We Keep Coding

How am I to run my GUI? Or to be more exact, what do I put in my main?

public class StatsGUI extends JFrame implements ActionListener {
JLabel label;
JLabel label2;
JTextField input;
JTextField output;
JButton getButton;
JButton exitButton;
public StatsGUI()
{
JPanel panel = new JPanel();
label = new JLabel("Enter number");
panel.add(label);
input = new JTextField(10);
input.addActionListener(this);
panel.add(input);
label2 = new JLabel("Statistics");
output = new JTextField(10);
output.setEditable(false);
panel.add(output);
getButton = new JButton("Go");
getButton.addActionListener(this);
panel.add(getButton);
exitButton = new JButton("Exit");
exitButton.addActionListener(this);
panel.add(exitButton);
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == exitButton)
{
System.exit(0);
}
else
{
String text = input.getText();
output.setText(text + "COUNTER");
}
}
public static void main(String[] args)
{
}
This is my simple GUI program. I have placed all buttons and other gadgets within the constructor. However, I am not sure what I should be putting inside my main in order to get my GUI to actually show up. I am sure I am missing something incredibly simple here however I am not sure what. Help would be much appreciated.

You are not that far from getting things to work. Just a few things to know:
Your UI should be started on the Event dispatching thread (EDT)
You actually need to add your panels/components to your frame
You need to pack() your Window/Frame
You need to make it visible
(Design stuff, optional but when you are at it, why not just fix that as well), no need to extend JFrame, so let's just drop that.
So eventually, taking these advices into consideration leads you to something like this:
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;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class StatsGUI implements ActionListener {
JLabel label;
JLabel label2;
JTextField input;
JTextField output;
JButton getButton;
JButton exitButton;
#Override
public void actionPerformed(ActionEvent e) {
if (e.getSource() == exitButton) {
System.exit(0);
} else {
String text = input.getText();
output.setText(text + "COUNTER");
}
}
public void initUI() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
label = new JLabel("Enter number");
panel.add(label);
input = new JTextField(10);
input.addActionListener(this);
panel.add(input);
label2 = new JLabel("Statistics");
output = new JTextField(10);
output.setEditable(false);
panel.add(output);
getButton = new JButton("Go");
getButton.addActionListener(this);
panel.add(getButton);
exitButton = new JButton("Exit");
exitButton.addActionListener(this);
panel.add(exitButton);
frame.add(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
new StatsGUI().initUI();
}
});
}
}

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
class StatsGUI extends JFrame implements ActionListener {
JLabel label;
JLabel label2;
JTextField input;
JTextField output;
JButton getButton;
JButton exitButton;
public StatsGUI()
{
JPanel panel = new JPanel();
label = new JLabel("Enter number");
panel.add(label);
input = new JTextField(10);
input.addActionListener(this);
panel.add(input);
label2 = new JLabel("Statistics");
output = new JTextField(10);
output.setEditable(false);
panel.add(output);
getButton = new JButton("Go");
getButton.addActionListener(this);
panel.add(getButton);
exitButton = new JButton("Exit");
exitButton.addActionListener(this);
panel.add(exitButton);
add(panel);
}
public void actionPerformed(ActionEvent e)
{
if(e.getSource() == exitButton)
{
System.exit(0);
}
else
{
String text = input.getText();
output.setText(text + "COUNTER");
}
}
public static void main(String[] args)
{
StatsGUI s= new StatsGUI();
s.setVisible(true);
s.setSize(1000,1000);
}
}
You are not calling a contructor .call costructor like 'StatsGUI s= new StatsGUI();' or 'new StatsGUI();' .

JButton - How to connect?

I found this code online and modified it and it stopped working. I'm thinking it has something to do with when I added the Jpanel but what I am doing works best with a JPanel. How do I make it that the events in the action performed if statements work?
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.*;
import javax.swing.*;
public class GUI extends JFrame implements ActionListener {
static JPanel panel = new JPanel(new GridLayout(5, 5, 1, 1));
public GUI() {
setDefaultCloseOperation(EXIT_ON_CLOSE);
//setSize(100, 100);
//setLocation(100, 100);
//Button 1
JButton button1 = new JButton("1");
button1.addActionListener(this);
panel.add(button1);
//Button 2
JButton button2 = new JButton("2");
button2.addActionListener(this);
panel.add(button2);
//Button 3
JButton button3 = new JButton("3");
button3.addActionListener(this);
panel.add(button3);
//Button 2
JButton button4 = new JButton("4");
button4.addActionListener(this);
panel.add(button4);
//Button 2
JButton button5 = new JButton("5");
button5.addActionListener(this);
panel.add(button5);
//Button 2
JButton button6 = new JButton("6");
button6.addActionListener(this);
panel.add(button6);
//Button 2
JButton button7 = new JButton("7");
button7.addActionListener(this);
panel.add(button7);
//Button 2
JButton button8 = new JButton("8");
button8.addActionListener(this);
panel.add(button8);
//Button 2
JButton button9 = new JButton("9");
button9.addActionListener(this);
panel.add(button9);
panel.setVisible(true);
}
public static void main(String[] args) {
new GUI();
JFrame f = new JFrame("Calc");
f.setContentPane(panel);
f.setSize(1000, 1000);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
ArrayList numbers = new ArrayList();
#Override
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if (command.equals("button1")) {
myMethod();
numbers.add(1);
System.out.println("1");
}
if (command.equals("button1")) {
numbers.add(2);
System.out.println("2");
}
}
public void myMethod() {
JOptionPane.showMessageDialog(this, "Hello, World!!!!!");
System.out.println("Hey");
}
}

You need to change the part actionPerformed as:
#Override
public void actionPerformed(ActionEvent e) {
String command = e.getActionCommand();
if (command.equals("1")) {
myMethod();
numbers.add(1);
System.out.println("1");
}
if (command.equals("2")) {
numbers.add(2);
System.out.println("2");
}
}
Here, when a button is clicked, your e.getActionCommand() will give the constructor string. i.e. "1", "2" ,"3" and so on
reference

I put comments in code, but the first thing you should do is to read official tutorials. How to use Buttons
public class GUI /*extends JFrame implements ActionListener*/ {
//don't extend JFrame is you don't have too neither implement ActionListener in top-container classes that breaks single responsability principle
private JPanel panel = new JPanel(new GridLayout(5, 5, 1, 1)); // why static??
public JPanel getPanel(){
return panel;
}
public GUI() {
//i use anonymous classes for this, then you don't have to use if-else
//Button 1
JButton button1 = new JButton("1");
button1.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent evt){
myMethod();
numbers.add(1);
System.out.println("1");
}
});
panel.add(button1);
//Button 2
JButton button2 = new JButton("2");
button2.addActionListener(new ActionListener(){
#Override
public void actionPerformed(ActionEvent evt){
//put here logic for button2
}
});
panel.add(button2);
//and goo on with other buttons
//panel.setVisible(true); you don't need to call this!!
}
/**
* Create the GUI and show it. For thread safety,
* this method should be invoked from the
* event-dispatching thread.
*/
private static void createAndShowGUI() {
//Create and set up the window.
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
GUI gui = new GUI();
frame.add(gui.getPanel());
//Display the window.
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
//Schedule a job for the event-dispatching thread:
//creating and showing this application's GUI.
javax.swing.SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGUI();
}
});
}
private List<Integer> numbers = new ArrayList<>();//use generics!
public void myMethod() {
JOptionPane.showMessageDialog(this, "Hello, World!!!!!");
System.out.println("Hey");
}
}

Use If-Else statement in SubmitListener

Trying to develop a GUI, but I've hit a snag:
I am using a submit button, which will look at a txtEnter field. If the user types "yes" in the txtEnter field and clicks submit, it will execute a shell script. If the user types "no" there will be no action. I know the command to run shell script is Runtime.getRuntime().exec(myShellScript);
How I can use an if-else statement in the SubmitListner to check for the user's input?
import javax.swing.*; import javax.swing.event.DocumentListener;import java.awt.*;import java.awt.event.ActionEvent;import java.awt.event.ActionListener;public class Executer private JLabel lblCommand;
private JTextField txtEnter;
private JButton btNext, btPrevious, btSubmit;
private JPanel panel;
public static void main(String[] args) {
new Executer();
}
public Executer() {
JFrame frame = new JFrame("Script Executer");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500,300);
frame.setVisible(true);
myPanel();
Text();
Fields();
Buttons();
frame.add(panel);
frame.setVisible(true);
}
public void myPanel() {
panel = new JPanel();
panel.setLayout(null);
}
public void Text(){
lblCommand = new JLabel("Enter Here");
lblCommand.setBounds(145, 100, 150, 20);
Font styleOne = new Font("Arial", Font.BOLD, 13);
lblCommand.setFont(styleOne);
panel.add(lblCommand);
}
public void Fields () {
txtEnter = new JTextField();
txtEnter.setBounds(230, 100, 120, 20);
panel.add(txtEnter);
}
public void Buttons() {
btNext = new JButton ("Next");
btNext.setBounds(300,215,100,20);
panel.add(btNext);
btPrevious = new JButton ("Previous");
btPrevious.setBounds(190,215,100,20);
panel.add(btPrevious);
btSubmit = new JButton("Submit");
btSubmit.setBounds(80,215,100,20);
panel.add(btSubmit);
}
class SubmitListener implements ActionListener {
public void actionPerformed(ActionEvent e) {
}}}

You have to assign your Actionlistener to your button:
btSubmit = new JButton();
btSubmit.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
// here the click happend so you can check your Textfield
String userEntered = txtEnter.getText();
if(userEntered.equalsIgnoreCase("yes"))
{
//run your script
}
}
});

Generating non-repeating random methods in GUI

I've been spending so long looking at my computer monitor because I really don't know what to do to prevent the frames on my program on appearing simultaneously when I click the Start button.
Here's my main class:
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.Random;
import javax.swing.*;
public class PopQuizDemo {
public static void main (String args[]){
PopQuizDemo();
}
public static void PopQuizDemo(){
final SimpleFrame frame = new SimpleFrame();
final JPanel main = new JPanel();
main.setSize(400,75);
main.setLayout(new GridLayout(3,1));
frame.add(main);
JLabel l1 = new JLabel("Welcome to POP Quiz!");
main.add(l1);
JLabel l2 = new JLabel("Enter your name:");
main.add(l2);
final JTextField name = new JTextField ();
main.add(name);
final JPanel panel = new JPanel();
panel.setSize(400,50);
panel.setLocation(0,225);
frame.add(panel);
JButton start = new JButton ("Start");
panel.add(start);
frame.setVisible(true);
start.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
randomize();
}
});
}
public static void randomize(){
Questions q = new Questions();
int a=0;
Random randnum = new Random (System.currentTimeMillis());
java.util.HashSet<Integer> myset = new java.util.HashSet<>();
for (int count = 1; count <= 3; count++){
while (true) {
a = randnum.nextInt (3);
if(!myset.contains(a)) { myset.add(new Integer(a)); break;}
}
if(a==0){
q.one();
}
else if(a==1){
q.two();
}
else if(a==2){
q.three();
}
else{
break;
}
}
}
}
And here is the class Question where I get the methods one(), two(), and three():
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JPanel;
public class Questions {
public static void one(){
final SimpleFrame frame = new SimpleFrame();
JPanel p1 = new JPanel();
p1.setSize(400,100);
frame.add(p1);
JLabel qu1 = new JLabel();
qu1.setText("In computers, what is the smallest and basic unit of");
JLabel qu2 = new JLabel();
qu2.setText("information storage?");
p1.add(qu1);
p1.add(qu2);
JPanel p2 = new JPanel();
p2.setSize(400,175);
p2.setLocation(0,100);
p2.setLayout(new GridLayout(2,4));
frame.add(p2);
JButton a = new JButton("a. Bit");
p2.add(a);
JButton b = new JButton("b. Byte");
p2.add(b);
JButton c = new JButton("c. Data");
p2.add(c);
JButton d = new JButton("d. Newton");
p2.add(d);
frame.setVisible(true);
final PopQuizDemo demo = new PopQuizDemo();
a.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
c.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
d.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
}//end of method
public static void two(){
final SimpleFrame frame = new SimpleFrame();
JPanel p1 = new JPanel();
p1.setSize(400,100);
frame.add(p1);
JLabel qu1 = new JLabel();
qu1.setText("Machine language is also known as __________.");
p1.add(qu1);
JPanel p2 = new JPanel();
p2.setSize(400,175);
p2.setLocation(0,100);
p2.setLayout(new GridLayout(2,4));
frame.add(p2);
JButton a = new JButton("a. Low level language");
p2.add(a);
JButton b = new JButton("b. Assembly language");
p2.add(b);
JButton c = new JButton("c. High level language");
p2.add(c);
JButton d = new JButton("d. Source code");
p2.add(d);
frame.setVisible(true);
final PopQuizDemo demo = new PopQuizDemo();
a.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
c.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
d.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
}//end of method
public static void three(){
final SimpleFrame frame = new SimpleFrame();
JPanel p1 = new JPanel();
p1.setSize(400,100);
frame.add(p1);
JLabel qu1 = new JLabel();
qu1.setText("What is the shortcut key of printing a document for");
JLabel qu2 = new JLabel();
qu2.setText("computers using Windows?");
p1.add(qu1);
p1.add(qu2);
JPanel p2 = new JPanel();
p2.setSize(400,175);
p2.setLocation(0,100);
p2.setLayout(new GridLayout(2,4));
frame.add(p2);
JButton a = new JButton("a. Ctrl + P");
p2.add(a);
JButton b = new JButton("b. Shift + P");
p2.add(b);
JButton c = new JButton("c. Shift + PP");
p2.add(c);
JButton d = new JButton("d. Alt + P");
p2.add(d);
frame.setVisible(true);
final PopQuizDemo demo = new PopQuizDemo();
a.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
b.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
c.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
d.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
frame.setVisible(false);
demo.randomize();
}
});
}//end of method
}
The only problem here is that the when I call the method randomize() in the action listener in the Start button, it shows all the frames. Yes, they are not repeating but it shows simultaneously. I don't know where the problem is. Is it with the method randomize, the looping, the questions? Can someone help me? Please? Big thanks.
PS:
This is the class SimpleFrame
import javax.swing.JFrame;
public class SimpleFrame extends JFrame{
public SimpleFrame(){
setSize(400,300);
setTitle("Pop Quiz!");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(null);
setResizable(false);
}
}

You can use model dialog to show one after another using a for loop as show below:
public static void main(String[] args) {
JFrame m = new JFrame("Hello");
m.setSize(200,200);
m.setVisible(true);
for(int i=0;i<3;i++) {
JDialog dlg = new JDialog(m,"Dialog",true);
dlg.setSize(100,100);
dlg.show();
}
}

How do I hide the current JPanel and show a new one with a button in Java?

I unfortunately have to use multiple windows in this program and I don't think CardLayout is going to work because I can't have any buttons constant between the different layouts. So I'm trying to code a button to hide the present JPanel (thePanel) and show a new one (thePlacebo).
I'm trying to hide thePanel in an ActionListener like this:
frame.getContentPane().remove(thePanel);
I thought this would work, but it just freezes my program as soon as I hit the button.
Here's a chunk of the code for context:
public class Reflexology1 extends JFrame{
JButton button1, button2;
JButton movingButton;
JTextArea textArea1;
int buttonAClicked, buttonDClicked;
private long _openTime = 0;
private long _closeTime = 0;
JPanel thePanel = new JPanel();
JPanel thePlacebo = new JPanel();
final JFrame frame = new JFrame("Reflexology");
public static void main(String[] args){
new Reflexology1();
}
public Reflexology1(){
frame.setSize(600, 475);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("Reflexology 1.0");
frame.setResizable(false);
button1 = new JButton("Accept");
button2 = new JButton("Decline");
movingButton = new JButton("Click Me");
ListenForAcceptButton lForAButton = new ListenForAcceptButton();
ListenForDeclineButton lForDButton = new ListenForDeclineButton();
button1.addActionListener(lForAButton);
button2.addActionListener(lForDButton);
//movingButton.addActionListener(lForMButton);
JTextArea textArea1 = new JTextArea(24, 50);
textArea1.setText("Tracking Events\n");
textArea1.setLineWrap(true);
textArea1.setWrapStyleWord(true);
textArea1.setSize(15, 50);
FileReader reader = null;
try {
reader = new FileReader("EULA.txt");
textArea1.read(reader, "EULA.txt");
} catch (IOException exception) {
System.err.println("Problem loading file");
exception.printStackTrace();
} finally {
if (reader != null) {
try {
reader.close();
} catch (IOException exception) {
System.err.println("Error closing reader");
exception.printStackTrace();
}
}
}
JScrollPane scrollBar1 = new JScrollPane(textArea1, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
AdjustmentListener listener = new MyAdjustmentListener();
thePanel.add(scrollBar1);
thePanel.add(button1);
thePanel.add(button2);
thePlacebo.add(movingButton);
frame.add(thePanel);
ListenForWindow lForWindow = new ListenForWindow();
frame.addWindowListener(lForWindow);
frame.setVisible(true);
}
// Implement listeners
private class ListenForAcceptButton implements ActionListener{
public void actionPerformed(ActionEvent e){
if (e.getSource() == button1){
Calendar ClCDateTime = Calendar.getInstance();
System.out.println(ClCDateTime.getTimeInMillis() - _openTime);
_closeTime = ClCDateTime.getTimeInMillis() - _openTime;
frame.getContentPane().remove(thePanel);
}
}
}
Does anybody know what I might be doing wrong?

After removing components from a container, it goes into the invalidate state. To bring it back to the valid state you have to revalidate and repaint that. In your case you are directly adding/removing components from JFrame so depending on the Java version you can do this :
frame.revalidate(); // For Java 1.7 or above
frame.getContentPane().validate(); // For Java 1.6 or below
frame.repaint();
Here is one working example for your help :
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Assignment
{
private JFrame frame;
private JPanel firstPanel;
private JPanel secondPanel;
private JButton forwardButton;
private JButton backButton;
private void displayGUI()
{
frame = new JFrame("Assignment");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
firstPanel = new JPanel();
firstPanel.setOpaque(true);
firstPanel.setBackground(Color.BLUE);
secondPanel = new JPanel();
secondPanel.setOpaque(true);
secondPanel.setBackground(Color.RED);
forwardButton = new JButton("Forward");
forwardButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
frame.remove(firstPanel);
frame.add(secondPanel);
frame.revalidate(); // For Java 1.7 or above.
// frame.getContentPane().validate(); // For Java 1.6 or below.
frame.repaint();
}
});
backButton = new JButton("Back");
backButton.addActionListener(new ActionListener()
{
#Override
public void actionPerformed(ActionEvent ae)
{
frame.remove(secondPanel);
frame.add(firstPanel);
frame.revalidate(); // For Java 1.7 or above.
// frame.getContentPane().validate(); // For Java 1.6 or below.
frame.repaint();
}
});
firstPanel.add(forwardButton);
secondPanel.add(backButton);
frame.add(firstPanel);
frame.setSize(300, 300);
frame.setLocationByPlatform(true);
frame.setVisible(true);
}
public static void main(String... args)
{
SwingUtilities.invokeLater(new Runnable()
{
#Override
public void run()
{
new Assignment().displayGUI();
}
});
}
}

correct way could be (only) by using CardLayout
otherwise have to remove JPanel from container and to call (as last code line and call only one times after all changes for container are done)
.
myJPanelsContainer#revalidate(); // in Java6 for JFrame validate()
myJPanelsContainer#repaint();