke = KeyStroke.getKeyStroke(KeyEvent.VK_ENTER, KeyEvent.CTRL_DOWN_MASK);
// first give ctrl-enter the action held by enter
Object entryKey = inputMap.get(entryKeyStroke);
Action entryAction = actionMap.get(entryKey);
inputMap.put(ctrlEntryKeyStroke, ctrlEntryKeyStroke.toString());
actionMap.put(ctrlEntryKeyStroke.toString(), entryAction);
// now give enter key a new Action
EnterKeyAction enterKeyAction = new EnterKeyAction();
inputMap.put(entryKeyStroke, entryKeyStroke.toString());
actionMap.put(entryKeyStroke.toString(), enterKeyAction);
}
public void appendToChatArea(final String text) {
if (SwingUtilities.isEventDispatchThread()) {
chatViewArea.append(text + "\n");
} else {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
chatViewArea.append(text + "\n");
}
});
}
}
private class EnterKeyAction extends AbstractAction {
#Override
public void actionPerformed(ActionEvent e) {
String text = textEntryArea.getText();
textEntryArea.setText("");
chatViewArea.append("User: " + text + "\n");
// TODO send text to the chat server!
}
}
private static void createAndShowGui() {
Chat2 mainPanel = new Chat2();
JFrame frame = new JFrame("My Chat Window");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
// pack the JFrame so that it will size itself to its components
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

Try setting a layout like this:
frame.setLayout(new BorderLayout());
And adding the scrollpane to the center:
frame.add(scrollpane, BorderLayout.CENTER);
Also remove the line pointed by Jire in his answer.

You don't need to add chat because it is adapted by scrollPane.
Remove this line: frame.add(chat);

Add
chat.setBounds(length/8 - 27, height/9 + 27, 330, 360);
And see the magic happen... but do tweek the arguments here in order to get the right dimensions.
For resizable frame just do frame.setResizable(true); instead of frame.setResizable(false);

Non-clickable text displayed on file menu

I am trying to get some text to display to the menu bar at the top of my application (the empty white space at the end of the row). I could add it as a JMenu with no JMenuItems, I suppose, but I'd really prefer to have it non-clickable. Does anyone know where to start looking to accomplish this? If it isn't possible, is there any way to add a JMenu to the end of the row?
Thanks

Does anyone know where to start looking to accomplish this?
Yes, you would control the positioning with an appropriate LayoutManager, and as #MadProgrammer suggested, probably just add a JLabel to your JMenuBar.
Here is a minimal working example. It might not be exactly what you're looking for, but it does show you where to start looking.
import java.awt.*;
import javax.swing.*;
public class Example {
public static void main(String args[]) {
JFrame frame = new JFrame();
JMenuBar menubar = new JMenuBar();
JLabel label = new JLabel("Hello World");
menubar.setLayout(new BorderLayout());
menubar.add(label, BorderLayout.EAST);
frame.setLayout(new BorderLayout());
frame.add(menubar, BorderLayout.PAGE_START);
frame.setMinimumSize(new Dimension(200, 100));
frame.setVisible(true);
}
}

JScrollBar Vertical/Horizontal setting problem- Java Swing

I am just trying to add a vertical scroll bar to my TextField and TextArea.
I am using a ScrollPane and it should create avertical/horizontal scroll bar by default.
Problem:
I need a vertical scroll bar to see the data which is not visible.
In the start a vertical scrollbar appears but when the data increases the vertical scrollbar changes to a horizontal scroll bar.
Also the TextField disappears and only a horizontal scrollbar appears in its place.
I guess it is because how I have set the bounds but I tried changing the bounds and it ends up completely doing away with the TextField.
My code snippet:
public JTextField inputField = new JTextField();
public JTextArea talkArea = new JTextArea();
public JScrollPane inputFieldScroll = new JScrollPane(inputField);
public JScrollPane talkAreaScroll = new JScrollPane(talkArea);
talkArea.setEditable(false);
talkArea.setBackground(Color.white);
talkAreaScroll.setBounds(new Rectangle(TALK_LEFT, TALK_TOP, TALK_WIDTH, TALK_HEIGHT));
this.getContentPane().add(talkAreaScroll, null);
//set input area
inputField.setBackground(Color.white);
inputField.setBounds(new Rectangle(INPUT_LEFT, INPUT_TOP, INPUT_WIDTH, INPUT_HEIGHT));
inputFieldScroll.setVerticalScrollBar(new JScrollBar());
inputFieldScroll.setBounds(new Rectangle(INPUT_LEFT, INPUT_TOP, INPUT_WIDTH, INPUT_HEIGHT));
Question:
Is there some parameter I need to set so that it remains a vertical scroll bar?
Why does the input scroll bar occupy the whole inputfield when the data becomes a huge line? It appears as a proper vertical scrollbar in the start.
Any advice appreciated.
Thanks

Below is a small compilable code snippet I mentioned above. I agree with camickr that you should not be using absolute positioning but rather use the layout managers. If you absolutely need to have a horizontal scrollbar for the JTextField, then one way to get it to work is to have it show up always, using the JScrollPane constructor that allows for this. i.e,
JScrollPane inputPane = new JScrollPane(inputField, JScrollPane.VERTICAL_SCROLLBAR_NEVER,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
For e.g.,
import java.awt.*;
import javax.swing.*;
public class FuSwing1b extends JPanel {
private static final int TA_ROWS = 25;
private static final int TA_COLS = 60;
private JTextField inputField = new JTextField();
private JTextArea talkArea = new JTextArea(TA_ROWS, TA_COLS);
public FuSwing1b() {
talkArea.setEditable(false);
talkArea.setFocusable(false);
talkArea.setBackground(Color.white);
//talkArea.setPreferredSize(new Dimension(TALK_WIDTH, TALK_HEIGHT));
JScrollPane talkPane = new JScrollPane(talkArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
JScrollPane inputPane = new JScrollPane(inputField, JScrollPane.VERTICAL_SCROLLBAR_NEVER,
JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
int gap = 10;
setLayout(new BorderLayout(gap, gap));
add(talkPane, BorderLayout.CENTER);
add(inputPane, BorderLayout.SOUTH);
setBorder(BorderFactory.createEmptyBorder(gap , gap, gap, gap));
}
private static void createAndShowUI() {
JFrame frame = new JFrame("FuSwing1b");
frame.getContentPane().add(new FuSwing1b());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowUI();
}
});
}
}

Don't play with the bounds. Use a layout manager and you won't have to worry about this.
When you create the text field use something like:
JTextField textField = new JTextField(10);
This will create a text field that will hold a minimum of 10 characters. If the number of characters exceeds the display width of the text field the use can see the remaining characters by using the right/left arrow keys. That is the normal UI used by all applications I have ever seen. Don't try to create your own UI by using a horizontal scrollbar. Users are not accustomed to that.
for the text area you can create it using:
JTextArea textArea = new JTextArea(5, 30);
JScrollPane scrollPane = new JScrollPane( textArea );
to create a text area with 5 rows and approximately 30 character per row.
Now add the text field and the scrollpane to your frame "using layout managers" and then pack the frame. The layout managers will determine the best size for the compoents. Scrollbars will automatically appear on the text area as you add text to it and the text exceeds 5 lines.