First, I know how to add a scrollbar in a JTextArea.
JTextArea textarea = new JTextArea();
JScrollPane scrollbar = new JScrollPane(textarea);
But in the following JTextArea class code below
public class MyTextArea extends JTextArea
{
public MyTextArea()
{
setEditable(true);
setSize(500, 500);
//JScrollPane scroll = new JScrollPane(this);
// ...
}
}
How do I add a scroll bar? I tried using JScrollPane, but it didn't work. I tried making a new method, but it didn't work either.
This is my JFrame class.
public class MyFrame extends JFrame
{
MyFrame()
{
setLayout(null);
setTitle("Frame Title");
setSize(600, 600);
MyTextArea mytextarea = new MyTextArea();
add(mytextarea);
setVisible(true);
setDefaultCloseOperation(MyFrame.EXIT_ON_CLOSE);
}
}
And my main.
public static void main(String[] args)
{
new MyFrame();
}
Simply by wrapping the JTextArea in a JScrollPane...
add(new JScrollPane(mytextarea));
will show the scrollbars when the component's content is larger then the scroll panes viewable area
The question you really need to ask is, why are you extending JTextArea? Have a look at Prefer composition over inheritance more details
In the example that you've posted, you're not adding "a scrollbar in a JTextArea" you're adding the JTextArea to a JScrollPanel
Also, if you're not actually extending a class (adding new functionality to it) is better to create instance of that class and modify them instead, but, if you're set on doing that, you can do something like this:
public class MyTextArea extends JScrollPanel{
public JTextArea ta = new JTextArea();
public MyTextArea(){
ta.setEditable(true);
ta.setSize(500, 500);
setViewPortView(ta);
}
}
Related
I have a JFrame which contains 3 JPanels (each in a separate class). The first JPanel contains two JTextFields in which I write the name of the file to be read from and the condition to be fulfilled respectively. This doesn't really affect my question, so let's move on.
The second JPanel has a JTextArea.
The third JPanel has two JButtons (Load, Sort) which are supposed to load a list of entries that suffice the condition from the first JPanel and then reorganize them according to some rules (respectively).
THE PROBLEM:
Ok so, the first class is the JFrame class in which i just do the standard look and feel of the window.
The second class is the first JPanel with two JTextFields.
I won't give code for this one because the second JPanel code is shorter and has the same problem so I imagine that the same solution would apply.
Third class contains the JTextArea in which I should display certain entries from the text-file.
Code:
public class SecondPanel extends JPanel {
JPanel panel;
JTextArea lista;
public SecondPanel() {
panel = new JPanel();
list = new JTextArea("List");
list.setPreferredSize(new Dimension(200, 150));
this.add(list);
}
}
Moving on, the fourth class contains the Jbuttons and the ActionListener(Button listener). Ok so here is the part of the code from the button listener class
CODE:
private class ButtonListener implements ActionListener {
SecondPanel secondPanel = new SecondPanel();
FirstPanel firstPanel = new FirstPanel();
#Override
public void actionPerformed(ActionEvent e) {
if(e.getActionCommand().equals("Load")) {
//calls method that loads data from the text in a firstPanel field
loadData(firstPanel.theFile.getText());
for(int i = 0; i< students.length; i++) {
if(students[i]!=null) {
// doesn't write anything tried with .setText etc.
secondPanel.list.append(students[i]+"\n");
}
}
}
}
}
So the program won't get text when i type in the JTextField designated for the file path. And when i do it manually in the code, It won't write the changes to the list on the Window (JTextArea). But when i System.out.print to the console it prints the changes and lists entries correctly as well as any setText changes I make. It just won't write or read to and from the Window..
What should I do?
The problem is that you are calling your setText methods on the wrong objects.
In your listener class, you declared two new panels as class variables, and then you call your methods on them, but i think those panels are not the ones you really want to change.
You should first add your panels to your Jframe object, and refer to them on your ActionListener.
Here i provide you a minimal code which modifies a JTextArea when a JButton is pressed. (same for a JTextField)
import java.awt.*;
import javax.swing.*;
public class MyJFrame extends JFrame {
SecondPanel sPanel;
public MyJFrame() {
super("main");
Container c = getContentPane();
c.setLayout(new BorderLayout());
JButton button = new JButton("load");
button.addActionListener(new LoadListener());
c.add(sPanel = new SecondPanel(), BorderLayout.NORTH);
c.add(button, BorderLayout.SOUTH);
pack();
setVisible(true);
}
class SecondPanel extends JPanel {
public JTextArea list;
public SecondPanel() {
super();
list = new JTextArea("List");
list.setPreferredSize(new Dimension(200, 150));
add(list);
}
}
class LoadListener implements ActionListener {
#Override
public void actionPerformed(ActionEvent e) {
sPanel.list.setText("new text for the jtext area");
}
}
public static void main(String[] args) {
new MyJFrame();
}
}
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
I am new to Java; but I'm having a blast. I feel like I'm missing something really simple; but I can't figure it out.
I want the RadioButtons to be displayed inside the JFrame."
public class HelloWorldFrame extends JFrame
{
private TitledBorder title;
public HelloWorldFrame()
{
super("Hello World! ");
JFrame helloWorld = new JFrame();
JLabel label = new JLabel();
title = BorderFactory.createTitledBorder("Language");
title.setTitleJustification(TitledBorder.LEFT);
label.setBorder(title);
add(label);
setSize(300, 200);
JRadioButton button1 = new JRadioButton("English");
JRadioButton button2 = new JRadioButton("French");
JRadioButton button3 = new JRadioButton("Spanish");
ButtonGroup bG = new ButtonGroup();
bG.add(button1);
bG.add(button2);
bG.add(button3);
label.add(button1);
label.add(button2);
label.add(button3);
helloWorld.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
//The main class starts here
public class HelloWorldApp
{
public static void main(String[] args)
{
JFrame helloWorld = new HelloWorldFrame();
helloWorld.setVisible(true);
}
}
The first question is why? Why do you want to add the radio buttons to a JLabel?
Having said that, you can set the labels layout manager to something other then it's default value of null...
label.setLayout(new FlowLayout());
label.add(button1);
label.add(button2);
label.add(button3);
Next...your class extends from JFrame, but in your constructor, you are creating another JFrame, this means that when you do...
JFrame helloWorld = new HelloWorldFrame();
helloWorld.setVisible(true);
Nothing will be displayed, because nothing has been added to the frame.
Instead, make your class extend from something like JFrame and then add that to your JFrame in main
Updated
I just did some testing and doing this (adding buttons to a label) won't work well, as the JLabel calculates it's preferred size based on the text and icon, not it's contents (like something like JPanel would)...just saying...
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 need to write a simple tennis game.
To move between different windows(panel with main menu, panel with game, panel with settings) I decided to use inner classes extends JPanel and replace it when some events like start new game occurs.
but the problem is - it doesn't see my inner class. I mean I add it to JFrame
mainframe.add(new MainMenuPanel());
but there is nothing on the screen when I run program. What's the problem?
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class MainFrame{
JFrame mainframe;
public static void main(String[] args){
new MainFrame();
}
public MainFrame() {
mainframe = new JFrame();
mainframe.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
mainframe.setSize(300, 400);
mainframe.setTitle("X-Tennis v0.1");
mainframe.add(new MainMenuPanel());
mainframe.getContentPane().setLayout(new GridLayout());
mainframe.getContentPane().setBackground(Color.WHITE);
mainframe.setVisible(true);
}
public class MainMenuPanel extends JPanel {
JPanel mainmenupanel;
JLabel label1;
JButton btnNewGame,btnJoinGame;
ImageIcon iconNewGame,iconJoinGame;
public MainMenuPanel(){
mainmenupanel = new JPanel();
label1 = new JLabel("X-TENNIS");
label1.setFont(new Font("Comic Sans MS",Font.ITALIC,20));
label1.setForeground(Color.BLUE);
btnNewGame = new JButton("New Game", iconNewGame);
btnNewGame.setFocusPainted(false);
btnNewGame.addActionListener(
new ActionListener() {
public void actionPerformed(ActionEvent e){
JOptionPane.showMessageDialog(mainframe, "New game");
//delete current panel and add another to mainframe
}
}
);
btnNewGame.setPreferredSize(new Dimension(140,30));
btnJoinGame = new JButton("Join game",iconJoinGame);
mainmenupanel.add(label1);
mainmenupanel.add(btnNewGame);
}
}
}
There is no need for mainmenupanel within the MainMenuPanel class as MainMenuPanel is a JPanel itself
Simple add all the components in MainMenuPanel directly to itself
You create a new JPanel, mainmenupanel, inside MainMenuPanel but never add that to the container itself. You could do
add(mainmenupanel);
If you intend for this JPanel to occupy the full area of the parent, then you can simply add your components directly to your instance of MainMenuPanel as indicated by #Mad
First you should add your component to the ContentPane. In Swing, all the non-menu components displayed by the JFrame should be in the ContentPane.
mainframe.getContentPane().add(new MainMenuPanel());
Edit: I was wrong about the content pane, see #MadProgrammer comment.
Then you have to add the JPanel that you create in MainMenuPanel to the MainMenuPanel instance itself.
add(mainmenupanel);
But you should probably get rid of that intermediary container itself and add your labels to the MainMenuPanel instance itself:
add(label1);
add(btnNewGame);
mainmenupanel.add(label1);
mainmenupanel.add(btnNewGame);
try this :
super.add(label1);
super.add(btnNewGame);