We Keep Coding

How to connect method from another class to actionListener?

I'm trying to finish my project about searching graphs, where one of the functions is input (vertex and edges) from user.
I already have a method for this in another class, but now I need to put it into GUI.
I've already tried many of tutorials, but nothing worked. Can somebody help me, how to put the method getInputFromCommand to gui?
I've already tried to copy the method into the GUI, but there was problem with the "return g" because of the void result type, I've tried just to call the method, (I know.. stupid) but it didn't work either.
package Process;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;
public class FindIslands {
String message = "";
int V;
LinkedList<Integer>[] adjListArray;
static LinkedList<String> nodeList = new LinkedList<String>();
// constructor
FindIslands(int V) {
this.V = V;
adjListArray = new LinkedList[V];
for (int i = 0; i < V; i++) {
adjListArray[i] = new LinkedList<Integer>();
}
}
void addEdge(int src, int dest) {
adjListArray[src].add(dest);
adjListArray[dest].add(src);
}
void DFSUtil(int v, boolean[] visited) {
visited[v] = true;
message += getValue(v) + " ";
// System.out.print(getValue(v) + " ");
for (int x : adjListArray[v]) {
if (!visited[x]) {
DFSUtil(x, visited);
}
}
}
void connectedComponents() {
boolean[] visited = new boolean[V];
int count = 0;
message = "";
for (int v = 0; v < V; ++v) {
if (!visited[v]) {
DFSUtil(v, visited);
message += "\n";
// System.out.println();
count++;
}
}
System.out.println("" + count);
System.out.println("");
System.out.println("Vypis ostrovu: ");
String W[] = message.split("\n");
Arrays.sort(W, new java.util.Comparator<String>() {
#Override
public int compare(String s1, String s2) {
// TODO: Argument validation (nullity, length)
return s1.length() - s2.length();// comparison
}
});
for (String string : W) {
System.out.println(string);
}
}
public static void main(String[] args) {
FindIslands g = null; //
String csvFile = "nodefile.txt";
BufferedReader br = null;
String line = "";
int emptyLine = 0;
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
if (line.equals("")) {
emptyLine = 1;
// System.out.println("found blank line");
}
if (emptyLine == 0) {
// System.out.println(line);
nodeList.add(line);
} else if (line.isEmpty()) {
g = new FindIslands(nodeList.size());
} else {
String[] temp = line.split(",");
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
}
} catch (FileNotFoundException e) {
System.out.println("Soubor nenalezen, zadejte data v danem formatu");
g = getInputFromCommand();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Pocet ostrovu");
if (g != null) {
g.connectedComponents();
}
}
public static int getIndex(String str) {
return nodeList.indexOf(str);
}
public static String getValue(int index) {
return nodeList.get(index);
}
public static FindIslands getInputFromCommand() {
FindIslands g = null;
BufferedReader br = null;
String line = "";
int emptyLine = 0;
Scanner scanner = new Scanner(System.in);
line = scanner.nextLine();
while (!line.equals("")) {
if (line.equals("--gui")) {
Guicko gui = new Guicko();
gui.setVisible(true);
} else
nodeList.add(line);
line = scanner.nextLine();
}
g = new FindIslands(nodeList.size());
line = scanner.nextLine();
while (!line.equals("")) {
String[] temp = line.split(",");
if (temp.length != 2) {
System.out.println("spatny format zadanych dat, prosim zkuste znovu");
} else {
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
line = scanner.nextLine();
}
return g;
}
}
Where important is the last method "getInputFromCommand()"
and... gui
package Process;
import javax.swing.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.util.Scanner;
public class Guicko extends JFrame {
private JButton štartButton;
private JPanel panel;
private JTextField textField2;
private JTextArea textArea1;
public Guicko() {
add(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setTitle("Zadej hodnoty");
setSize(500, 400);
textField2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
FindIslands.getInputFromCommand();
}
});
štartButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String str = "asd";
FindIslands g = null;
g.connectedComponents();
textArea1.setText(str);
}
});
}
public static void main (String args[]){
Guicko gui = new Guicko();
gui.setVisible(true);
}
}

I'm sure there are many correct ways this code can be fixed, but in IMHO, your Guicko class needs to have a FindIslands class member, and I think you need to move some stuff from FindIslands.main() into Guicko.main() or some other method.
Then your "Action Listener" inner classes' actionPerformed methods just delegate to the methods in the FindIslands member instance, like this
....
private FindIslands fi;
public Guicko() {
....
textField2.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
fi = FindIslands.getInputFromCommand();
}
});
startButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String comps = fi.connectedComponents();// method needs to return a string
textArea1.setText(comps);
}
});
}

The whole idea of seperating GUI from domain is to make changes easily. GUI has knowledge of the domain but domain has no knowledge about the GUI. We can use an interface to seperate them, in that case, Domain says , i don't care who implements this interface but whoever implements this interface will get response and can work with me.
So , If we create a new GUI, we can let it implements that interface and the same domain will work with that GUI.
There are many mistakes but in order to make it work and to show you an example i did few changes.
public class Guicko extends JFrame implements PropertyChangeListener{
private JButton štartButton;
private JPanel panel;
private JTextField textField2;
private JTextArea textArea1;
private FindIslands land;
private JTextField textField;
private JButton button;
public Guicko() {
JPanel panel = new JPanel();
super.getContentPane().setLayout(new GridLayout());
//For each gui, there should be one land.
this.setLand(new FindIslands(100));
//Subscribe to the domain so that you can get update if something change in domain.
this.getLand().subscribe(this);
//Dummy buttons are fields(need too initiate first)
textField2 = new JTextField("",30);
štartButton = new JButton();
textField = new JTextField("",30);
button = new JButton();
button.setPreferredSize(new Dimension(100, 40));
button.setText("Get input from Domain");
štartButton.setPreferredSize(new Dimension(100, 40));
textField.setEditable(false);
štartButton.setText("Start");
panel.add(textField2);
panel.add(štartButton);
panel.add(textField);
panel.add(button);
add(panel);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
setTitle("Zadej hodnoty");
setSize(500, 400);
//When you type something in , then this function will send it to domain(i mean to function : getInputFromCommand();).
this.addListerToField(štartButton,this.getLand(),textField2);
//Now the second case, suppose you press a button and want something to show up in textfield. In that case , this function will do work.
this.addListerToSecondField(button,this.getLand(),textField);
}
//Here i can catch the events from the domain.
#Override
public void propertyChange(PropertyChangeEvent e) {
if(e.getPropertyName().equals("String changed")) {
this.getTextField().setText((String) e.getNewValue());
}
}
private void addListerToSecondField(JButton button, FindIslands land, JTextField field) {
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
land.requireArgumentsForField();
}
});
}
private void addListerToField(JButton štartButton, FindIslands land, JTextField field) {
štartButton.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
land.getInputFromCommand(field.getText());
}
});
}
public static void main (String args[]){
Guicko gui = new Guicko();
gui.setVisible(true);
}
public FindIslands getLand() {
return land;
}
public void setLand(FindIslands land) {
this.land = land;
}
public JTextField getTextField() {
return textField;
}
public void setTextField(JTextField textField) {
this.textField = textField;
}
public JButton getButton() {
return button;
}
public void setButton(JButton button) {
this.button = button;
}
Here is the second class. Run it and try to get feeling for it how it works.
public class FindIslands {
String message = "";
int V;
LinkedList<Integer>[] adjListArray;
static LinkedList<String> nodeList = new LinkedList<String>();
// constructor
FindIslands(int V) {
this.V = V;
//initialize the list
this.setListeners(new ArrayList<>());
adjListArray = new LinkedList[V];
for (int i = 0; i < V; i++) {
adjListArray[i] = new LinkedList<Integer>();
}
}
void addEdge(int src, int dest) {
adjListArray[src].add(dest);
adjListArray[dest].add(src);
}
void DFSUtil(int v, boolean[] visited) {
visited[v] = true;
message += getValue(v) + " ";
// System.out.print(getValue(v) + " ");
for (int x : adjListArray[v]) {
if (!visited[x]) {
DFSUtil(x, visited);
}
}
}
void connectedComponents() {
boolean[] visited = new boolean[V];
int count = 0;
message = "";
for (int v = 0; v < V; ++v) {
if (!visited[v]) {
DFSUtil(v, visited);
message += "\n";
// System.out.println();
count++;
}
}
System.out.println("" + count);
System.out.println("");
System.out.println("Vypis ostrovu: ");
String W[] = message.split("\n");
Arrays.sort(W, new java.util.Comparator<String>() {
#Override
public int compare(String s1, String s2) {
// TODO: Argument validation (nullity, length)
return s1.length() - s2.length();// comparison
}
});
for (String string : W) {
System.out.println(string);
}
}
//You need only one main class, not two.----------------------------
/**
public static void main(String[] args) {
FindIslands g = null; //
String csvFile = "nodefile.txt";
BufferedReader br = null;
String line = "";
int emptyLine = 0;
try {
br = new BufferedReader(new FileReader(csvFile));
while ((line = br.readLine()) != null) {
if (line.equals("")) {
emptyLine = 1;
// System.out.println("found blank line");
}
if (emptyLine == 0) {
// System.out.println(line);
nodeList.add(line);
} else if (line.isEmpty()) {
g = new FindIslands(nodeList.size());
} else {
String[] temp = line.split(",");
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
}
} catch (FileNotFoundException e) {
System.out.println("Soubor nenalezen, zadejte data v danem formatu");
g = getInputFromCommand();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
System.out.println("Pocet ostrovu");
if (g != null) {
g.connectedComponents();
}
}
**/
public static int getIndex(String str) {
return nodeList.indexOf(str);
}
public static String getValue(int index) {
return nodeList.get(index);
}
//Static cases are to be avoided.This is the property of object not class.
public void getInputFromCommand(String string) {
//Here you will recieve a string from the GUI and will be printed in command prompt.You can do whatever you want to do with it.
System.out.println("Recieve string is " + string);
//No idea what you are trying to do.
/** FindIslands g = null;
BufferedReader br = null;
String line = "";
int emptyLine = 0;
Scanner scanner = new Scanner(System.in);
line = scanner.nextLine();
while (!line.equals("")) {
if (line.equals("--gui")) {
Guicko gui = new Guicko();
gui.setVisible(true);
} else
nodeList.add(line);
line = scanner.nextLine();
}
g = new FindIslands(nodeList.size());
line = scanner.nextLine();
while (!line.equals("")) {
String[] temp = line.split(",");
if (temp.length != 2) {
System.out.println("spatny format zadanych dat, prosim zkuste znovu");
} else {
g.addEdge(getIndex(temp[0]), getIndex(temp[1]));
}
line = scanner.nextLine();
}
return line;**/
}
//This function is triggered with second button and you can send data to gui as shown below.
public void requireArgumentsForField() {
//Suppose i want to send following string.
String name = "I don't know";
this.getListeners().stream().forEach(e -> {
// I will catch this in view.
e.propertyChange(new PropertyChangeEvent(this, "String changed", null, name));
});
}
private ArrayList<PropertyChangeListener> listeners;
//Let the objects subscibe. You need this to publish the changes in domain.
public void subscribe(PropertyChangeListener listener) {
this.getListeners().add(listener);
}
public ArrayList<PropertyChangeListener> getListeners() {
return listeners;
}
public void setListeners(ArrayList<PropertyChangeListener> listeners) {
this.listeners = listeners;
}

JFrame freezes when button is pressed and operations from the other Class are ran [duplicate]

I'm writing a program that constantly pings a server. I wrote the code to check it once and put the ping in a JLabel and put it in a method called setPing().
Here is my code
private void formWindowOpened(java.awt.event.WindowEvent evt) {
setPing();
}
That worked but only did it once, so I did:
private void formWindowOpened(java.awt.event.WindowEvent evt) {
for(;;){
setPing();
}
}
But this doesn't even work for the first time.
I didnt put the setPing method because it was too long so here it is:
public String setPing(){
Runtime runtime = Runtime.getRuntime();
try{
Process process = runtime.exec("ping lol.garena.com");
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null) {
int i = 0;
i = line.indexOf("Average");
if(i > 0){
String finalPing = "";
line.toCharArray();
try
{
finalPing = "";
for(int x = i; x < i + 17; x++)
{
finalPing = finalPing + (line.charAt(x));
}
}catch(IndexOutOfBoundsException e)
{
try
{
finalPing = "";
for(int x = i; x < i + 16; x++)
{
finalPing = finalPing + (line.charAt(x));
}
}catch(IndexOutOfBoundsException f)
{
try
{
finalPing = "";
for(int x = i; x < i + 15; x++)
{
finalPing = finalPing + (line.charAt(x));
}
}catch(IndexOutOfBoundsException g){}
}
}
String final1Ping = finalPing.replaceAll("[^0-9]", "");
return final1Ping;
}
}
}catch(IOException e){
}
return "";
}
UPDATE
Just in case this is important, Im using netbeans. I created a form and put this code in the formWindowOpened evt instead of calling it in main:
private void formWindowOpened(java.awt.event.WindowEvent evt) {
ActionListener timerListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
new PingWorker().execute();
}
};
Timer timer = new Timer(1000, timerListener);
timer.start();
jLabel1.setText(label.getText());
timer.stop();
// TODO add your handling code here:
}
class PingWorker extends SwingWorker {
int time;
#Override
protected Object doInBackground() throws Exception {
time = pingTime("lol.garena.com");
return new Integer(time);
}
#Override
protected void done() {
label.setText("" + time);
}
};
public JComponent getUI() {
return label;
}
public static int pingTime(String hostnameOrIP) {
Socket socket = null;
long start = System.currentTimeMillis();
try {
socket = new Socket(hostnameOrIP, 80);
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
}
}
}
long end = System.currentTimeMillis();
return (int) (end - start);
}

Use a Swing Timer for repeating tasks & a SwingWorker for long running tasks. E.G. of both below - it uses a Timer to repeatedly perform a 'long running' task (a ping) in a SwingWorker.
See Concurrency in Swing for more details on the Event Dispatch Thread and doing long running or repeating tasks in a GUI.
This code combines a long running task ('pinging' a server) using SwingWorker invoked from a repeating task (updating the JLabel repeatedly with the times) using a Swing based Timer.
import java.awt.event.*;
import javax.swing.*;
import java.net.Socket;
public class LabelUpdateUsingTimer {
static String hostnameOrIP = "stackoverflow.com";
int delay = 5000;
JLabel label = new JLabel("0000");
LabelUpdateUsingTimer() {
label.setFont(label.getFont().deriveFont(120f));
ActionListener timerListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
new PingWorker().execute();
}
};
Timer timer = new Timer(delay, timerListener);
timer.start();
JOptionPane.showMessageDialog(
null, label, hostnameOrIP, JOptionPane.INFORMATION_MESSAGE);
timer.stop();
}
class PingWorker extends SwingWorker {
int time;
#Override
protected Object doInBackground() throws Exception {
time = pingTime();
return new Integer(time);
}
#Override
protected void done() {
label.setText("" + time);
}
};
public static int pingTime() {
Socket socket = null;
long start = System.currentTimeMillis();
try {
socket = new Socket(hostnameOrIP, 80);
} catch (Exception weTried) {
} finally {
if (socket != null) {
try {
socket.close();
} catch (Exception weTried) {}
}
}
long end = System.currentTimeMillis();
return (int) (end - start);
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
new LabelUpdateUsingTimer();
}
};
SwingUtilities.invokeLater(r);
}
}

You could use a Thread. The problem is you are blocking the main thread, thereby blocking your program. To get around this, start a background Thread to update components repeatedly.
(Note: you need to update GUI components on the EDT, so use SwingUtilities.invokeLater)
(new Thread((new Runnable(){
#Override
public void run(){
while(true){
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run(){
refToJLabel.setText(Math.random());
}
});
}
}
}))).start();

Following method call prevents JLabel from getting visible [duplicate]

I'm writing a program that constantly pings a server. I wrote the code to check it once and put the ping in a JLabel and put it in a method called setPing().
Here is my code
private void formWindowOpened(java.awt.event.WindowEvent evt) {
setPing();
}
That worked but only did it once, so I did:
private void formWindowOpened(java.awt.event.WindowEvent evt) {
for(;;){
setPing();
}
}
But this doesn't even work for the first time.
I didnt put the setPing method because it was too long so here it is:
public String setPing(){
Runtime runtime = Runtime.getRuntime();
try{
Process process = runtime.exec("ping lol.garena.com");
InputStream is = process.getInputStream();
InputStreamReader isr = new InputStreamReader(is);
BufferedReader br = new BufferedReader(isr);
String line;
while ((line = br.readLine()) != null) {
int i = 0;
i = line.indexOf("Average");
if(i > 0){
String finalPing = "";
line.toCharArray();
try
{
finalPing = "";
for(int x = i; x < i + 17; x++)
{
finalPing = finalPing + (line.charAt(x));
}
}catch(IndexOutOfBoundsException e)
{
try
{
finalPing = "";
for(int x = i; x < i + 16; x++)
{
finalPing = finalPing + (line.charAt(x));
}
}catch(IndexOutOfBoundsException f)
{
try
{
finalPing = "";
for(int x = i; x < i + 15; x++)
{
finalPing = finalPing + (line.charAt(x));
}
}catch(IndexOutOfBoundsException g){}
}
}
String final1Ping = finalPing.replaceAll("[^0-9]", "");
return final1Ping;
}
}
}catch(IOException e){
}
return "";
}
UPDATE
Just in case this is important, Im using netbeans. I created a form and put this code in the formWindowOpened evt instead of calling it in main:
private void formWindowOpened(java.awt.event.WindowEvent evt) {
ActionListener timerListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
new PingWorker().execute();
}
};
Timer timer = new Timer(1000, timerListener);
timer.start();
jLabel1.setText(label.getText());
timer.stop();
// TODO add your handling code here:
}
class PingWorker extends SwingWorker {
int time;
#Override
protected Object doInBackground() throws Exception {
time = pingTime("lol.garena.com");
return new Integer(time);
}
#Override
protected void done() {
label.setText("" + time);
}
};
public JComponent getUI() {
return label;
}
public static int pingTime(String hostnameOrIP) {
Socket socket = null;
long start = System.currentTimeMillis();
try {
socket = new Socket(hostnameOrIP, 80);
} catch (IOException ex) {
ex.printStackTrace();
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
}
}
}
long end = System.currentTimeMillis();
return (int) (end - start);
}

Use a Swing Timer for repeating tasks & a SwingWorker for long running tasks. E.G. of both below - it uses a Timer to repeatedly perform a 'long running' task (a ping) in a SwingWorker.
See Concurrency in Swing for more details on the Event Dispatch Thread and doing long running or repeating tasks in a GUI.
This code combines a long running task ('pinging' a server) using SwingWorker invoked from a repeating task (updating the JLabel repeatedly with the times) using a Swing based Timer.
import java.awt.event.*;
import javax.swing.*;
import java.net.Socket;
public class LabelUpdateUsingTimer {
static String hostnameOrIP = "stackoverflow.com";
int delay = 5000;
JLabel label = new JLabel("0000");
LabelUpdateUsingTimer() {
label.setFont(label.getFont().deriveFont(120f));
ActionListener timerListener = new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
new PingWorker().execute();
}
};
Timer timer = new Timer(delay, timerListener);
timer.start();
JOptionPane.showMessageDialog(
null, label, hostnameOrIP, JOptionPane.INFORMATION_MESSAGE);
timer.stop();
}
class PingWorker extends SwingWorker {
int time;
#Override
protected Object doInBackground() throws Exception {
time = pingTime();
return new Integer(time);
}
#Override
protected void done() {
label.setText("" + time);
}
};
public static int pingTime() {
Socket socket = null;
long start = System.currentTimeMillis();
try {
socket = new Socket(hostnameOrIP, 80);
} catch (Exception weTried) {
} finally {
if (socket != null) {
try {
socket.close();
} catch (Exception weTried) {}
}
}
long end = System.currentTimeMillis();
return (int) (end - start);
}
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
new LabelUpdateUsingTimer();
}
};
SwingUtilities.invokeLater(r);
}
}

You could use a Thread. The problem is you are blocking the main thread, thereby blocking your program. To get around this, start a background Thread to update components repeatedly.
(Note: you need to update GUI components on the EDT, so use SwingUtilities.invokeLater)
(new Thread((new Runnable(){
#Override
public void run(){
while(true){
SwingUtilities.invokeLater(new Runnable(){
#Override
public void run(){
refToJLabel.setText(Math.random());
}
});
}
}
}))).start();

JPanel elements are not appearing

I'm using the Swing library to ask a user for their zipcode, but all that is appearing is a box, without the text box, or any of the other elements that I've added in (see code). Also, you likely need to know that I'm trying to get the int AskZip() in my public static void main(String[] args) method.
private static int zip;
public static int AskZip() {
JFrame zaWindow = new JFrame("What Zipcode");
zaWindow.setSize(200, 300);
JPanel jp = new JPanel();
final JTextField tf = new JTextField("Enter Zip Here");
JLabel label = new JLabel();
JButton button = new JButton("Get Weather");
button.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
String sZip = tf.getText();
int rZip = 0;
try {
if (sZip.length() != 5) {
JOptionPane.showMessageDialog(null, "Invalid zipcode!", "Error", JOptionPane.ERROR_MESSAGE);
} else {
rZip = Integer.parseInt(sZip);
}
} catch (NumberFormatException arg) {
JOptionPane.showMessageDialog(null, "Invalid zipcode!", "Error", JOptionPane.ERROR_MESSAGE);
}
zip = rZip;
}
});
label.setText("What is your zipcode?");
jp.add(label);
jp.add(tf);
jp.add(button);
zaWindow.add(jp);
return zip;
}

JFrame zaWindow..
This should be a modal dialog or a JOptionPane. E.G. This country has 3 states, each with 10 postcodes.
import java.awt.*;
import java.util.ArrayList;
import javax.swing.*;
import javax.swing.event.ChangeListener;
class ZipQuery {
public static void main(String[] args) {
Runnable r = new Runnable() {
#Override
public void run() {
ZipNumberModel znm = new ZipNumberModel();
JSpinner zip = new JSpinner(znm);
JOptionPane.showMessageDialog(null, zip, "Enter Zipcode", JOptionPane.QUESTION_MESSAGE);
System.out.println("User chose " + znm.getValue());
}
};
// Swing GUIs should be created and updated on the EDT
// http://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html
SwingUtilities.invokeLater(r);
}
}
class ZipNumberModel extends SpinnerNumberModel {
private ArrayList<Integer> zipCodes;
private int index = 0;
ZipNumberModel() {
zipCodes = new ArrayList<Integer>();
int zip = 10000;
for (int jj = 1; jj < 4; jj++) {
for (int ii = jj * zip; ii < jj * zip + 10; ii++) {
zipCodes.add(new Integer(ii));
}
}
}
#Override
public Object getValue() {
return zipCodes.get(index);
}
#Override
public Object getNextValue() {
if (index < zipCodes.size()-1) {
index++;
} else {
index = 0;
}
return zipCodes.get(index);
}
#Override
public Object getPreviousValue() {
if (index > 0) {
index--;
} else {
index = zipCodes.size()-1;
}
return zipCodes.get(index);
}
}

how can i solve this error

This is the complete code :
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.lang.Thread;
class jProgressBar {
JProgressBar pb;
JButton start;
int i;
jProgressBar() {
buildGUI();
hookUpEvents();
}
public void buildGUI() {
JFrame fr=new JFrame("Progress Bar");
JPanel p=new JPanel();
p.setLayout(new FlowLayout(FlowLayout.CENTER));
JPanel barPanel=new JPanel();
barPanel.setLayout(new GridLayout(2,0,50,50));
pb=new JProgressBar(0,10);
start=new JButton("Start Demo");
fr.add(p);
barPanel.add(start);
barPanel.add(pb);
p.add(barPanel);
fr.setSize(500,500);
fr.setVisible(true);
}
public void hookUpEvents() {
start.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
try {
Runnable r=new Runnable() {
public void run() {
action(ae); // LINE 39
}
};
Thread th=new Thread(r);
th.start();
} catch(Exception exc) {
System.out.println(exc);
}
}
});
}
public void action(ActionEvent ae) {
start.setVisible(false);
try {
Runnable rp=new Runnable() {
public void run() {
i++;
pb.setValue(i);
try {
Thread.sleep(2000);
} catch(Exception exc) {
System.out.println(exc);
}
if(i==5) {
pb.setString("Half Done!");
}
else if(i==10) {
pb.setString("Completed!");
}
}
};
Thread th=new Thread(rp);
th.start();
} catch(Exception exc) {
System.out.println(exc);
}
}
public static void main(String args[]) {
new jProgressBar();
}
}
This is the error produced on cmd:
d:\UnderTest>javac jProgressBar.java
jProgressBar.java:39: local variable ae is accessed from within inner class; needs to be declared fina
l
action(ae);
^
1 error
What is this error and how can I solve this error?

Declare the variable ae as final:
public void actionPerformed(final ActionEvent ae) {
This means that it cannot be assigned a new value, which should be fine according to your current code.

a very nice example for SwingWorker
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.ArrayList;
public class SwingWorkerExample extends JFrame implements ActionListener {
private static final long serialVersionUID = 1L;
private final JButton startButton, stopButton;
private JScrollPane scrollPane = new JScrollPane();
private JList listBox = null;
private DefaultListModel listModel = new DefaultListModel();
private final JProgressBar progressBar;
private mySwingWorker swingWorker;
public SwingWorkerExample() {
super("SwingWorkerExample");
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
getContentPane().setLayout(new GridLayout(2, 2));
startButton = makeButton("Start");
stopButton = makeButton("Stop");
stopButton.setEnabled(false);
progressBar = makeProgressBar(0, 99);
listBox = new JList(listModel);
scrollPane.setViewportView(listBox);
getContentPane().add(scrollPane);
//Display the window.
pack();
setVisible(true);
}
//Class SwingWorker<T,V> T - the result type returned by this SwingWorker's doInBackground
//and get methods V - the type used for carrying out intermediate results by this SwingWorker's
//publish and process methods
private class mySwingWorker extends javax.swing.SwingWorker<ArrayList<Integer>, Integer> {
//The first template argument, in this case, ArrayList<Integer>, is what s returned by doInBackground(),
//and by get(). The second template argument, in this case, Integer, is what is published with the
//publish method. It is also the data type which is stored by the java.util.List that is the parameter
//for the process method, which recieves the information published by the publish method.
#Override
protected ArrayList<Integer> doInBackground() {
//Returns items of the type given as the first template argument to the SwingWorker class.
if (javax.swing.SwingUtilities.isEventDispatchThread()) {
System.out.println("javax.swing.SwingUtilities.isEventDispatchThread() returned true.");
}
Integer tmpValue = new Integer(1);
ArrayList<Integer> list = new ArrayList<Integer>();
for (int i = 0; i < 100; i++) {
for (int j = 0; j < 100; j++) { //find every 100th prime, just to make it slower
tmpValue = FindNextPrime(tmpValue.intValue());
//isCancelled() returns true if the cancel() method is invoked on this class. That is the proper way
//to stop this thread. See the actionPerformed method.
if (isCancelled()) {
System.out.println("SwingWorker - isCancelled");
return list;
}
}
//Successive calls to publish are coalesced into a java.util.List, which is what is received by process,
//which in this case, isused to update the JProgressBar. Thus, the values passed to publish range from
//1 to 100.
publish(new Integer(i));
list.add(tmpValue);
}
return list;
}//Note, always use java.util.List here, or it will use the wrong list.
#Override
protected void process(java.util.List<Integer> progressList) {
//This method is processing a java.util.List of items given as successive arguments to the publish method.
//Note that these calls are coalesced into a java.util.List. This list holds items of the type given as the
//second template parameter type to SwingWorker. Note that the get method below has nothing to do with the
//SwingWorker get method; it is the List's get method. This would be a good place to update a progress bar.
if (!javax.swing.SwingUtilities.isEventDispatchThread()) {
System.out.println("javax.swing.SwingUtilities.isEventDispatchThread() + returned false.");
}
Integer percentComplete = progressList.get(progressList.size() - 1);
progressBar.setValue(percentComplete.intValue());
}
#Override
protected void done() {
System.out.println("doInBackground is complete");
if (!javax.swing.SwingUtilities.isEventDispatchThread()) {
System.out.println("javax.swing.SwingUtilities.isEventDispatchThread() + returned false.");
}
try {
//Here, the SwingWorker's get method returns an item of the same type as specified as the first type parameter
//given to the SwingWorker class.
ArrayList<Integer> results = get();
for (Integer i : results) {
listModel.addElement(i.toString());
}
} catch (Exception e) {
System.out.println("Caught an exception: " + e);
}
startButton();
}
boolean IsPrime(int num) { //Checks whether a number is prime
int i;
for (i = 2; i <= num / 2; i++) {
if (num % i == 0) {
return false;
}
}
return true;
}
protected Integer FindNextPrime(int num) { //Returns next prime number from passed arg.
do {
if (num % 2 == 0) {
num++;
} else {
num += 2;
}
} while (!IsPrime(num));
return new Integer(num);
}
}
private JButton makeButton(String caption) {
JButton b = new JButton(caption);
b.setActionCommand(caption);
b.addActionListener(this);
getContentPane().add(b);
return b;
}
private JProgressBar makeProgressBar(int min, int max) {
JProgressBar progressBar1 = new JProgressBar();
progressBar1.setMinimum(min);
progressBar1.setMaximum(max);
progressBar1.setStringPainted(true);
progressBar1.setBorderPainted(true);
getContentPane().add(progressBar1);
return progressBar1;
}
private void startButton() {
startButton.setEnabled(true);
stopButton.setEnabled(false);
System.out.println("SwingWorker - Done");
}
#Override
public void actionPerformed(ActionEvent e) {
if ("Start" == null ? e.getActionCommand() == null : "Start".equals(e.getActionCommand())) {
startButton.setEnabled(false);
stopButton.setEnabled(true);
// Note that it creates a new instance of the SwingWorker-derived class. Never reuse an old one.
(swingWorker = new mySwingWorker()).execute(); // new instance
} else if ("Stop" == null ? e.getActionCommand() == null : "Stop".equals(e.getActionCommand())) {
startButton.setEnabled(true);
stopButton.setEnabled(false);
swingWorker.cancel(true); // causes isCancelled to return true in doInBackground
swingWorker = null;
}
}
public static void main(String[] args) {
// Notice that it kicks it off on the event-dispatching thread, not the main thread.
SwingUtilities.invokeLater(new Runnable() {
#Override
public void run() {
SwingWorkerExample swingWorkerExample = new SwingWorkerExample();
}
});
}
}

There are some counterproductive issues present.
Swing is single-thread based, and all actions must be done on the EDT. For that reason, your JProgressBar doesn't update correctly. See also Concurrency in Swing.
Don't use Thread.sleep(int) in Swing, and certainly not in an action listener.
By using Runnable, it is possible to update JProgressBar; but as mentioned, the method must be run from invokeLater().
For that, SwingWorker would be better, as shown below and here.
import java.awt.Dimension;
import java.awt.Toolkit;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
public class TestProgressBar {
private static void createAndShowUI() {
JFrame frame = new JFrame("TestProgressBar");
frame.getContentPane().add(new TestPBGui().getMainPanel());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
java.awt.EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
createAndShowUI();
}
});
}
private TestProgressBar() {
}
}
class TestPBGui {
private JPanel mainPanel = new JPanel();
public TestPBGui() {
JButton yourAttempt = new JButton("Your attempt to show Progress Bar");
JButton myAttempt = new JButton("My attempt to show Progress Bar");
yourAttempt.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
yourAttemptActionPerformed();
}
});
myAttempt.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
myAttemptActionPerformed();
}
});
mainPanel.add(yourAttempt);
mainPanel.add(myAttempt);
}
private void yourAttemptActionPerformed() {
Window thisWin = SwingUtilities.getWindowAncestor(mainPanel);
JDialog progressDialog = new JDialog(thisWin, "Uploading...");
JPanel contentPane = new JPanel();
contentPane.setPreferredSize(new Dimension(300, 100));
JProgressBar bar = new JProgressBar(0, 100);
bar.setIndeterminate(true);
contentPane.add(bar);
progressDialog.setContentPane(contentPane);
progressDialog.pack();
progressDialog.setLocationRelativeTo(null);
Task task = new Task("Your attempt");
task.execute();
progressDialog.setVisible(true);
while (!task.isDone()) {
}
progressDialog.dispose();
}
private void myAttemptActionPerformed() {
Window thisWin = SwingUtilities.getWindowAncestor(mainPanel);
final JDialog progressDialog = new JDialog(thisWin, "Uploading...");
JPanel contentPane = new JPanel();
contentPane.setPreferredSize(new Dimension(300, 100));
final JProgressBar bar = new JProgressBar(0, 100);
bar.setIndeterminate(true);
contentPane.add(bar);
progressDialog.setContentPane(contentPane);
progressDialog.pack();
progressDialog.setLocationRelativeTo(null);
final Task task = new Task("My attempt");
task.addPropertyChangeListener(new PropertyChangeListener() {
#Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getPropertyName().equalsIgnoreCase("progress")) {
int progress = task.getProgress();
if (progress == 0) {
bar.setIndeterminate(true);
} else {
bar.setIndeterminate(false);
bar.setValue(progress);
progressDialog.dispose();
}
}
}
});
task.execute();
progressDialog.setVisible(true);
}
public JPanel getMainPanel() {
return mainPanel;
}
}
class Task extends SwingWorker<Void, Void> {
private static final long SLEEP_TIME = 4000;
private String text;
public Task(String text) {
this.text = text;
}
#Override
public Void doInBackground() {
setProgress(0);
try {
Thread.sleep(SLEEP_TIME);// imitate a long-running task
} catch (InterruptedException e) {
}
setProgress(100);
return null;
}
#Override
public void done() {
System.out.println(text + " is done");
Toolkit.getDefaultToolkit().beep();
}
}