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How to make button in one class affect text area in another?

Please help me to understand how this works. I'm having difficulties to understand how, for example, JButton in one class can alter text in JTextArea that is in another class of a same package. I've made a simple app just to ask a question here, I need this for a bigger school project where I need to implement this to work with multiple classes.
When I put everything in the same class it works but I need it in separate classes.
Here is the simple code.
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class Button extends JPanel {
private JButton button;
private Panel panel;
public Button() {
button = new JButton("BUTTON");
panel = new Panel();
add(button);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JButton clicked = (JButton) e.getSource();
String input = clicked.getText();
panel.setTextArea(input);
//System.out.println(input);
}
});
}
}
class Panel extends JPanel {
private JTextArea textArea;
public Panel() {
setLayout(new BorderLayout());
textArea = new JTextArea();
add(textArea, BorderLayout.CENTER);
}
public JTextArea getTextArea() {
return textArea;
}
void setTextArea(String text) {
this.textArea.setText(text);
}
}
public class Java extends JFrame {
private Button dugme;
private JFrame frame;
private Panel panel;
public Java() {
frame = new JFrame();
dugme = new Button();
panel = new Panel();
//super("test");
frame.setLayout(new BorderLayout());
frame.setTitle("test");
frame.setSize(300, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.add(dugme, BorderLayout.NORTH);
frame.add(panel, BorderLayout.CENTER);
}
public static void main(String[] args) {
Java app = new Java();
}
}
I want action listener to alter the text in the panel, sys-out works so the listener listens the button but I can't make it to alter the text in text area.

As already mentioned by #XtremeBaumer you have two different instances of Panel class. You need to remove the secode one.
public class Button extends JPanel {
private JButton button;
private Panel panel;
public Button(Panel panel) { // we need already created instance of panel here.
this.panel = panel;
button = new JButton("BUTTON");
// panel = new Panel(); <-- this line must be deleted.
// ...
}
}
public class Java extends JFrame {
private Button dugme;
private JFrame frame;
private Panel panel;
public Java(){
frame = new JFrame();
panel = new Panel();
dugme = new Button(panel);
// ...
}
}
Please also replace the line
add(textArea, BorderLayout.CENTER);
by
add(new JScrollPane(textArea), BorderLayout.CENTER);
This allows you to get the scrool bars when text goes larger than the text ara size.
Here is your reworked example
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
class Button extends JPanel {
private JButton button;
private Panel panel;
public Button(Panel panel) {
this.panel = panel;
button = new JButton("BUTTON");
add(button);
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JButton clicked = (JButton) e.getSource();
String input = clicked.getText();
panel.setTextArea(input);
//System.out.println(input);
}
});
}
}
class Panel extends JPanel {
private JTextArea textArea;
public Panel() {
setLayout(new BorderLayout());
textArea = new JTextArea();
add(new JScrollPane(textArea), BorderLayout.CENTER);
}
public JTextArea getTextArea() {
return textArea;
}
void setTextArea(String text) {
this.textArea.setText(text);
}
}
public class Java extends JFrame {
private Button dugme;
private JFrame frame;
private Panel panel;
public Java() {
frame = new JFrame();
panel = new Panel();
dugme = new Button(panel);
//super("test");
frame.setLayout(new BorderLayout());
frame.setTitle("test");
frame.setSize(300, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
frame.add(dugme, BorderLayout.NORTH);
frame.add(panel, BorderLayout.CENTER);
}
public static void main(String[] args) {
Java app = new Java();
}
}

JButton not responsive - have to click twice

I created a GUI using java swing and in a specific situation, the JButton is unresponsive and I have to click it twice. On the click, it takes the info in the textArea and sends it to a TextParser class to be parsed. If I type more stuff in the area after, and click the evaluateButton, it doesn't respond and I have to click it again to work. Does anyone know if this is a known bug or how I can fix this?
The code for the class is as follows.
/**
* Add the components to the GUI.
* #param pane - the pane for the GUI
*/
public static void addComponentsToPane(Container pane) {
pane.setLayout(new BorderLayout());
JPanel instructionsPanel = new JPanel();
JLabel instructions = new JLabel("Enter the email text below");
instructionsPanel.setBackground(Color.LIGHT_GRAY);
instructionsPanel.add(instructions);
pane.add(instructionsPanel, BorderLayout.NORTH);
JPanel textAreaPanel = new JPanel();
textAreaPanel.setBackground(Color.LIGHT_GRAY);
final JTextArea textArea = new JTextArea();
textArea.setBackground(Color.WHITE);
textArea.setMinimumSize(new Dimension(400,350));
textArea.setMaximumSize(new Dimension(400,350));
textArea.setPreferredSize(new Dimension(400,350));
textArea.setLineWrap(true);
Border border = BorderFactory.createLineBorder(Color.BLACK);
textArea.setBorder(border);
textArea.setMinimumSize(new Dimension(500, 200));
textArea.setFont(new Font("Serif", Font.PLAIN, 16));
textAreaPanel.add(textArea);
pane.add(textAreaPanel, BorderLayout.CENTER);
JPanel scoringPanel = new JPanel();
JButton evaluateButton = new JButton("Evaluate Email");
final JLabel scoreLabel = new JLabel("");
JButton uploadFileBtn = new JButton("Upload File");
JButton importTermsBtn = new JButton("Import Terms");
scoringPanel.add(evaluateButton);
scoringPanel.add(uploadFileBtn);
scoringPanel.add(importTermsBtn);
scoringPanel.add(scoreLabel);
pane.add(scoringPanel, BorderLayout.SOUTH);
evaluateButton.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
try {
String email = textArea.getText();
TextParser textParser = new TextParser(email);
double score = textParser.parse();
scoreLabel.setText(score+"");
} catch (Exception ex) {
System.out.println(ex);
}
}
});
uploadFileBtn.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
scoreLabel.setText("Feature not yet available.");
}
});
importTermsBtn.addMouseListener(new MouseAdapter() {
#Override
public void mouseClicked(MouseEvent e) {
DatabaseInput d = new DatabaseInput();
d.main(null);
}
});
}
/**
* Create the GUI and show it.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame("EmailGUI");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//frame.setLocationRelativeTo(null);
frame.setPreferredSize(new Dimension(500,500));
frame.setTitle("Email Text Input");
frame.setResizable(true);
Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
frame.setSize(screenSize.width, screenSize.height);
//Set up the content pane.
addComponentsToPane(frame.getContentPane());
//Display the window.
frame.pack();
frame.setVisible(true);
}
My main method just calls createAndShowGUI(). I am new to StackOverflow so if I need to give more or less information in my post please let me know!

As Reimeus and Jason C said in the comments, I should have been using ActionListener which works perfectly.

Getting Static from NonStatic Java (ActionListener)

From my action listener which I believe is static, im trying to call a non static method from a class. How can i call my method from my class?
public class addContent {
User Darryl = new User();
public static void addStuff(){
//Panel and Frame
JPanel panel = new JPanel(new BorderLayout());
JFrame frame = new JFrame("PandaHunterV3");
Container contentPane = frame.getContentPane();
contentPane.setLayout(new FlowLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Setup labels
JLabel label = new JLabel("Label");
frame.getContentPane().add(label);
//Setup buttons
JButton button = new JButton("Button");
frame.getContentPane().add(button);
//Action listener
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e){
Darryl.showHealth(); // HERE IS THE PROBLEM.
}
});
//Crap
frame.pack();
frame.setVisible(true);
}
}
and my class from which i am trying to call the methods from
public class User {
int health;
User(){
health = 50;
}
public void showHealth(){
System.out.print(health);
}
public void incHealth(){
health += 20;
}
}

EDIT:
Mark the Daryl instance as static or the method addStuff() as non-static.
btw. use low case for naming the variables / instances and upper-case for class names.
public class AddContent {
private User darryl = new User();
public void addStuff(){
//Panel and Frame
JPanel panel = new JPanel(new BorderLayout());
JFrame frame = new JFrame("PandaHunterV3");
Container contentPane = frame.getContentPane();
contentPane.setLayout(new FlowLayout());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
//Setup labels
JLabel label = new JLabel("Label");
frame.getContentPane().add(label);
//Setup buttons
JButton button = new JButton("Button");
frame.getContentPane().add(button);
//Action listener
button.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent e){
AddContent.this.darryl.showHealth(); // SHOULD BE FINE
}
});
//Crap
frame.pack();
frame.setVisible(true);
}
}

Adding buttons below JTextArea

I am trying to add two buttons below the JTextArea using the Eclipse WindowBuilder, but I can't. I tried to change the layout, but I couldn't find a way to add buttons where I want and to re-size the JTextArea in an easy way.
public TestScrollPane03() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
JTextArea textArea = new JTextArea(100, 50);
JScrollPane scrollPane = new JScrollPane(textArea);
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(scrollPane);
frame.setSize(200, 200);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
How would I go about adding buttons below my original textArea?

You need to have two panels, one for your textArea, and one for your input (in this case buttons). I think something like this is what you are looking for:
public class Test
{
public static void createFrame()
{
EventQueue.invokeLater(new Runnable()
{
#Override
public void run()
{
JFrame frame = new JFrame("Test");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
panel.setOpaque(true);
JTextArea textArea = new JTextArea(15, 50);
textArea.setWrapStyleWord(true);
textArea.setEditable(false);
textArea.setFont(Font.getFont(Font.SANS_SERIF));
JScrollPane scroller = new JScrollPane(textArea);
scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
JPanel inputpanel = new JPanel();
inputpanel.setLayout(new FlowLayout());
JTextField input = new JTextField(20);
JButton button = new JButton("Enter");
DefaultCaret caret = (DefaultCaret) textArea.getCaret();
caret.setUpdatePolicy(DefaultCaret.ALWAYS_UPDATE);
panel.add(scroller);
inputpanel.add(input);
inputpanel.add(button);
panel.add(inputpanel);
frame.getContentPane().add(BorderLayout.CENTER, panel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
frame.setResizable(false);
input.requestFocus();
}
});
}
public static void main(String... args)
{
createFrame();
}
}
If you want your frame to look more like those of the OS you are running on, you can add .setLookAndFeel() before you make the frame visible:
try
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception e) {
e.printStackTrace();
}
What adding the UIManager looks like (notably a bit smaller):

Adding JPanels from other classes to the cardLayout

I've got 3 windows in 3 separate classes and I would like to use cardLayout so that when you click the next button, the next window will appear. How do I add JPanels containing different elements to one cardLayout? This is the first window: (the only difference is the background though - but it represents the idea of how I got it actually)
public class Window1 extends JPanel implements ActionListener {
static CardLayout cardLayout = new CardLayout();
public Window1() {
init();
}
private void init() {
JPanel jp = new JPanel(new BorderLayout());
JPanel jp2 = new Window2();
//JPanel jp3 = new Window3();
JLabel textLabel = new JLabel("Window1");
jp.setBackground(Color.GREEN);
jp.add(textLabel, BorderLayout.CENTER);
JButton nextButton = new JButton("NEXT");
nextButton.setActionCommand("next");
nextButton.addActionListener(this);
jp.add(nextButton, BorderLayout.EAST);
setLayout(cardLayout);
add(jp, "string");
add(jp2, "string");
//add(jp3, "string");
}
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equalsIgnoreCase("next")) {
// go to the next window
cardLayout.next(this);
}
}
private static void createAndShowGUI() {
JFrame frame = new JFrame("test");
frame.getContentPane().setLayout(Window1.cardLayout);
frame.getContentPane().add(new Window1(), "Center");
frame.getContentPane().add(new Window2(), "Center");
frame.getContentPane().add(new Window3(), "Center");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(550, 450);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
}
The second window:
public class Window2 extends JPanel implements ActionListener {
//static CardLayout cardLayout = new CardLayout();
public Window2() {
init();
}
private void init() {
setLayout(new BorderLayout());
JLabel textLabel = new JLabel("Window2");
setBackground(Color.RED);
add(textLabel, BorderLayout.CENTER);
JButton nextButton = new JButton("NEXT");
nextButton.setActionCommand("next");
nextButton.addActionListener(this);
add(nextButton, BorderLayout.EAST);
//setLayout(cardLayout);
//JPanel jp3 = new Window3();
//add(jp3, "string");
}
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equalsIgnoreCase("next")) {
// go to the next window??
System.out.println("window2");
Window1.cardLayout.next(this);
}
}
}
And the last one:
public class Window3 extends JPanel implements ActionListener {
public Window3() {
init();
}
private void init() {
setLayout(new BorderLayout());
JLabel textLabel = new JLabel("Window3");
setBackground(Color.BLUE);
add(textLabel, BorderLayout.CENTER);
JButton nextButton = new JButton("NEXT");
nextButton.setActionCommand("next");
nextButton.addActionListener(this);
add(nextButton, BorderLayout.EAST);
}
public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equalsIgnoreCase("next")) {
// go to the next window
// Window1.cardLayout.next(this);
}
}
}

I had made a small program, hopefully the comments written in the program, might be able to guide you, to understand how to use CardLayout.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
/* Here we are first declaring our class that will act as the
* base for other panels or in other terms the base for CardLayout.
*/
public class CardLayoutTest
{
private static final String CARD_JBUTTON = "Card JButton";
private static final String CARD_JTEXTFIELD = "Card JTextField";
private static final String CARD_JRADIOBUTTON = "Card JRadioButton";
private static void createAndShowGUI()
{
JFrame frame = new JFrame("Card Layout Test");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLocationRelativeTo(null);
// This JPanel is the base for CardLayout for other JPanels.
final JPanel contentPane = new JPanel();
contentPane.setLayout(new CardLayout(20, 20));
/* Here we be making objects of the Window Series classes
* so that, each one of them can be added to the JPanel
* having CardLayout.
*/
Window1 win1 = new Window1();
contentPane.add(win1, CARD_JBUTTON);
Window2 win2 = new Window2();
contentPane.add(win2, CARD_JTEXTFIELD);
Window3 win3 = new Window3();
contentPane.add(win3, CARD_JRADIOBUTTON);
/* We need two JButtons to go to the next Card
* or come back to the previous Card, as and when
* desired by the User.
*/
JPanel buttonPanel = new JPanel();
final JButton previousButton = new JButton("PREVIOUS");
previousButton.setBackground(Color.BLACK);
previousButton.setForeground(Color.WHITE);
final JButton nextButton = new JButton("NEXT");
nextButton.setBackground(Color.RED);
nextButton.setForeground(Color.WHITE);
buttonPanel.add(previousButton);
buttonPanel.add(nextButton);
/* Adding the ActionListeners to the JButton,
* so that the user can see the next Card or
* come back to the previous Card, as desired.
*/
previousButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.previous(contentPane);
}
});
nextButton.addActionListener(new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
CardLayout cardLayout = (CardLayout) contentPane.getLayout();
cardLayout.next(contentPane);
}
});
// Adding the contentPane (JPanel) and buttonPanel to JFrame.
frame.add(contentPane, BorderLayout.CENTER);
frame.add(buttonPanel, BorderLayout.PAGE_END);
frame.pack();
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
createAndShowGUI();
}
});
}
}
class Window1 extends JPanel
{
/*
* Here this is our first Card of CardLayout, which will
* be added to the contentPane object of JPanel, which
* has the LayoutManager set to CardLayout.
* This card consists of Two JButtons.
*/
private ActionListener action;
public Window1()
{
init();
}
private void init()
{
final JButton clickButton = new JButton("CLICK ME");
final JButton dontClickButton = new JButton("DON\'T CLICK ME");
action = new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
if (ae.getSource() == clickButton)
{
JOptionPane.showMessageDialog(null, "Hello there dude!"
, "Right Button", JOptionPane.INFORMATION_MESSAGE);
}
else if (ae.getSource() == dontClickButton)
{
JOptionPane.showMessageDialog(null, "I told you not to click me!"
, "Wrong Button", JOptionPane.PLAIN_MESSAGE);
}
}
};
clickButton.addActionListener(action);
dontClickButton.addActionListener(action);
add(clickButton);
add(dontClickButton);
}
}
class Window2 extends JPanel implements ActionListener
{
/*
* Here this is our second Card of CardLayout, which will
* be added to the contentPane object of JPanel, which
* has the LayoutManager set to CardLayout.
* This card consists of a JLabel and a JTextField
* with GridLayout.
*/
private JTextField textField;
public Window2()
{
init();
}
private void init()
{
setLayout(new GridLayout(1, 2));
JLabel userLabel = new JLabel("Your Name : ");
textField = new JTextField();
textField.addActionListener(this);
add(userLabel);
add(textField);
}
public void actionPerformed(ActionEvent e)
{
if (textField.getDocument().getLength() > 0)
JOptionPane.showMessageDialog(null, "Your Name is : " + textField.getText()
, "User\'s Name : ", JOptionPane.QUESTION_MESSAGE);
}
}
class Window3 extends JPanel
{
/*
* Here this is our third Card of CardLayout, which will
* be added to the contentPane object of JPanel, which
* has the LayoutManager set to CardLayout.
* This card consists of Two JLabels and two JCheckBox
* with GridLayout.
*/
private ActionListener state;
public Window3()
{
init();
}
public void init()
{
setLayout(new GridLayout(2, 2));
JLabel maleLabel = new JLabel("MALE", JLabel.CENTER);
final JCheckBox maleBox = new JCheckBox();
JLabel femaleLabel = new JLabel("FEMALE", JLabel.CENTER);
final JCheckBox femaleBox = new JCheckBox();
state = new ActionListener()
{
public void actionPerformed(ActionEvent ae)
{
if (maleBox == (JCheckBox) ae.getSource())
{
femaleBox.setSelected(false);
JOptionPane.showMessageDialog(null, "Congrats you are a Male"
, "Gender : ", JOptionPane.INFORMATION_MESSAGE);
}
else if (femaleBox == (JCheckBox) ae.getSource())
{
maleBox.setSelected(false);
JOptionPane.showMessageDialog(null, "Congrats you are a Female"
, "Gender : ", JOptionPane.INFORMATION_MESSAGE);
}
}
};
maleBox.addActionListener(state);
femaleBox.addActionListener(state);
add(maleLabel);
add(maleBox);
add(femaleLabel);
add(femaleBox);
}
}

There are a couple things:
As your program can only run 1 main method, each class doesnt need one, but whichever you do run should create an instance of each panel you want to add to your CardLayout.
You also do not seem to add your Windows to your CardLayout at all. You could try the following (uncomplied). This would only be needed in one class:
private static void createAndShowGUI() {
JFrame frame = new JFrame("test");
frame.getContentPane().setLayout(Window1.cardLayout);
frame.getContentPane().add(new Window1());
frame.getContentPane().add(new Window2());
frame.getContentPane().add(new Window3());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(550, 450);
frame.setVisible(true);
}
Further (and this might just be due to the simplicity of your example), I would just have 1 class, and it would take the name of the panel and the color of the background to the constructor. These could be passed into your init() method and your design would be somewhat streamlined.