Refresh JFrame with ActionListener - java

This has been asked many times already, but i really cant solve this problem.
I'm trying to refresh a table in a JFRame while it is running after i added a row so I dont have to restart it.I've tried the following method, but it still doesnt work.
The method is used in a ActionListener.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.JButton;
#SuppressWarnings("serial")
public class GUI2 extends JFrame {
private static JPanel contentPane;
private static JTable table;
/**
* Launch the application.
*/
public static void main(String[] args) {
GUI2 frame = new GUI2();
}
/**
* Create the frame.
*/
public GUI2() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
contentPane = new JPanel();
setContentPane(contentPane);
table = new JTable();
contentPane.add(table, BorderLayout.CENTER);
JButton btnRefresh = new JButton("Refresh");
contentPane.add(btnRefresh, BorderLayout.NORTH);
btnRefresh.addActionListener(new Refresh());
}
public class Refresh implements ActionListener{
public void actionPerformed(ActionEvent e){
repaintGUI();
}
}
public static void repaintGUI() {
contentPane.repaint();
contentPane.validate();
table.repaint();
table.validate();
}
}
Something similar to that. The Button is pressed after i have changed something in the table.


Your posted code doesn't work well as an example since the JTable is not visualized, but if you give the contentPane a BorderLayout, the JTable displays, and if refresh is pushed, then the GUI does in fact repaint, but as expected, it doesn't change its appearance since a simple repaint or revalidate won't change appearances if nothing else is done.
OK, here's where I need to guess since your question is still lacking key details (in the future, please ask it with an eye towards our point of view: people who have no idea what your current program does, looks like or what your problem is), but if the problem is that you're trying to reset a JTable's data, then the solution is to do just that -- reset your JTable's model by calling setRowCount(0) which will remove all data from the JTable, if it uses a DefaultTableModel. If it doesn't use the DefaultTableModel, then make sure to either give the JTable a new table model, or else call a method of your own table model that removes all data.
For instance:
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.util.Random;
import javax.swing.*;
import javax.swing.table.DefaultTableModel;
public class GUI3 extends JPanel {
private static final String[] COLS = { "Foo", "Bar", "Baz" };
private static final int ROWS = 5;
private DefaultTableModel tableModel = new DefaultTableModel(COLS, ROWS);
private JTable table = new JTable(tableModel);
private ResetAction resetAction = new ResetAction("Reset", KeyEvent.VK_R);
private RandomizeAction randomizeAxn = new RandomizeAction("Randomize",
KeyEvent.VK_Z);
public GUI3() {
JPanel btnPanel = new JPanel();
btnPanel.add(new JButton(resetAction));
btnPanel.add(new JButton(randomizeAxn));
setLayout(new BorderLayout());
add(new JScrollPane(table));
add(btnPanel, BorderLayout.PAGE_END);
}
private class ResetAction extends AbstractAction {
public ResetAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
tableModel.setRowCount(0);
}
}
private class RandomizeAction extends AbstractAction {
private Random random = new Random();
public RandomizeAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
public void actionPerformed(ActionEvent e) {
tableModel.setRowCount(ROWS);
int rows = ROWS;
int columns = tableModel.getColumnCount();
for (int row = 0; row < rows; row++) {
for (int col = 0; col < columns; col++) {
int data = random.nextInt(10);
tableModel.setValueAt(data, row, col);
}
}
};
}
private static void createAndShowGui() {
GUI3 mainPanel = new GUI3();
JFrame frame = new JFrame("GUI3");
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
frame.getContentPane().add(mainPanel);
frame.pack();
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}

Related

JPanel not changing on JFrame

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();
}

delete/empty gridLayout from Panel

I have a grid layout that is 9x9 and generates Jtextareas to fill it. If the user presses a button i want the grid layout to become empty again so i can refill it again but with no relation to what it previously was filled with.
is there some sort of command like gridlayout.delete() or something?

I'm guessing that you want to clear the text components that are held by the GridLayout-using container (you don't tell us, and please understand that this is key information about your question). If so, put them into a collection such as an ArrayList and iterate through the list calling setText("") within the loop.
If you're using Java 8, then this "for loop" can be replaced with a forEach(...) call on a Stream. For example, if you have an ArrayList like so:
List<JTextComponent> textComponentList = new ArrayList<>();
Then you can clear all the text components it holds with this call:
textComponentList.stream().forEach(tc -> tc.setText(""));
For example:
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.List;
import javax.swing.*;
import javax.swing.text.JTextComponent;
#SuppressWarnings("serial")
public class ClearGrid extends JPanel {
private static final int ROWS = 9;
private static final int COLS = ROWS;
private static final int GAP = 2;
private static final Font FONT = new Font(Font.SANS_SERIF, Font.BOLD, 32);
private static final int FIELD_COLS = 2;
List<JTextComponent> textComponentList = new ArrayList<>();
public ClearGrid() {
JPanel gridPanel = new JPanel(new GridLayout(ROWS, COLS, GAP, GAP));
gridPanel.setBackground(Color.BLACK);
for (int i = 0; i < ROWS; i++) {
for (int j = 0; j < COLS; j++) {
JTextField textField = new JTextField(FIELD_COLS);
textField.setFont(FONT);
textField.setHorizontalAlignment(JTextField.CENTER);
textComponentList.add(textField);
gridPanel.add(textField);
}
}
JPanel buttonPanel = new JPanel();
buttonPanel.add(new JButton(new ClearAllAction("Clear All", KeyEvent.VK_C)));
setLayout(new BorderLayout());
add(gridPanel);
add(buttonPanel, BorderLayout.PAGE_END);
}
private class ClearAllAction extends AbstractAction {
public ClearAllAction(String name, int mnemonic) {
super(name);
putValue(MNEMONIC_KEY, mnemonic);
}
#Override
public void actionPerformed(ActionEvent e) {
textComponentList.stream().forEach(tc -> tc.setText(""));
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("ClearGrid");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new ClearGrid());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(() -> {
createAndShowGui();
});
}
}

JTable inside a JScrollPane not showing up properly

I am working on a the GUI of a piece of code that I have been patching together. I am stuck at this part of the program where I would like a datafile the user chooses to be displayed in a JTable in a preview manner (i.e. the user should not be able to edit the data on the table).
With a button click from Experiment Parameters tab (see screenshot below), I create and run a "PreviewAction" which creates a new tab, and fills it up with the necessary components. Below is the code for DataPreviewAction. EDIT: I also posted a self-contained, minimal version of this that mimics the conditions in the real project, and exhibits the same behaviour.
import java.awt.BorderLayout;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
public class MyFrame extends JFrame {
private JPanel panel1;
private JTabbedPane tabs;
private JButton runButton;
public MyFrame() {
tabs = new JTabbedPane();
panel1 = new JPanel();
runButton = new JButton("go!");
runButton.addActionListener(new java.awt.event.ActionListener() {
public void actionPerformed(java.awt.event.ActionEvent evt) {
runButtonActionPerformed(evt);
}
});
panel1.add(runButton);
tabs.addTab("first tab", panel1);
this.add(tabs);
pack();
}
public static void main(String args[]) {
try {
for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager
.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
javax.swing.UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException ex) {
java.util.logging.Logger.getLogger(MyFrame.class.getName()).log(
java.util.logging.Level.SEVERE, null, ex);
} catch (InstantiationException ex) {
java.util.logging.Logger.getLogger(MyFrame.class.getName()).log(
java.util.logging.Level.SEVERE, null, ex);
} catch (IllegalAccessException ex) {
java.util.logging.Logger.getLogger(MyFrame.class.getName()).log(
java.util.logging.Level.SEVERE, null, ex);
} catch (javax.swing.UnsupportedLookAndFeelException ex) {
java.util.logging.Logger.getLogger(MyFrame.class.getName()).log(
java.util.logging.Level.SEVERE, null, ex);
}
/* Create and display the form */
java.awt.EventQueue.invokeLater(new Runnable() {
public void run() {
MyFrame frame = new MyFrame();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
private void runButtonActionPerformed(java.awt.event.ActionEvent evt) {
/*
* Normally there is more stuff happening here but this much will do for
* the sake of example
*/
List<String[]> data = new LinkedList<String[]>();
for (int i = 1; i < 1000; i++)
data.add(new String[] { "entry1", "value1", "value2", "value3" });
SwingUtilities.invokeLater(new DataPreviewAction(data, tabs));
}
public class DataPreviewAction implements Runnable {
private JTabbedPane contentHolder;
private List<String[]> data;
public DataPreviewAction(List<String[]> data, JTabbedPane comp) {
this.contentHolder = comp;
this.data = data;
}
#Override
public void run() {
DefaultTableModel previewModel = new DefaultTableModel() {
#Override
public boolean isCellEditable(int row, int column) {
return false;
}
};
for (String[] datarow : data) {
previewModel.addRow(Arrays.copyOf(datarow, datarow.length,
Object[].class));
}
JTable table = new JTable(previewModel);
JPanel buttonPanel = new JPanel();
buttonPanel.add(new JButton("A button"));
buttonPanel.add(new JLabel(
"Some description for the awesome table below "));
buttonPanel.add(new JButton("another button"));
JScrollPane tablePanel = new JScrollPane(table);
JPanel container = new JPanel();
container.setLayout(new BorderLayout());
container.add(buttonPanel, BorderLayout.NORTH);
container.add(tablePanel, BorderLayout.CENTER);
contentHolder.addTab("Preview", container);
contentHolder.validate();
contentHolder.repaint();
}
}
}
There are at least two problems here:
The JTable (or the JScrollPane) does not render at all
The JScrollPane is not as wide as the frame itself, I have no idea why
I am not all that good in Swing so I might be missing something fundamental. I have checked that the datafile is read properly, and the data model contains the right amount of rows (1000+). SO the table should not be empty.
Suggestions?

JPanel buttonPanel = new JPanel();
buttonPanel.add(new JButton("A button"));
buttonPanel.add(new JLabel("Some description for the awesome table below "));
buttonPanel.add(new JButton("another button"));
JScrollPane tablePanel = new JScrollPane(table);
JPanel container = new JPanel();
container.add(buttonPanel,BorderLayout.NORTH);
container.add(tablePanel,BorderLayout.SOUTH);
contentHolder.addTab("Preview", container);
//contentHolder.validate(); <- NO good
//contentHolder.repaint(); <- --"---
}
JPanel uses FlowLayout (implemented in API, acceptiong only PreferredSize, by default isn't resizable), correct output as is demonstrated in attn image, you have to change default LayoutManager for JPanel to BorderLayout, then code lines
.
container.add(buttonPanel,BorderLayout.NORTH);
container.add(tablePanel,BorderLayout.SOUTH);
will expands JComponents and can be works as you expecting, but I think tablePanel should be placed in CENTER area
EDIT:
import java.awt.BorderLayout;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
public class MyFrame extends JFrame {
private JPanel panel1;
private JTabbedPane tabs;
private JButton runButton;
private JFrame frame = new JFrame();
private String[] columnNames = {"Nama", "Nim", "IP", "Hapus Baris ke"};
private Object[][] data = {
{"igor", "B01_125-358", "1.124.01.125", true},
{"lenka", "B21_002-242", "21.124.01.002", true},
{"peter", "B99_001-358", "99.124.01.001", false},
{"zuza", "B12_100-242", "12.124.01.100", true},
{"jozo", "BUS_011-358", "99.124.01.011", false},
{"nora", "B09_154-358", "9.124.01.154", false},
{"xantipa", "B01_001-358", "1.124.01.001", false},};
private DefaultTableModel model = new DefaultTableModel(data, columnNames) {
private static final long serialVersionUID = 1L;
#Override
public boolean isCellEditable(int row, int column) {
switch (column) {
case 3:
return true;
default:
return false;
}
}
#Override
public Class getColumnClass(int column) {
return getValueAt(0, column).getClass();
}
};
public MyFrame() {
tabs = new JTabbedPane();
panel1 = new JPanel();
runButton = new JButton("go!");
runButton.addActionListener(new java.awt.event.ActionListener() {
#Override
public void actionPerformed(java.awt.event.ActionEvent evt) {
//
}
});
panel1.add(runButton);
tabs.addTab("first tab", panel1);
JTable table = new JTable(model);
JPanel buttonPanel = new JPanel();
buttonPanel.add(new JButton("A button"));
buttonPanel.add(new JLabel("Some description for the awesome table below "));
buttonPanel.add(new JButton("another button"));
JScrollPane tablePanel = new JScrollPane(table);
JPanel container = new JPanel();
container.setLayout(new BorderLayout());
container.add(buttonPanel, BorderLayout.NORTH);
container.add(tablePanel, BorderLayout.CENTER);
tabs.addTab("Preview", container);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(tabs);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
MyFrame frame = new MyFrame();
}
});
}
}
EDIT 2nd. e.g.
from code (included your idea about to fill data to model)
import java.awt.BorderLayout;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;
public class MyFrame extends JFrame {
private JPanel panel1;
private JTabbedPane tabs;
private JButton runButton;
private JFrame frame = new JFrame();
private String[] columnNames = {"Nama", "Nim", "IP", "Hapus Baris ke"};
private Object[][] data = {
{"igor", "B01_125-358", "1.124.01.125", "true"},
{"lenka", "B21_002-242", "21.124.01.002", "true"},
{"peter", "B99_001-358", "99.124.01.001", "false"},
{"zuza", "B12_100-242", "12.124.01.100", "true"},
{"jozo", "BUS_011-358", "99.124.01.011", "false"},
{"nora", "B09_154-358", "9.124.01.154", "false"},
{"xantipa", "B01_001-358", "1.124.01.001", "false"},};
private DefaultTableModel model = new DefaultTableModel(data, columnNames) {
private static final long serialVersionUID = 1L;
#Override
public boolean isCellEditable(int row, int column) {
switch (column) {
case 3:
return true;
default:
return false;
}
}
#Override
public Class getColumnClass(int column) {
return getValueAt(0, column).getClass();
}
};
public MyFrame() {
tabs = new JTabbedPane();
panel1 = new JPanel();
runButton = new JButton("go!");
runButton.addActionListener(new java.awt.event.ActionListener() {
#Override
public void actionPerformed(java.awt.event.ActionEvent evt) {
List<String[]> data = new LinkedList<String[]>();
for (int i = 1; i < 10; i++) {
data.add(new String[]{"entry1", "value1", "value2", "value3"});
}
for (String[] datarow : data) {
model.addRow(Arrays.copyOf(datarow, datarow.length, Object[].class));
}
}
});
panel1.add(runButton);
tabs.addTab("first tab", panel1);
JTable table = new JTable(model);
JPanel buttonPanel = new JPanel();
buttonPanel.add(new JButton("A button"));
buttonPanel.add(new JLabel("Some description for the awesome table below "));
buttonPanel.add(new JButton("another button"));
JScrollPane tablePanel = new JScrollPane(table);
JPanel container = new JPanel();
container.setLayout(new BorderLayout());
container.add(buttonPanel, BorderLayout.NORTH);
container.add(tablePanel, BorderLayout.CENTER);
tabs.addTab("Preview", container);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(tabs);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String args[]) {
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
MyFrame frame = new MyFrame();
}
});
}
}

Following the footsteps of mKorbel I ended up doing some debugging. I am providing it here in case others run into the same problem.
It felt quite odd that the table looked OK when the underlying DataModel was supplied a data matrix upon initialisation
private DefaultTableModel model = new DefaultTableModel(data, columnNames)
but it would not show up properly when created with the empty constructor
private DefaultTableModel model = new DefaultTableModel()
and adding rows later with model.addRow(Object[] row);
I started look through the source code, and it turns out with the empty constructor the number of rows and columns for the model (private fields) is initiated to 0 and not updated properly afterwards. I noticed this while debugging since my tables had the dimension of 1370 x 0, which of course does not display properly.
Since I do not want to hardcode the number of rows/cols in advance the best course of action was to convert my "rows" to a matrix and provide the data to the model via constructor (much like mKorbel did). Here comes the fun part, if you want to supply the data then you need to supply the column names as well. THe fact that you have to have column names is counter-intuitive (IMHO), what happens if you dont have/need headers? The data is already in a table form, so I dont understand why column names is so important.
At any rate the following code renders the table at least:
String[] colNames = new String[data[1].length];
for(int i=0; i<colNames.length; i++)
colNames[i] = "C" + i;
DefaultTableModel model = new DefaultTableModel(data,colNames){
#Override
public boolean isCellEditable(int row, int column){
return false;
}};
I am accepting this because it points to the origin of the problem, but I would not be able to pinpoint the problem without mKorbel's answer, so give the upvote to his/her answer :)

JTable autoscroll to the bottom in Java

I would like the JTable to autoscroll to the bottom whenever I add a new column and show the last 10 rows. However, I have the option of scrolling to anywhere I want (mouse listener?). Do you know how to do that? Here's the code I have so far. It builds a JTable and adds a new row for every mouse click on the JButton.
import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTable;
import javax.swing.SwingUtilities;
import javax.swing.table.DefaultTableModel;
public class sampleGUI extends JFrame implements ActionListener {
private JButton incrementButton;
private JTable table;
private DefaultTableModel model;
private int count;
private JScrollPane scroll;
public sampleGUI() {
JFrame frame = new JFrame("sample frame");
frame.setLayout(new BorderLayout());
incrementButton = new JButton("Increase the count!");
model = new DefaultTableModel();
model.addColumn("column 1");
table = new JTable(model);
frame.add(incrementButton, BorderLayout.NORTH);
scroll = new JScrollPane(table)
frame.add(scroll, BorderLayout.CENTER);
count = 0;
incrementButton.addActionListener(this);
frame.pack();
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
#Override
public synchronized void actionPerformed(ActionEvent e) {
if (e.getSource() == incrementButton) {
count++;
model.addRow(new Object[] { count });
}
}
public static void main(final String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
sampleGUI gui = new sampleGUI();
}
});
}
}
Thanks!

Required to change selection in JTable, add code line
table.changeSelection(table.getRowCount() - 1, 0, false, false);
to
public (synchronized) void actionPerformed(ActionEvent e) {

I would like the JTable to autoscroll to the bottom whenever I add a new column
I assume you mean scroll to the bottom when you add a new row?
model.addRow(new Object[] { count });
table.scrollRectToVisible(...);

You forget add JScrollPane to the table :
//...
frame.add(new JScrollPane(table), BorderLayout.CENTER);
//...
and don't forget
import javax.swing.JScrollPane;

After updating JComboBox, how to refresh length of box

I am trying to create a way to update a JComboBox so that when the user enters something into the text field, some code will process the entry and update the JComboBox accordingly.The one issue that I am having is I can update the JComboBox, but the first time it is opened, the box has not refresh the length of the options in it and as seen in the code below it displays extra white space. I do not know if there is a better different way to do this, but this is what I came up with.
Thanks for the help,
Dan
import java.awt.event.*;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class Catch{
public static JComboBox dropDown;
public static String dropDownOptions[] = {
"Choose",
"1",
"2",
"3"};
public static void main(String[] args) {
dropDown = new JComboBox(dropDownOptions);
final JTextField Update = new JTextField("Update", 10);
final JFrame frame = new JFrame("Subnet Calculator");
final JPanel panel = new JPanel();
frame.setSize(315,430);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
Update.addFocusListener(new FocusListener(){
public void focusGained(FocusEvent arg0) {
}
public void focusLost(FocusEvent arg0) {
dropDown.removeAllItems();
dropDown.insertItemAt("0", 0);
dropDown.insertItemAt("1", 1);
dropDown.setSelectedIndex(0);
}
});
panel.add(Update);
panel.add(dropDown);
frame.getContentPane().add(panel);
frame.setVisible(true);
Update.requestFocus();
Update.selectAll();
}
}

1) JTextField listening for ENTER key from ActionListener
2) remove FocusListener
3) example about add new Item as last Item from JTextField to the JList, only you have to modify for JComboBox and add method insertItemAt() correctly
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ListBottom2 {
private static final long serialVersionUID = 1L;
private JFrame frame = new JFrame();
private DefaultListModel model = new DefaultListModel();
private JList list = new JList(model);
private JTextField textField = new JTextField("Use Enter to Add");
private JPanel panel = new JPanel(new BorderLayout());
public ListBottom2() {
model.addElement("First");
list.setVisibleRowCount(5);
panel.setBackground(list.getBackground());
panel.add(list, BorderLayout.SOUTH);
JScrollPane scrollPane = new JScrollPane(panel);
scrollPane.setPreferredSize(new Dimension(200, 100));
frame.add(scrollPane);
frame.add(textField, BorderLayout.NORTH);
textField.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JTextField textField = (JTextField) e.getSource();
DefaultListModel model = (DefaultListModel) list.getModel();
model.addElement(textField.getText());
int size = model.getSize() - 1;
list.scrollRectToVisible(list.getCellBounds(size, size));
textField.setText("");
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
ListBottom2 frame = new ListBottom2();
}
});
}
}

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