Anyone help me how to add a scroll bar to a JTextArea with Swing in Java?
The JTextArea just disappear when I add the scroll bar on it.
Hope somebody get me add a vertical scrollbar on it.
Additional explanation will be very thankful
public class Practice extends JFrame {
JFrame frame = new JFrame("AAA");
JTextArea textarea = new JTextArea();
JScrollPane scroll = new JScrollPane(textarea);
JPanel panelForScroll = new JPanel(null);
public Practice(){
frame.setLayout(null);
frame.setBounds(100,100,400,710);
frame.setResizable(false);
frame.setVisible(true);
textarea.setEditable(false);
textarea.setFont(new Font("arian", Font.BOLD, 16));
textarea.setBounds(20, 280, 340, 70);
panelForScroll.add(scroll);
frame.add(panelForScroll); //can't find text area....
}
public static void main(String[] args) {
new Practice();
}
}
There are several errors in your code:
You're using a null layout, this is discouraged as it produces more problems than solutions, specially when you try to use JScrollPanes, since they take the preferredSize of the Component to decide whether to add the scroll bars or not. See Why is it frowned upon to use a null layout in Swing? for more information about this. To fix this, remove this line:
frame.setLayout(null);
And instead use a layout manager or combinations of them along with borders for extra spacing between components.
While null layouts might seem like the best, easiest and faster way to design complex GUIs for Swing newbies, the more you progress in it, the more problems related to the use of them you'll find (as it's the case)
You're extending your class from JFrame and you're creating an instance of JFrame in it too, please use one or the other. When you extend JFrame you're saying your class is a JFrame and thus it cannot be placed inside another Container because JFrame is a rigid container. I recommend to forget the extends JFrame part, since anyway you're not using the JFrame that is generated by this action and stay with the object you created. See https://stackoverflow.com/questions/41252329/java-swing-using-extends-jframe-vs-calling-it-inside-of-class for a more detailed answer about this problem.
You're making your GUI visible before you have added all the elements, this could cause your GUI to not display all the elements until you hover over them, this line:
frame.setVisible(true);
Should be one of the last lines in your program
You're not placing your program on the Event Dispatch Thread (EDT) which makes your application to not be thread safe, you can fix it by writing this on your main method.
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
//Place your constructor here
}
});
You're setting bounds for the textArea but not for the scrollPane, but you should really not be setting the bounds manually (see point #1 again).
Now, you can make a simple GUI with a JTextArea with a JScrollPane as follows:
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class ScrollPaneToTextArea {
private JTextArea textArea;
private JFrame frame;
private JScrollPane scroll;
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new ScrollPaneToTextArea().createAndShowGui();
}
});
}
public void createAndShowGui() {
frame = new JFrame("ScrollPane to TextArea");
textArea = new JTextArea(10, 20); //Rows and cols to be displayed
scroll = new JScrollPane(textArea);
// scroll = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
frame.add(scroll); //We add the scroll, since the scroll already contains the textArea
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
Which produces this output and the scroll bars are added when needed (i.e. when text goes further than the rows it can handle in the view)
If you want the vertical scroll bars to appear always you can uncomment the line:
scroll = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
Which will produce the following outputs:
You can read more about JScrollPane in the docs and JTextArea also in their own docs.
JPanel panelForScroll = new JPanel(null);
This sets the NULL Layout to this JPanel. This would require more configuration (just as you did for the frame object).
Just remove the null (also from frame.setLayout(null)!)
You have to use Jtextpane to get the scroll bar on textarea.
JTextArea ta = new JTextArea();
JScrollPane sp = new JScrollPane(ta);
JFrame f = new JFrame();
f.getContentPane().add(sp);
you are setting the panel's layout to null,then you didn't specify the scroll bar bounds. Since you only have one component in your panel which is the scroll bar I recommend using FlowLayout
Related
I am trying to make a simple text editor using JTextArea, but when I type more text so that it goes off the screen, the JScrollPane is still not enabled and not letting me to scroll. I've looked for hours for answers on the internet but nothing seemed to help me.
Here is my code:
import mods.JFrame.JFrameMods;
import javax.swing.*;
public class NimbleIDE {
JFrame frame;
JTextArea main;
JScrollPane scroll = new JScrollPane(main);
NimbleIDE() {
frame = new JFrame();
main = new JTextArea();
frame.add(main);
//Frame setting up
initialiseBlankJFrame(frame, "NimbleIDE");
frame.add(scroll);
//Text setting up
main.setSize(JFrameMods.getScreenWidth() - 14, JFrameMods.getScreenHeight()); //JFrameMods is a custom class I made previously
main.setWrapStyleWord(true);
main.setLineWrap(true);
main.setEditable(true);
//Scroll setting up
scroll.setBounds(JFrameMods.getScreenWidth() - 14, 0, 16, JFrameMods.getScreenHeight() - 23);
scroll.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
}
initialiseBlankJFrame(JFrame frame, String title) {
frame.setVisible(true);
frame.setExtendedState(MAXIMIZED_BOTH);
frame.setLayout(null);
frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
frame.getContentPane().setBackground(Color.white);
frame.setTitle(title);
}
}
This:
JTextArea main;
JScrollPane scroll = new JScrollPane(main);
effectively means this:
JScrollPane scroll = new JScrollPane(null);
You're passing a null object to the JScrollPane.
You can fix your problem by passing an actual JTextArea object to your scroll pane. Also note that the scroll pane is the only component that you explicity have to add to your JFrame. Something like this:
public class NimbleIDE {
JFrame frame;
JTextArea main;
JScrollPane scroll;
NimbleIDE() {
frame = new JFrame();
main = new JTextArea();
scroll = new JScrollPane(main);
//Frame setting up
initialiseBlankJFrame(frame, "NimbleIDE");
frame.add(scroll);
// ...
}
// ...
}
You may also want to take a look at the following Java Trails:
How to Use Scroll Panes (The Java™ Tutorials > Creating a GUI With Swing > Using Swing Components)
Doing Without a Layout Manager (Absolute Positioning) (The Java™ Tutorials > Creating a GUI With Swing > Laying Out Components Within a Container)
I am almost certain this question was asked before here: Java Swing: How to change GUI dynamically , but I seem to just have some fundamental misunderstanding in how it works.
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;
public class JTest extends JFrame
{
public static void main(String[] args)
{
JTest t = new JTest();
}
Container pane;
public JTest()
{
setSize(500,500);
setTitle("JTest");
setDefaultCloseOperation(EXIT_ON_CLOSE);
pane = getContentPane();
pane.setLayout(new GridLayout(1,2));
JButton old = new JButton("old");
old.addActionListener(new OldButton());
pane.add(old);
JScrollPane scroll = new JScrollPane(new JTextArea(50,20));
pane.add(scroll);
setVisible(true);
}
private class OldButton implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
pane.setLayout(new GridLayout(1,2));
JButton old = new JButton("new");
old.addActionListener(new NewButton());
pane.add(old);
JScrollPane scroll = new JScrollPane(new JTextArea(50,20));
pane.add(scroll);
pane.validate();
}
}
private class NewButton implements ActionListener
{
public void actionPerformed(ActionEvent e)
{
pane.setLayout(new GridLayout(1,2));
JButton old = new JButton("old");
old.addActionListener(new OldButton());
pane.add(old);
JScrollPane scroll = new JScrollPane(new JTextArea(50,20));
pane.add(scroll);
pane.validate();
}
}
}
This code should replace the preexisting layout with a new one anytime the button in the corner is pressed, but instead, it just adds the new layout to the frame. Can someone tell me what I'm doing wrong?
EDIT:
Adding some information. A picture for reference:
I'm making a set of components like this inside the scroll pane. whenever I press the "Make new field" button, I want it to add a "field" (the name of the field followed by a textarea or some such) to the set in that scrollpane. This means changing the layout of the area inside the scrollpane to include the new field.
OK -- so it looks like what you want to do (and please correct me if I'm wrong) is to add a new component to a JPanel that is displayed within a JScrollPane. If so, then you do not want to change or swap layouts, and you certainly don't want to keep adding new JScrollPanes. Instead consider doing:
Create one JScrollPane and add to your GUI. Don't re-add this as you'll only need one.
add a JPanel to the JScrollPane's viewport that uses a layout that allows multiple components to be easily added to it. Perhaps a GridLayout or a BoxLayout, depending on what you need.
Also consider not adding the above JPanel directly to the viewport but rather adding it to another JPanel, one that uses BorderLayout, adding the first JPanel to the BorderLayout-using JPanel's BorderLayout.PAGE_START position, and then add this to the JScrollPane's viewport. This way the first JPanel won't stretch to fill the viewport initially.
Then in your button's ActionListener, add your components to the first JPanel by calling .add(...) on it, and then call revalidate() and repaint() on that first JPanel to layout the newly added components and repaint the JPanel and its contents.
Ok, so it turns out this wasn't a layout problem at all. I had failed to realize that setting a new layout doesn't cause the previous layout's components to disappear, you have to remove them before adding the new components. That's why I was getting duplication.
Thanks for pointing me in the right direction, though.
I am trying to use Java Swing to create a simple GUI in which I have a drawing pad and some buttons it all works fine until I add this code for the JTextField:
String text = "hello";
JTextArea textArea = new JTextArea(text);
textArea.setPreferredSize(new Dimension(500, 50));
textArea.setEditable(false);
Before adding this code the drawpad displays on the left of the screen followed by the buttons, when I add this only the drawpad is displayed unless I resize the frame in which case the buttons and text field reappear although the text field is hidden behind the drawpad slightly. Here is the full code:
public class testGUI extends Frame{
public static void main(String[] args) {
JFrame frame = new JFrame("Neural Networks");
frame.setSize(700, 300); //set the size of the frame
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true); //make it visible
Container content = frame.getContentPane();
content.setLayout(new BorderLayout());
JPanel mainPanel = new JPanel();
final PadDraw drawPad = new PadDraw();
drawPad.setSize(100, 100);
content.add(drawPad);
JButton clearButton = new JButton("Clear");
clearButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
drawPad.clear();
}
});
JButton loadButton = new JButton("Load");
loadButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
//Load something here
}
});
JButton testButton = new JButton("Test Draw Pad Image");
testButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
//
}
});
JButton loadImage = new JButton("Test image from file");
loadImage.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
//String filename = textField.getText();
}
});
String text = "hello";
JTextArea textArea = new JTextArea(text);
textArea.setPreferredSize(new Dimension(500, 50));
textArea.setEditable(false);
mainPanel.add(clearButton);
mainPanel.add(loadButton);
mainPanel.add(testButton);
mainPanel.add(loadImage);
mainPanel.add(textArea);
content.add(mainPanel);
}
}
You're adding the drawPad and the mainPanel to the content panel, which uses BorderLayout, without specifying any location. They thus end up both in the center position of the border layout, which is supposed to contain only one component.
See How to use BorderLayout in the Swing tutorial.
Also note that setting the preferred size is not something you should do. Instead, the preferred size is supposed to be automatically computed based on other sttings (the contained components, the number of rows and columns of a text area, etc.)
And a JTextArea should be enclosed into a JScrollPane to be good-looking and allow you to scroll.
JPanel mainPanel = new JPanel();
The default layout for a JPanel is a FlowLayout, so all the components flow on a single row. If there is not enough room on the row then the components wrap to the next row.
So when you add the JTextArea the flow is disturbed. The solution is to use a combination of layout managers to get your desired layout effect. Read the section from the Swing tutorial on Using Layout Managers for more information and examples.
JTextArea textArea = new JTextArea(text);
textArea.setPreferredSize(new Dimension(500, 50));
Also, you should NOT set the preferred size of the text area (or any Swing component for that matter). Instead you should do something like:
JTextArea textArea = new JTextArea(rows, columns);
and let the component determine its own preferred size. Also a text area is typically used with a JScrollPane and then you add the scroll pane to your panel:
JScrollPane scrollPane = new JScrollPane( textArea );
Edit:
Taking a second look at your code you have many more problems.
The point of using a layout manager is to have the layout manager set the size and location of the components. So your code should not have any logic related to the size/location of a component.
When you use the add(...) statement on a BorderLayout without a constraint, the component gets added to the CENTER. However only the last component added is managed by the BorderLayout. So only the "mainPanel" is given a size/location by the layout manager. That is why you need the setSize(...) statement on the drawPad to make the component visible. Although you now have the problem that two components are painted in the same space.
So to see the drawPad on the left you might want to use:
content.add(drawPad.BorderLayout.LINE_START);
However this still probably won't work because I'm guessing you are doing custom painting on the draw pad which means you will also need to override the getPreferredSize() method of the class so the layout manager can use the information to determine the size of the component. Read the section from the Swing tutorial on Custom Painting for more information and working examples.
Finally some other issues:.
The setVisible(...) statement should be invoked AFTER all the components have been added to the frame.
To follow Java standards, class names should start with an upper case character.
You should NOT be extending "Frame". There is no need to extend any class in your example.
Read the tutorial and download the demos for examples of better structured code.
I think im heading in the wrong direction. Im creating a notepad app. I have every method running perfectly except one - WordWrap
Its just a JTextarea inside a panel inside a frame.
I think i should be using a JScrollPane instead of a Textarea? Or aswell as it even?
How would i go about resizing the width of a textarea or am i correct in saying i need to insert a JScrollPane.
Edit
Ok so my attempt is gone wrong somehow. Text area doesnt work. Something possibly needs resizing.
public class TextEditor extends JFrame implements ActionListener{
JFrame textFrame = new JFrame();
JPanel textPanel = new JPanel();
JTextField textArea = new JTextField();
JScrollPane scroll = new JScrollPane(textArea);
JTextArea text = new JTextArea(24,33);
public TextEditor(String str){
super(str);
textFrame.setDefaultCloseOperation(EXIT_ON_CLOSE);
textFrame.add(textPanel);
textPanel=(JPanel)getContentPane();
textPanel.setLayout(new FlowLayout());
textPanel.setBackground(Color.WHITE);
// Create text Area
textPanel.add(scroll);
scroll.add(text);
textPanel.setFont(textAreaFont);
textArea.setFont(textAreaFont);
text.setFont(textAreaFont);
}
public static void main(String args[])
{
TextEditor notePad = new TextEditor("Notepad");
notePad.setSize(500,500);
notePad.setVisible(true);
notePad.setDefaultCloseOperation(EXIT_ON_CLOSE);
}
Have a look at what I have tried to put together:
public class SO{
public static void main(String[] args) {
JFrame f = new JFrame();
JPanel p = new JPanel();
JTextArea outputArea = new JTextArea();
outputArea.setColumns(20);
outputArea.setRows(20);
outputArea.setLineWrap(true); //Set line wrap
outputArea.setWrapStyleWord(true); //set word wrap
JScrollPane sp = new JScrollPane(outputArea); //Create new scroll pane with textarea inside
p.add(sp); //add scrollPane to panel
f.add(p); //Add panel to frame
f.pack()
f.setLocationRelativeTo(null); //frame location
f.setVisible(true);
}
}
The scroll pane is created using the textarea in the constructor, this seems to allow the scroll pane to 'contain' the JTextArea, adding scroll bars when the text the area contains exceeds the limits. Earlier when creating the JTextArea I set two lines of code to set a word wrap on it, this stops words seeping off the sides by pushing them onto the next line. Have a look and see if it can help with your project.
Good Luck!
import java.awt.*;
import javax.swing.*;
public class TextEditor extends JFrame {
JFrame textFrame = new JFrame();
JPanel textPanel = new JPanel();
JTextArea textArea = new JTextArea(10,25);
public TextEditor(String str){
super(str);
textFrame.setDefaultCloseOperation(DISPOSE_ON_CLOSE); // nicer
add(textPanel);
textPanel.setLayout(new GridLayout());
textPanel.setBackground(Color.WHITE);
// Create text Area
JScrollPane scroll = new JScrollPane(textArea);
textPanel.add(scroll);
}
public static void main(String args[])
{
TextEditor notePad = new TextEditor("Notepad");
notePad.setVisible(true);
notePad.setDefaultCloseOperation(EXIT_ON_CLOSE);
notePad.pack();
}
}
There were so many things wrong in that short code that I lost track of the changes. Two things I can recall are:
The code was quite confused about what was a JTextField and what was a JTextArea.
It added strange things to other strange things for no apparent reason.
I am developing a small desktop application in NetBeans. On my UI, I place a JPanel and put a single JLabel on it. The content of this JLabel is generated dynamically, so if the content is very large then it goes out of screen.So is there any way in which I can specify a fixed size for the JPanel and of course ScrollBars should appear when the text exceeds the screen size.
You will have to just pass Component reference to the JScrollPane Constructor.
It will work fine. You can definetely use JScrollPane
The following is the sudo example of the JScrollPane for JPanel from my past project. Hope it will be useful for you.
import javax.swing.*;
import java.awt.*;
public class Frame01
{
public static void main(String[] args){
SwingUtilities.invokeLater (new Runnable ()
{
public void run ()
{
JFrame frame = new JFrame("panel demo");
frame.setDefaultCloseOperation (JFrame.DISPOSE_ON_CLOSE);
JPanel panel = new JPanel();
Container c = frame.getContentPane();
panel.setSize(100,100);
panel.setLayout(new GridLayout(1000,1));
for(int i = 0; i<1000;i++)
panel.add(new JLabel("JLabel "+i));
JScrollPane jsp = new JScrollPane(panel);
c.add(jsp);
frame.setSize(100,100);
frame.setVisible(true);
}
});
}
}
Use JScrollPane to contain Your big JPanel.
so in case when the contents are very large it goes out of screen, maybe you have to look for TextComponents as JTextArea or JEditorPane, tutorial contains example including basic usage for JScrollPane
In the Navigator, click on JPanel with the right mouse button --> Enclose In --> Scroll Pane.
Done!, You have now scrolls