Develop Reference

Java - how to zoom in/zoom out text in JTextArea

I am writing in a notepad. And I want to implement text scaling in my notepad. But I don't know how to do it. I'm trying to find it but everyone is suggesting to change the font size. But I need another solution.
I am create new project and add buttons and JTextArea.
package zoomtest;
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JTextArea;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class zoom {
private JFrame frame;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
zoom window = new zoom();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public zoom() {
initialize();
}
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
frame.getContentPane().add(panel, BorderLayout.NORTH);
JButton ZoomIn = new JButton("Zoom in");
ZoomIn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
//Code here...
}
});
panel.add(ZoomIn);
JButton Zoomout = new JButton("Zoom out");
Zoomout.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
//Code here...
}
});
panel.add(Zoomout);
JTextArea jta = new JTextArea();
frame.getContentPane().add(jta, BorderLayout.CENTER);
}
}

Introduction
Oracle has a helpful tutorial, Creating a GUI With Swing. Skip the Learning Swing with the NetBeans IDE section. Pay close attention to the Laying Out Components Within a Container section.
I reworked your GUI. Here's how it looks when the application starts. I typed some text so you can see the font change.
Here's how it looks after we zoom out.
Here's how it looks after we zoom in.
Stack Overflow scales the images, so it's not as obvious that the text is zooming.
Explanation
Swing was designed to be used with layout managers. I created two JPanels, one for the JButtons and one for the JTextArea. I put the JTextArea in a JScrollPane so you could type more than 10 lines.
I keep track of the font size in an int field. This is a simple application model. Your Swing application should always have an application model made up of one or more plain Java getter/setter classes.
Code
Here's the complete runnable code.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
public class ZoomTextExample {
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
new ZoomTextExample();
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
private int pointSize;
private Font textFont;
private JFrame frame;
private JTextArea jta;
private JTextField pointSizeField;
public ZoomTextExample() {
this.pointSize = 16;
this.textFont = new Font(Font.DIALOG, Font.PLAIN, pointSize);
initialize();
}
private void initialize() {
frame = new JFrame("Text Editor");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(createButtonPanel(), BorderLayout.NORTH);
frame.add(createTextAreaPanel(), BorderLayout.CENTER);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
private JPanel createButtonPanel() {
JPanel panel = new JPanel(new FlowLayout());
panel.setBorder(BorderFactory.createEmptyBorder(0, 5, 5, 5));
JButton zoomIn = new JButton("Zoom in");
zoomIn.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
incrementPointSize(+2);
updatePanels();
}
});
panel.add(zoomIn);
panel.add(Box.createHorizontalStrut(20));
JLabel label = new JLabel("Current font size:");
panel.add(label);
pointSizeField = new JTextField(3);
pointSizeField.setEditable(false);
pointSizeField.setText(Integer.toString(pointSize));
panel.add(pointSizeField);
panel.add(Box.createHorizontalStrut(20));
JButton zoomOut = new JButton("Zoom out");
zoomOut.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent event) {
incrementPointSize(-2);
updatePanels();
}
});
panel.add(zoomOut);
return panel;
}
private JPanel createTextAreaPanel() {
JPanel panel = new JPanel(new BorderLayout());
panel.setBorder(BorderFactory.createEmptyBorder(0, 5, 5, 5));
jta = new JTextArea(10, 40);
jta.setFont(textFont);
JScrollPane scrollPane = new JScrollPane(jta);
panel.add(scrollPane, BorderLayout.CENTER);
return panel;
}
private void updatePanels() {
pointSizeField.setText(Integer.toString(pointSize));
textFont = textFont.deriveFont((float) pointSize);
jta.setFont(textFont);
frame.pack();
}
private void incrementPointSize(int increment) {
pointSize += increment;
}
}

JPanel.remove not working with JButton actionListener? [duplicate]

The idea is to have one "global" JFrame which I can then add/remove JPanels as needed to make a smooth flowing application. Currently, when I try changing from the first JPanel to the second, the second won't display. My code is below:
Handler (class to run the app):
package com.example.Startup;
import com.example.Global.Global_Frame;
public class Handler
{
public Handler()
{
gf = new Global_Frame();
gf.getAccNum();
gf.setVisible(true);
}
public static void main(String[] args)
{
new Handler();
}
Global_Frame gf = null;
}
public static void main(String[] args)
{
new Handler();
}
Global_Vars gv = null;
Global_Frame gf = null;
}
Global Frame:
package com.example.Global;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFrame;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import com.example.FirstRun.AccDetails;
import com.example.FirstRun.FirstTimeRun;
public class Global_Frame extends JFrame
{
private static final long serialVersionUID = 1L;
ActionListener val = new ActionListener()
{
public void actionPerformed(ActionEvent e)
{
getUserDetails();
}
};
public Global_Frame()
{
try
{
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); // get look and feel based on OS
}
catch (ClassNotFoundException ex) // catch all errors that may occur
{
Logger.getLogger(Global_Frame.class.getName()).log(Level.SEVERE, null, ex);
}
catch (InstantiationException ex)
{
Logger.getLogger(Global_Frame.class.getName()).log(Level.SEVERE, null, ex);
}
catch (IllegalAccessException ex)
{
Logger.getLogger(Global_Frame.class.getName()).log(Level.SEVERE, null, ex);
}
catch (UnsupportedLookAndFeelException ex)
{
Logger.getLogger(Global_Frame.class.getName()).log(Level.SEVERE, null, ex);
}
EventQueue.invokeLater(new Runnable()
{
public void run() //run the class's constructor, therefore starting the UI being built
{
initComponents();
}
});
}
public void initComponents()
{
setPreferredSize(new Dimension(600, 400)); // setting measurements of jframe
revalidate(); // revalidate the elements that will be displayed
repaint(); // repainting what is displayed if going coming from a different form
pack(); // packaging everything up to use
setLocationRelativeTo(null); // setting form position central
}
public void getAccNum()
{
setPreferredSize(new Dimension(600, 400)); // setting measurements of jframe
FirstTimeRun panel1 = new FirstTimeRun(val);
add(panel1);
revalidate();
repaint();
pack();
}
public void getUserDetails()
{
getContentPane().removeAll();
resizing(750, 500);
AccDetails panel2 = new AccDetails();
add(panel2);
revalidate();
repaint();
pack();
}
private void resizing(int width, int height)
{
timer = new Timer (10, new ActionListener() {
#Override
public void actionPerformed(ActionEvent arg0)
{
getContentPane().removeAll();
setPreferredSize(new Dimension(sizeW, sizeH));
revalidate();
repaint();
pack();
if (!wToggle)
sizeW += 2;
if (!hToggle)
sizeH += 2;
if (toggle)
{
setLocationRelativeTo(null);
toggle = false;
}
else
toggle = true;
if (sizeW == width)
wToggle = true;
if (sizeH == height)
hToggle = true;
if (hToggle && wToggle)
timer.stop();
}
});
timer.start();
}
//variables used for window resizing
private Timer timer;
private int sizeW = 600;
private int sizeH = 400;
private boolean toggle = false;
private boolean wToggle = false;
private boolean hToggle = false;
public int accNum = 0;
}
First Panel:
package com.example.FirstRun;
import java.awt.Dimension;
import java.awt.event.ActionListener;
import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JPanel;
public class FirstTimeRun extends JPanel
{
private static final long serialVersionUID = 1L;
public FirstTimeRun()
{
}
public FirstTimeRun(ActionListener val)
{
initComponents(val);
}
private void initComponents(ActionListener val) // method to build initial view for user for installation
{
pnlStart = new JPanel[1];
btnNext = new JButton();
pnlStart[0] = new JPanel();
btnNext.setText("Next"); // adding text to button for starting
btnNext.setPreferredSize(new Dimension(80, 35)); //positioning start button
btnNext.addActionListener(val);
pnlStart[0].add(btnNext); // adding button to JFrame
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
add(pnlStart[0]);
}
// objects used in UI
private JPanel[] pnlStart;
private JButton btnNext;
}
Second Panel:
package com.example.FirstRun;
import java.awt.BorderLayout;
import javax.swing.Box;
import javax.swing.BoxLayout;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class AccDetails extends JPanel
{
private static final long serialVersionUID = 1L;
public AccDetails()
{
accAssets();
}
private void accAssets()
{
// instantiating elements of the GUI
pnlAccDetails = new JPanel[2];
lblWelcome = new JLabel();
lblMain = new JLabel();
for (int i = 0; i < 2; i++)
pnlAccDetails[i] = new JPanel();
lblWelcome.setText("Welcome to Example_App"); // label welcoming user
pnlAccDetails[0].setLayout(new BoxLayout(pnlAccDetails[0], BoxLayout.LINE_AXIS));
pnlAccDetails[0].add(lblWelcome); // adding label to form
lblMain.setText("<html>The following information that is collected will be used as part of the Example_App process to ensure that each user has unique Example_App paths. Please fill in all areas of the following tabs:</html>"); // main label that explains what happens, html used for formatting
pnlAccDetails[1].setLayout(new BorderLayout());
pnlAccDetails[1].add(Box.createHorizontalStrut(20), BorderLayout.LINE_START);
pnlAccDetails[1].add(lblMain, BorderLayout.CENTER); //adding label to JFrame
pnlAccDetails[1].add(Box.createHorizontalStrut(20), BorderLayout.LINE_END);
setLayout(new BoxLayout(this, BoxLayout.PAGE_AXIS));
add(pnlAccDetails[0]);
add(pnlAccDetails[1]);
}
private JLabel lblWelcome;
private JLabel lblMain;
private JPanel[] pnlAccDetails;
}
I have tried using both a CardLayout and the "revalidate();" "repaint();" and "pack();" options and I'm stumped as to why it's not showing. Thanks in advance for any help that can be offered.
EDIT:
While cutting down my code, if the "resizing" method is removed, the objects are shown when the panels change. I would like to avoid having to remove this completely as it's a smooth transition for changing the JFrame size.

#John smith it is basic example of switch from one panel to other panel I hope this will help you to sort out your problem
Code:
package stack;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class RemoveAndAddPanel implements ActionListener{
JFrame frame;
JPanel firstPanel;
JPanel secondPanel;
JPanel controlPanel;
JButton nextButton;
public RemoveAndAddPanel() {
JFrame.setDefaultLookAndFeelDecorated(true);
frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
firstPanel = new JPanel();
firstPanel.add(new JLabel("FirstPanel"));
firstPanel.setPreferredSize(new Dimension(100,100));
secondPanel = new JPanel();
secondPanel.add(new JLabel("Second panel"));
secondPanel.setPreferredSize(new Dimension(100,100));
nextButton = new JButton("Next panel");
controlPanel = new JPanel();
nextButton.addActionListener(this);
controlPanel.add(nextButton);
frame.setLayout(new BorderLayout());
frame.add(firstPanel,BorderLayout.CENTER);
frame.add(controlPanel, BorderLayout.SOUTH);
frame.setVisible(true);
frame.setSize(300,100);
}
#Override
public void actionPerformed(ActionEvent e) {
if(e.getSource() == nextButton) {
frame.remove(firstPanel);
frame.add(secondPanel);
nextButton.setEnabled(false);
}
frame.validate();
}
public static void main(String args[]) {
new RemoveAndAddPanel();
}
}

As mentioned in the edit, the problem lay within the resizing method. When the timer stopped, it wouldn't go anywhere, causing the UI to not load. The fix to the code is clearing the screen and adding the call to resizing to the actionlistener. Then adding a call to the next method after:
timer.stop();
Thanks for getting me to remove the mess around it and find the source of the problem #matt & #Hovercraft Full of Eels upvotes for both of you.

The main thing to consider while changing panel in a jframe is the layout, for a body(main) panel to change to any other panel the parent panel must be of type CardLayout body.setLayout(new java.awt.CardLayout());
After that you can now easily switch between panels wiht the sample code below
private void updateViewLayout(final HomeUI UI, final JPanel paneeelee){
final JPanel body = UI.getBody(); //this is the JFrame body panel and must be of type cardLayout
System.out.println("Page Loader Changing View");
new SwingWorker<Object, Object>() {
#Override
protected Object doInBackground() throws Exception {
body.removeAll();//remove all visible panel before
body.add(paneeelee);
body.revalidate();
body.repaint();
return null;
}
#Override
protected void done() {
UI.getLoader().setVisible(false);
}
}.execute();
}

When does a Java Swing JScrollBar update its size?

I have a JTextArea in a JScrollPane, to which I append messages with display.append(). I am trying to make it scroll automatically by setting the value of the scroll bar to the maximum after appending the text. However, the value of getVerticalScrollBar().getMaximum()doesn't get updated immediately after a line is appended. I have tried to force an update with revalidate(), repaint() and updateUI(), but seem unable to find the right function.
MWE:
import java.awt.BorderLayout;
import java.awt.Font;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JScrollBar;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.SwingUtilities;
public class MessageDisplayPane extends JScrollPane {
private static final long serialVersionUID = 2025745714938834689L;
public static final int NUM_LINES = 5;
private JTextArea display;
private JScrollBar vertical = getVerticalScrollBar();
public MessageDisplayPane() {
display = createTextArea();
setViewportView(display);
}
private JTextArea createTextArea() {
JTextArea ta = new JTextArea(NUM_LINES, 0);
ta.setEditable(false);
ta.setLineWrap(true);
ta.setWrapStyleWord(true);
ta.setFont(new Font("Arial", Font.PLAIN, 12));
ta.setBorder(BorderFactory.createEtchedBorder());
return ta;
}
class EventListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
new Thread() {
#Override
public void run() {
System.out.println(vertical.getMaximum());
display.append("test\r\n");
revalidate();
repaint();
updateUI();
System.out.println(vertical.getMaximum());
System.out.println();
//vertical.setValue(vertical.getMaximum());
}
}.start();
}
}
public static void main(String[] args) {
JFrame.setDefaultLookAndFeelDecorated(true);
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
JFrame frame = new JFrame();
MessageDisplayPane messagePane = new MessageDisplayPane();
JButton button = new JButton("Display another line");
frame.setSize(800, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.getContentPane().add(button, BorderLayout.CENTER);
frame.getContentPane().add(messagePane, BorderLayout.SOUTH);
button.addActionListener(messagePane.new EventListener());
frame.setVisible(true);
}
});
}
}

A possible solution could be to set the caret position to the end (or the beginning) of your text, something like :
textArea.setCaretPosition (textArea.getText ().length ()); // to scroll to the bottom
textArea.setCaretPosition (0); // to scroll to the top
I used a similar instruction to set caret position to 0, and the scrollbar did automatically scroll to the top, so it should work for you.

Using button in a panel class to call ActionListener in the frame class

I started codig Java last weekend and I've read most of the basic stuff. I'm trying to separate my frame from main method, and panels from the frame so they are all in separate class files. I have trouble calling ActionLister in "Frame1" class with a button (buttonBack) in the "TheGame" class. The button should trigger the Listener which in turn should remove theGame panel and add mainMenu panel to frame1. I know that CardLayout is better suited for swapping panels but i want to learn the limits and workarounds before i go do it the "easy" way, i feel that you learn much more that way.
Here is some of my code:
Main:
public class Main {
public static void main(String[] args){
Frame1 frame1 = new Frame1();
frame1.frame1();
}
}
Frame1:
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
class Frame1 {
private JFrame frame1 = new JFrame("Name");
public void frame1() {
TheGame theGame = new TheGame();
MainMenu mainMenu = new MainMenu();
// Frame options
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setLocationRelativeTo(null);
// Creating a top menu
JMenuBar menubar = new JMenuBar();
frame1.setJMenuBar(menubar);
JMenu file = new JMenu("File");
menubar.add(file);
JMenu help = new JMenu("Help");
menubar.add(help);
JMenuItem exit = new JMenuItem("Exit");
file.add(exit);
JMenuItem about = new JMenuItem("About");
help.add(about);
// Creating action for the menuitem "exit".
class exitaction implements ActionListener{
public void actionPerformed (ActionEvent e){
System.exit(0);
}
}
exit.addActionListener(new exitaction());
// Creating listener for the menuitem "about".
class aboutaction implements ActionListener{
public void actionPerformed (ActionEvent e){
JDialog dialogabout = new JDialog();
JOptionPane.showMessageDialog(dialogabout, "Made by: ");
}
}
about.addActionListener(new aboutaction());
// Add the panels, pack and setVisible
theGame.theGame();
mainMenu.mainMenu();
frame1.add(theGame.getGUI());
// This is the ActionListener i have trouble connecting with the buttonBack in the "theGame" class
class Action implements ActionListener{
public void actionPerformed (ActionEvent e){
frame1.remove(theGame.getGUI());
frame1.add(MainMenu.getGUI());
}
}
frame1.pack();
frame1.setVisible(true);
}
public JFrame getGUI() {
return frame1;
}
}
MainMenu:
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
class MainMenu {
private JPanel mainMenu = new JPanel (new GridBagLayout());
public void mainMenu() {
// Using the GridBagLayout therefore creating the constraints "grid"
GridBagConstraints grid = new GridBagConstraints();
// Adjusting grid insets
grid.insets = new Insets(10, 10, 10, 10);
// Creating Label
JLabel introduction = new JLabel("Name");
grid.gridx = 1;
grid.gridy = 3;
mainMenu.add(introduction, grid);
// Creating buttons Start Game, Highscore and Exit Game
JButton buttonNewGame = new JButton("New Game");
buttonNewGame.setPreferredSize(new Dimension(200, 50));
grid.gridx = 1;
grid.gridy = 5;
mainMenu.add(buttonNewGame, grid);
JButton buttonHighscore = new JButton("Highscore");
buttonHighscore.setPreferredSize(new Dimension(200, 50));
grid.gridx = 1;
grid.gridy = 6;
mainMenu.add(buttonHighscore, grid);
JButton buttonExit = new JButton("Exit Game");
buttonExit.setPreferredSize(new Dimension(200, 50));
grid.gridx = 1;
grid.gridy = 7;
mainMenu.add(buttonExit, grid);
}
public JComponent getGUI() {
return mainMenu;
}
}
TheGame:
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
class TheGame {
private JPanel theGame = new JPanel (new GridBagLayout());
public void theGame() {
// Using the GridBagLayout therefore creating the constraints "grid"
GridBagConstraints grid = new GridBagConstraints();
// Adjusting grid insets
grid.insets = new Insets(10, 10, 10, 10);
// Creating a label
JLabel label1 = new JLabel("Press the BACK button to go back to Main Menu");
label1.setVisible(true);
grid.gridx = 1;
grid.gridy = 0;
theGame.add(label1,grid);
// Creating BACK button
JButton buttonBack = new JButton("BACK");
buttonBack.setVisible(true);
grid.gridx = 1;
grid.gridy = 1;
buttonBack.addActionListener(new --); // This is the button i want to connect with the ActionListener on Frame1 class
theGame.add(buttonBack, grid);
}
public JComponent getGUI() {
return theGame;
}
}
I've tried moving the ActionListener outside of methods, inside the Main, declaring it static, but haven't been able to call it anyways. I've also looked at other posts like this: Add an actionListener to a JButton from another class but have not been able to implement it in to my code.
Any help is appreciated.

The best answer -- use MVC (model-view-controller) structure (and CardLayout) for the swapping of your views. If you don't want to do that, then your listener should have a reference to the container that does the swapping, and so that the listener can notify this container that a swap should occur. The container will then call its own code to do the swapping. To do this you need to pass references around including a reference to the main GUI to wherever it is needed. This can get messy, which is why MVC, which is more work, is usually better -- fewer connections/complexity in the long term.
Side note -- don't pass a JDialog into a JOptionPane as a JOptionPane is a specialized JDialog, and you shouldn't have a top level window displaying a top level window. Instead pass in a JPanel.
For example:
import java.awt.CardLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import javax.swing.*;
public class PassRef {
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
private static void createAndShowGui() {
MyMain mainPanel = new MyMain();
JFrame frame = new JFrame("Pass Reference");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
}
class MyMain extends JPanel {
private static final int PREF_W = 600;
private static final int PREF_H = 450;
private CardLayout cardLayout = new CardLayout();
private MenuView menuView = new MenuView(this);
private ActionView1 actionView1 = new ActionView1(this);
public MyMain() {
setLayout(cardLayout);
add(menuView, MenuView.NAME);
add(actionView1, ActionView1.NAME);
}
#Override
public Dimension getPreferredSize() {
if (isPreferredSizeSet()) {
return super.getPreferredSize();
} else {
return new Dimension(PREF_W, PREF_H);
}
}
public void showCard(String key) {
cardLayout.show(this, key);
// or swap by hand if you don't want to use CardLayout
// but remember to revalidate and repaint whenever doing it by hand
}
}
class MenuView extends JPanel {
public static final String NAME = "Menu View";
public MenuView(MyMain myMain) {
setName(NAME);
setBorder(BorderFactory.createTitledBorder("Menu"));
add(new JButton(new GoToAction("Action 1", ActionView1.NAME, myMain)));
}
}
class ActionView1 extends JPanel {
public static final String NAME = "Action View 1";
public ActionView1(MyMain myMain) {
setName(NAME);
setBorder(BorderFactory.createTitledBorder(NAME));
add(new JButton(new GoToAction("Main Menu", MenuView.NAME, myMain)));
}
}
class GoToAction extends AbstractAction {
private String key;
private MyMain myMain;
public GoToAction(String name, String key, MyMain myMain) {
super(name);
this.key = key;
this.myMain = myMain;
}
#Override
public void actionPerformed(ActionEvent e) {
myMain.showCard(key);
}
}

Add and remove button dynamically in Swing frame

I'm developing a swing application. In that I've a JFrame which add JTextfield and JButton dynamically on the button click.and remove the created components if the user clicks the same button.
In the below screen image , when user clicks ADD button new row was added, and text was changed to REMOVE like in 2nd image.
New Row added and previous button text changed to REMOVE.
Now, if I click the REMOVE button, then the newly added row has to dispose and then button has to change the text again to ADD.
I've tried till adding the components, but I stuck up with removing the newly added row.
Anyone please guide me to achieve this.
Below is my code.
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.util.ArrayList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JRootPane;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class ButtonAddDynamic implements ActionListener {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new ButtonAddDynamic().createAndShowGUI();
}
});
}
private JFrame frame;
private JPanel panel = new JPanel(new GridBagLayout());
private GridBagConstraints constraints = new GridBagConstraints();
private List fields = new ArrayList();
private List fieldButton = new ArrayList();
private List fieldFile = new ArrayList();
private static int countReport = 0;
String files = null;
int y = 2;
protected void createAndShowGUI() {
try {
UIManager
.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel");
} catch (UnsupportedLookAndFeelException ex) {
ex.printStackTrace();
} catch (InstantiationException ex) {
ex.printStackTrace();
} catch (ClassNotFoundException ex) {
ex.printStackTrace();
} catch (IllegalAccessException ex) {
ex.printStackTrace();
}
String[] labels = { "VALIDATION FORM" };
for (String label : labels)
addColumn(label);
frame = new JFrame("Add Button Dynamically");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new JScrollPane(panel));
frame.setLocationRelativeTo(null);
frame.setResizable(false);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
// Set the default button to button1, so that when return is hit, it
// will hit the button1
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent we) {
System.exit(0);
}
});
}
private void addColumn(String labelText) {
constraints.gridx = fields.size();
constraints.gridy = 1;
panel.add(new JLabel(labelText), constraints);
constraints.gridy = 2;
final JTextField field = new JTextField(40);
field.setEditable(false);
panel.add(field, constraints);
fields.add(field);
// constraints.gridy=3;
constraints.gridx = fields.size() + fieldButton.size();
final JButton button = new JButton("ADD");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
if (button.getText().equals("ADD")) {
button.setText("REMOVE");
addRowBelow();
frame.pack();
} else if (button.getText().equals("REMOVE")) {
button.setText("ADD");
frame.pack();
}
}
});
panel.add(button, constraints);
fieldButton.add(button);
panel.revalidate(); // redo layout for extra column
}
private void addRowBelow() {
y++;
constraints.gridy = y;
// System.out.println(fields.size());
for (int x = 0; x < fields.size(); x++) {
constraints.gridx = x;
final JTextField field = new JTextField(40);
field.setEditable(false);
panel.add(field, constraints);
constraints.gridx = x + 1;
final JButton button = new JButton("ADD");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
if (button.getText().equals("ADD")) {
button.setText("REMOVE");
addRowBelow();
frame.pack();
} else if (button.getText().equals("REMOVE")) {
button.setText("ADD");
frame.pack();
}
}
});
panel.add(button, constraints);
}
}
public void actionPerformed(ActionEvent ae) {
if ("Add Another TextField and Button".equals(ae.getActionCommand())) {
addRowBelow();
frame.pack();
frame.setLocationRelativeTo(null);
}
}
}

Trying to use GridBagLayout is making this very complicated for you. A nested layout scheme is much easier to work with when you are doing this type of thing.
See this MCVE:
I'm not sure I understood your intended functionality 100% correct but I don't think it's as important as the layouts.
My layout scheme is as follows:
This is nice because BoxLayout will handle the vertical listing without much hullabaloo. Instead of having to wrangle with GridBagConstraints, the text field and button are contained together by a panel.
import javax.swing.*;
import java.awt.event.*;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Insets;
public class FieldList implements Runnable, ActionListener {
public static void main(String... args) {
SwingUtilities.invokeLater(new FieldList());
}
final int maxFields = 2;
JFrame frame;
JPanel listing;
#Override
public void run() {
frame = new JFrame("Text Field Listing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel content = new JPanel(new BorderLayout());
content.add(new JLabel("Input Form", JLabel.CENTER), BorderLayout.NORTH);
listing = new JPanel();
listing.setLayout(new BoxLayout(listing, BoxLayout.Y_AXIS));
content.add(listing, BorderLayout.CENTER);
frame.setContentPane(content);
addNewField();
frame.pack();
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
void addNewField() {
FieldButtonPair field = new FieldButtonPair();
field.button.addActionListener(this);
listing.add(field);
frame.pack();
}
void removeLastField() {
listing.remove(listing.getComponentCount() - 1);
frame.pack();
}
#Override
public void actionPerformed(ActionEvent ae) {
AddRemoveButton source = (AddRemoveButton)ae.getSource();
if(source.state == AddRemoveButton.State.ADD) {
if(listing.getComponentCount() < maxFields) {
addNewField();
source.setState(AddRemoveButton.State.REMOVE);
}
} else if(source.state == AddRemoveButton.State.REMOVE) {
removeLastField();
source.setState(AddRemoveButton.State.ADD);
}
}
}
class FieldButtonPair extends JPanel {
JTextField field;
AddRemoveButton button;
FieldButtonPair() {
super(new BorderLayout());
field = new JTextField();
add(field, BorderLayout.CENTER);
button = new AddRemoveButton();
add(button, BorderLayout.EAST);
}
#Override
public Dimension getPreferredSize() {
Dimension pref = super.getPreferredSize();
pref.width = Math.max(480, pref.width);
return pref;
}
}
class AddRemoveButton extends JButton {
enum State { ADD, REMOVE }
State state = State.ADD;
AddRemoveButton() {
setText(state.name());
}
void setState(State state) {
setText(state.name());
this.state = state;
}
#Override
public Dimension getPreferredSize() {
Dimension pref = super.getPreferredSize();
Font f = getFont();
FontMetrics fm = getFontMetrics(f);
int w = fm.stringWidth(State.REMOVE.name());
Insets ins = getInsets();
pref.width = (ins.left + w + ins.right);
return pref;
}
}