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How do make a login function using BufferedReader?

I am a first-year programming student and I was tasked to make a Login and Register program using Java Swing (Application Window) and BufferedReader+Writer. I am now able to write a username and password into a text file via BWriter, however I have no idea how to make the Login read the text file and only Login when the inputted username and password in their respected TextField matches the one I wrote into the text file. (For reference the text file looks like this after I wrote the supposed username and password from the Register portion: Redman, 1234)
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.SwingConstants;
import java.awt.Font;
import javax.swing.JTextField;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.Reader;
import java.awt.event.ActionEvent;
public class Register {
private JFrame frame;
private JTextField tfNewUser;
private JTextField tfNewPass;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Register window = new Register();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public Register() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setTitle("Register");
frame.setBounds(100, 100, 286, 324);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
JLabel lblNewLabel = new JLabel("REGISTER ");
lblNewLabel.setBounds(10, 11, 250, 26);
lblNewLabel.setFont(new Font("Tahoma", Font.BOLD, 12));
lblNewLabel.setHorizontalAlignment(SwingConstants.CENTER);
frame.getContentPane().add(lblNewLabel);
tfNewUser = new JTextField();
tfNewUser.setBounds(117, 48, 143, 20);
frame.getContentPane().add(tfNewUser);
tfNewUser.setColumns(10);
tfNewPass = new JTextField();
tfNewPass.setBounds(117, 79, 143, 20);
tfNewPass.setColumns(10);
frame.getContentPane().add(tfNewPass);
JButton btnReg = new JButton("REGISTER");
btnReg.setBounds(10, 110, 250, 23);
btnReg.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
String regUser = tfNewUser.getText().toString();
String regPass = tfNewPass.getText().toString();
addReg(regUser, regPass);
}
});
frame.getContentPane().add(btnReg);
JButton btnUpdate = new JButton("UPDATE CREDENTIALS");
btnUpdate.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
UpdateCreds newformu = new UpdateCreds();
newformu.main(null);
frame.setVisible(false);
}
});
btnUpdate.setBounds(10, 213, 250, 23);
frame.getContentPane().add(btnUpdate);
JButton btnReturn = new JButton("RETURN TO LOGIN");
btnReturn.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Login newform = new Login();
newform.main(null);
frame.setVisible(false);
}
});
btnReturn.setBounds(10, 142, 250, 23);
frame.getContentPane().add(btnReturn);
JLabel lblNewLabel_1 = new JLabel("New Username: ");
lblNewLabel_1.setBounds(10, 48, 97, 14);
frame.getContentPane().add(lblNewLabel_1);
JLabel lblNewLabel_1_1 = new JLabel("New Password: ");
lblNewLabel_1_1.setBounds(10, 82, 97, 14);
frame.getContentPane().add(lblNewLabel_1_1);
JButton btnDeleteAcc = new JButton("DELETE ACCOUNT");
btnDeleteAcc.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
deleteAcc();
}
});
btnDeleteAcc.setBounds(10, 247, 250, 23);
frame.getContentPane().add(btnDeleteAcc);
JLabel lblAccountSettings = new JLabel("ACCOUNT SETTINGS");
lblAccountSettings.setBounds(10, 176, 250, 26);
lblAccountSettings.setHorizontalAlignment(SwingConstants.CENTER);
lblAccountSettings.setFont(new Font("Tahoma", Font.BOLD, 12));
frame.getContentPane().add(lblAccountSettings);
}
public void errorPane (String msg, String status) {
JOptionPane.showMessageDialog(frame, msg, status, JOptionPane.ERROR_MESSAGE);
}
public void succMess (String smsg, String status2) {
JOptionPane.showMessageDialog(frame, smsg, status2, JOptionPane.INFORMATION_MESSAGE);
}
public void clearTF() {
tfNewUser.setText("");
tfNewPass.setText("");
}
public void addReg(String regUser, String regPass) {
try {
BufferedWriter bw = new BufferedWriter(new FileWriter("Creds", true));
bw.write(regUser+", "+regPass);
bw.flush();
bw.newLine();
bw.close();
succMess ("Account registered!", "SUCCESS");
clearTF();
}
catch (Exception e) {
errorPane("There is a problem with the data. Please input new data.", "ERROR" );
}
}
public void deleteAcc() {
try {
String record;
String regUser = tfNewUser.getText().toString();
File tempCred = new File("Creds_temp");
File cred = new File ("Creds");
BufferedReader br = new BufferedReader(new FileReader(cred));
BufferedWriter bw = new BufferedWriter(new FileWriter(tempCred));
while((record = br.readLine())!=null) {
if(record.contains(regUser))
continue;
bw.write(record);
bw.flush();
bw.newLine();
}
br.close();
bw.close();
cred.delete();
tempCred.renameTo(cred);
succMess ("Account Deleted!", "SUCCESS");
}
catch (Exception e) {
errorPane("Cannot find account. Please register an account first.", "ERROR" );
}
}
}

So assuming that the login file only deals with the authentication...
Read the .txt file line by line (I'm using Java Scanner for convenience, but you could use FileReader or anything else as well)
Split each line by comma delimiters and store the data in a hash map
Compare whether the user input matches one
In Login.java:
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
import java.util.HashMap;
public class Login {
private HashMap<String, String> userData = new HashMap<String, String>();
private String name;
private String password;
void readFile() {
try {
// read file
File file = new File("passwords.txt"); // replace with file name!!
Scanner reader = new Scanner(file);
// loop through each line inside the file being read
while (reader.hasNextLine()) {
String str = reader.nextLine();
String[] user = str.split(", "); // user[0] = anything before ", " and user[1] = anything after ", "
userData.put(user[0], user[1]); // store username and password
}
reader.close(); // remember to close the reader
} catch (FileNotFoundException e) {
System.out.println("Something happened...");
e.printStackTrace();
}
}
public boolean loggedIn() {
return password.equals(userData.get(name));
}
// constructor to execute on instance creation
public Login(String name, String password) {
// initialize data
this.name = name;
this.password = password;
readFile();
}
}
And pretend your user data file (passwords.txt) looks something like:
Redman, 1234
Bob, $up3r-$ecur3
Rob, pls don't hack
Using the class is pretty easy:
Login attempt = new Login(username, password); // replace with requested variables as string
boolean success = attempt.loggedIn();
if(success) {
// logged in successfully
} else {
// incorrect username or password!
}
Working (only login) example.
Hope that helps you get somewhere.

Display text from one class to the GUI class

I'm new to Java and I have this code that I use to connect to a server using sockets
Client Class Code
public class Client {
Socket mysocket;
BufferedReader inFromServer;
DataOutputStream outToServer;
public Socket connect(String nameServer, int portServer) {
try
{
mysocket=new Socket(nameServer, portServer);
outToServer=new DataOutputStream(mysocket.getOutputStream());
inFromServer=new BufferedReader(new InputStreamReader(mysocket.getInputStream()));
}
catch(UnknownHostException e)
{
System.err.println("Host error"); // Display Error
}
catch(Exception e)
{
System.out.print(e.getMessage());
System.out.print("Connection Error!"); // Display Error
System.exit(1);
}
return mysocket;
}
GUI Code
package Client;
import java.awt.EventQueue;
import javax.swing.text.BadLocationException;
import javax.swing.text.Style;
import javax.swing.text.StyleConstants;
import javax.swing.text.StyledDocument;
import javax.swing.JFrame;
import javax.swing.JPanel;
import java.awt.Color;
import java.awt.SystemColor;
import javax.swing.JTextField;
import javax.swing.JLabel;
import javax.swing.SwingConstants;
import java.awt.Font;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JTextPane;
public class WindowClient {
private JFrame frmSocketConnection;
private JTextField TxtIP;
private JTextField TxtPort;
private JTextField TxtInput;
Client client = new Client();
public static boolean isNumeric(String strNum) {
if (strNum == null) {
return false;
}
try {
double d = Double.parseDouble(strNum);
} catch (NumberFormatException nfe) {
return false;
}
return true;
}
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
WindowClient window = new WindowClient();
window.frmSocketConnection.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
*/
public WindowClient() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frmSocketConnection = new JFrame();
frmSocketConnection.setTitle("Socket Connection");
frmSocketConnection.getContentPane().setBackground(Color.WHITE);
frmSocketConnection.setBounds(100, 100, 983, 633);
frmSocketConnection.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frmSocketConnection.getContentPane().setLayout(null);
JPanel panel = new JPanel();
panel.setBackground(Color.WHITE);
panel.setBounds(725, 0, 244, 596);
frmSocketConnection.getContentPane().add(panel);
panel.setLayout(null);
TxtIP = new JTextField();
TxtIP.setFont(new Font("Tahoma", Font.PLAIN, 16));
TxtIP.setBounds(10, 89, 224, 34);
panel.add(TxtIP);
TxtIP.setColumns(10);
JLabel lblIP = new JLabel("IP Address");
lblIP.setFont(new Font("Tahoma", Font.BOLD, 18));
lblIP.setHorizontalAlignment(SwingConstants.CENTER);
lblIP.setBounds(10, 45, 224, 34);
panel.add(lblIP);
TxtPort = new JTextField();
TxtPort.setFont(new Font("Tahoma", Font.PLAIN, 16));
TxtPort.setColumns(10);
TxtPort.setBounds(10, 216, 224, 34);
panel.add(TxtPort);
JLabel lblPort = new JLabel("IP Port");
lblPort.setHorizontalAlignment(SwingConstants.CENTER);
lblPort.setFont(new Font("Tahoma", Font.BOLD, 18));
lblPort.setBounds(10, 172, 224, 34);
panel.add(lblPort);
JButton btnConnect = new JButton("Connect");
btnConnect.setFocusPainted(false);
btnConnect.setBackground(SystemColor.controlHighlight);
btnConnect.setFont(new Font("Tahoma", Font.BOLD, 18));
btnConnect.setBounds(34, 317, 176, 48);
panel.add(btnConnect);
JButton btnDisconnect = new JButton("Disconnect");
btnDisconnect.setFocusPainted(false);
btnDisconnect.setEnabled(false);
btnDisconnect.setFont(new Font("Tahoma", Font.BOLD, 18));
btnDisconnect.setBackground(SystemColor.controlHighlight);
btnDisconnect.setBounds(34, 396, 176, 48);
panel.add(btnDisconnect);
TxtInput = new JTextField();
TxtInput.setFont(new Font("Tahoma", Font.PLAIN, 16));
TxtInput.setForeground(Color.WHITE);
TxtInput.setBackground(Color.DARK_GRAY);
TxtInput.setBounds(10, 547, 617, 39);
frmSocketConnection.getContentPane().add(TxtInput);
TxtInput.setColumns(10);
JButton btnEnter = new JButton("Enter");
btnEnter.setFocusPainted(false);
btnEnter.setBackground(SystemColor.controlHighlight);
btnEnter.setFont(new Font("Tahoma", Font.PLAIN, 18));
btnEnter.setBounds(623, 547, 92, 39);
frmSocketConnection.getContentPane().add(btnEnter);
JTextPane TxtConsole = new JTextPane();
StyledDocument doc = TxtConsole.getStyledDocument();
Style style = TxtConsole.addStyle("Stile", null);
TxtConsole.setFont(new Font("Monospaced", Font.PLAIN, 16));
TxtConsole.setForeground(Color.WHITE);
TxtConsole.setBackground(Color.DARK_GRAY);
TxtConsole.setBounds(10, 10, 705, 525);
frmSocketConnection.getContentPane().add(TxtConsole);
btnConnect.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btnConnect.setEnabled(false);
btnDisconnect.setEnabled(true);
if (TxtIP.getText().length() == 0 || TxtPort.getText().length() == 0) {
StyleConstants.setForeground(style, Color.red);
try {
doc.insertString(doc.getLength(), "Error. One field is empty! \n",style);
btnConnect.setEnabled(true);
btnDisconnect.setEnabled(false);
} catch (BadLocationException e1) {
e1.printStackTrace();
}
}
else if (!isNumeric(TxtPort.getText())) {
StyleConstants.setForeground(style, Color.red);
try {
doc.insertString(doc.getLength(), "The port field has to be a number! \n",style);
btnConnect.setEnabled(true);
btnDisconnect.setEnabled(false);
} catch (BadLocationException e1) {
e1.printStackTrace();
}
}
else {
StyleConstants.setForeground(style, Color.white);
try {
doc.insertString(doc.getLength(), "Connection... \n",style);
} catch (BadLocationException e1) {
e1.printStackTrace();
}
}
}
});
TxtInput.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
TxtInput.setText("");
}
});
btnEnter.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
}
});
btnDisconnect.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
TxtIP.setText("");
TxtPort.setText("");
}
});
}
}
and I have a GUI in another class. In that class I have a JTextPane that I want to use as a "console" that display anything
This is an image of the GUI that i have at the moment
I want to display the error strings from the Client class into the JTextPane that it's in another class and I don't really know how to do it

There are many ways to communicate between data and ensure to pass it.
You can choose to throw the error/exception from Client class and ensure to catch it and put that error into the JTextPane
I could simply try this out:
public static class Client {
Socket mysocket;
BufferedReader inFromServer;
DataOutputStream outToServer;
public Socket connect(String nameServer, int portServer) throws Exception {
try
{
mysocket=new Socket(nameServer, portServer);
outToServer=new DataOutputStream(mysocket.getOutputStream());
inFromServer=new BufferedReader(new InputStreamReader(mysocket.getInputStream()));
}
catch(UnknownHostException e)
{
throw new Exception("Unknown Host Error: " + e.getMessage());
}
catch(Exception e)
{
System.out.print("Connection Error!"); // Display Error
throw new Exception("Connection Error! " + e.getMessage());
}
return mysocket;
}
}
A very simple version would be:
Client c = new Client();
String errorMessage = "";
try {
c.connect("localhost", 8010);
} catch (Exception e) {
errorMessage = e.getMessage();
}
JTextPane pane = new JTextPane();
SimpleAttributeSet attributeSet = new SimpleAttributeSet();
StyleConstants.setBold(attributeSet, true);
// Set the attributes before adding text
pane.setCharacterAttributes(attributeSet, true);
// A very simple version of that errorMessage for illustrations only
pane.setText(errorMessage == null ? "Welcome" : errorMessage);
In your case, if you are connecting on a button action, then:
btnConnect.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
btnConnect.setEnabled(false);
btnDisconnect.setEnabled(true);
// if-else
// ...
else {
StyleConstants.setForeground(style, Color.white);
try {
Client c = new Client();
String errorMessage = "";
try {
c.connect("localhost", 8010);
doc.insertString(doc.getLength(), "Connecting...", style);
} catch (Exception e) {
// Setting the error Message
doc.insertString(doc.getLength(), e.getMessage(), style);
}
} catch (BadLocationException e1) {
e1.printStackTrace();
}
}
}
});

Java no UI update after Thread

So, I have got this problem in my Java Swing project where I am making a bot that automatically runs through a whileloop and outputs a text that the user can define in a textfield.
Here you can see my code for adding a textline into a jlabel into my frame:
btnAddTalking = new JButton("Add");
btnAddTalking.setBounds(144, 211, 146, 23);
btnAddTalking.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(!txtTalk.getText().equals("")) {
JLabel newLabel = new JLabel(txtTalk.getText());
newLabel.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent arg0) {
frame.remove(newLabel);
frame.repaint();
}
});
newLabel.setHorizontalAlignment(SwingConstants.CENTER);
newLabel.setBounds(159, yLabel, 101, 20);
frame.getContentPane().add(newLabel);
yLabel = yLabel + 20;
frame.getContentPane().setLayout(null);
frame.repaint();
Talk.addTalk(txtTalk.getText());
}
}
});
frame.getContentPane().add(btnAddTalking);
frame.getContentPane().add(lblNewLabel);
frame.getContentPane().add(lblDelayInMs);
After that I start my bot by pressing the following button:
btnStartTalking = new JButton("Start AutoTalk");
btnStartTalking.setBounds(144, 143, 146, 23);
btnStartTalking.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
int robotDelay = Integer.parseInt(timeTalk.getText());
Talk.action = "start";
robotTalk = txtTalk.getText();
if (rdbtnRed.isSelected() == true) {
robotTalk = "red:" + txtTalk.getText();
} else if (rdbtnFlash.isSelected() == true) {
robotTalk = "flash1:" + txtTalk.getText();
} else if (rdbtnGlow.isSelected() == true) {
robotTalk = "glow1:" + txtTalk.getText();
}
autoTalkStart = new Runnable() {
public void run() {
try {
btnStartTalking.setEnabled(false);
btnStopTalking.setEnabled(true);
btnAddTalking.setEnabled(false);
Talk test = new Talk(robotDelay);
} catch (AWTException | InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
new Thread(autoTalkStart).start();
}
});
Via that button I start a thread which runs through a code that outputs the string. But after I've runned that Thread, my frame doesn't show newly-added jlabels anymore that you've added by clicking the btnAddTalking-button after you've run the Thread by clicking on the btnStartTalking-button! So, my question is: does anyone now how that's even possible (why my UI doesn't update anymore after i've run the thread)?
Greetz,
Jarnov
Here you can see my whole code for the two classes (class 1):
import java.awt.EventQueue;
import java.awt.event.InputEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;
import com.sun.glass.events.KeyEvent;
import com.sun.glass.ui.Robot;
import java.awt.AWTException;
import java.awt.BorderLayout;
import javax.swing.BoxLayout;
import javax.swing.ButtonGroup;
import javax.swing.ButtonModel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import javax.swing.JLabel;
import javax.swing.GroupLayout;
import javax.swing.ImageIcon;
import javax.swing.GroupLayout.Alignment;
import javax.swing.SpringLayout;
import javax.swing.SwingConstants;
import javax.swing.JRadioButton;
public class AutoTalker {
private static JFrame frame;
private JTextField txtTalk;
private JTextField timeTalk;
public String robotTalk;
private JButton btnStopTalking;
private JButton btnAddTalking;
private JButton btnStartTalking;
private int yLabel = 266;
private Runnable autoTalkStart;
/**
* Launch the application.
*/
public static void NewFrame() {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
AutoTalker window = new AutoTalker();
window.frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
/**
* Create the application.
* #return
*/
public AutoTalker() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 415);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setTitle("AutoTalker");
frame.getContentPane().setLayout(null);
JRadioButton rdbtnGlow = new JRadioButton("Glow");
rdbtnGlow.setBounds(6, 113, 64, 23);
rdbtnGlow.setActionCommand("glow");
frame.getContentPane().add(rdbtnGlow);
JRadioButton rdbtnFlash = new JRadioButton("Flash");
rdbtnFlash.setBounds(182, 113, 69, 23);
rdbtnGlow.setActionCommand("flash");
frame.getContentPane().add(rdbtnFlash);
JRadioButton rdbtnRed = new JRadioButton("Red");
rdbtnRed.setBounds(364, 113, 64, 23);
rdbtnGlow.setActionCommand("red");
frame.getContentPane().add(rdbtnRed);
final ButtonGroup rdbtnPressed = new ButtonGroup();
rdbtnPressed.add(rdbtnRed);
rdbtnPressed.add(rdbtnFlash);
rdbtnPressed.add(rdbtnGlow);
txtTalk = new JTextField();
txtTalk.setBounds(130, 28, 173, 20);
txtTalk.setColumns(10);
btnStopTalking = new JButton("Stop AutoTalk");
btnStopTalking.setBounds(144, 177, 146, 23);
btnStopTalking.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
Talk.action = "stop";
btnStartTalking.setEnabled(true);
btnStopTalking.setEnabled(false);
btnAddTalking.setEnabled(true);
frame.repaint();
}
});
btnStartTalking = new JButton("Start AutoTalk");
btnStartTalking.setBounds(144, 143, 146, 23);
btnStartTalking.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
int robotDelay = Integer.parseInt(timeTalk.getText());
Talk.action = "start";
robotTalk = txtTalk.getText();
if (rdbtnRed.isSelected() == true) {
robotTalk = "red:" + txtTalk.getText();
} else if (rdbtnFlash.isSelected() == true) {
robotTalk = "flash1:" + txtTalk.getText();
} else if (rdbtnGlow.isSelected() == true) {
robotTalk = "glow1:" + txtTalk.getText();
}
autoTalkStart = new Runnable() {
public void run() {
try {
btnStartTalking.setEnabled(false);
btnStopTalking.setEnabled(true);
btnAddTalking.setEnabled(false);
Talk test = new Talk(robotDelay);
} catch (AWTException | InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
};
new Thread(autoTalkStart).start();
frame.repaint();
}
});
timeTalk = new JTextField();
timeTalk.setBounds(174, 71, 86, 20);
timeTalk.setColumns(10);
JLabel lblNewLabel = new JLabel("Text:");
lblNewLabel.setBounds(24, 28, 46, 20);
JLabel lblDelayInMs = new JLabel("Delay in ms:");
lblDelayInMs.setBounds(24, 71, 101, 20);
frame.getContentPane().add(txtTalk);
frame.getContentPane().add(btnStartTalking);
frame.getContentPane().add(btnStopTalking);
frame.getContentPane().add(timeTalk);
btnAddTalking = new JButton("Add");
btnAddTalking.setBounds(144, 211, 146, 23);
btnAddTalking.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
if(!txtTalk.getText().equals("")) {
JLabel newLabel = new JLabel(txtTalk.getText());
newLabel.addMouseListener(new MouseAdapter() {
public void mouseClicked(MouseEvent arg0) {
frame.remove(newLabel);
frame.repaint();
}
});
newLabel.setHorizontalAlignment(SwingConstants.CENTER);
newLabel.setBounds(159, yLabel, 101, 20);
frame.getContentPane().add(newLabel);
yLabel = yLabel + 20;
frame.getContentPane().setLayout(null);
frame.repaint();
Talk.addTalk(txtTalk.getText());
}
}
});
frame.getContentPane().add(btnAddTalking);
frame.getContentPane().add(lblNewLabel);
frame.getContentPane().add(lblDelayInMs);
btnStopTalking.setEnabled(false);
}
}
class 2:
import java.awt.AWTException;
import java.awt.Robot;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.io.IOException;
import java.util.ArrayList;
public class Talk extends AutoTalker {
Robot robot = new Robot();
public static String action;
public static ArrayList<String> Talks = new ArrayList<String>();
public Talk(int wait) throws AWTException, InterruptedException {
robot.delay(5000);
while(action == "start") {
for(int i = 0; i < Talks.size();i++) {
String text = Talks.get(i);
type(text);
robot.delay(wait);
}
}
}
public static void addTalk(String text) {
Talks.add(text);
}
private void type(String s)
{
for (int i = 0; i < s.length(); i++){
char c = s.charAt(i);
switch(c) {
case '!':
robot.keyPress(KeyEvent.VK_SHIFT);
robot.keyPress(KeyEvent.VK_1);
robot.keyRelease(KeyEvent.VK_SHIFT);
robot.keyRelease(KeyEvent.VK_1);
break;
case ':':
robot.keyPress(KeyEvent.VK_SHIFT);
robot.keyPress(KeyEvent.VK_SEMICOLON);
robot.keyRelease(KeyEvent.VK_SEMICOLON);
robot.keyRelease(KeyEvent.VK_SHIFT);
break;
default:
robot.keyPress(Character.toUpperCase(c));
break;
}
robot.delay(10);
}
robot.keyPress(KeyEvent.VK_ENTER);
robot.keyRelease(KeyEvent.VK_ENTER);
robot.delay(10);
}
}

Use instead
invalidate();
validate();

I cant get my try catch to work in java

So here is my GUI as you can see.
import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
public class Frame1 {
private JFrame frame;
private JTextField textFieldnum1;
private JTextField textFieldnum2;
private JTextField textFieldAns;
private Termostat thermo;
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
Frame1 window = new Frame1();
window.frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}
public Frame1() {
initialize();
}
private void initialize() {
thermo = new Termostat();
frame = new JFrame();
frame.setBounds(100, 100, 696, 250);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().setLayout(null);
textFieldnum1 = new JTextField();
textFieldnum1.setBounds(176, 11, 147, 46);
frame.getContentPane().add(textFieldnum1);
textFieldnum1.setColumns(10);
textFieldnum2 = new JTextField();
textFieldnum2.setBounds(176, 154, 147, 46);
frame.getContentPane().add(textFieldnum2);
textFieldnum2.setColumns(10);
JButton btnNewButton = new JButton("Convert to celcius");
btnNewButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent arg0) {
double myf = thermo.convertToCelcius(Double.parseDouble(textFieldnum1.getText()));
textFieldAns.setText(String.valueOf(myf));
}
});
btnNewButton.setBounds(0, 0, 171, 68);
frame.getContentPane().add(btnNewButton);
JButton btnNewButton_1 = new JButton("Convert to fahrenheit");
btnNewButton_1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
double myf = thermo.convertToFahrenheit(Double.parseDouble(textFieldnum2.getText()));
textFieldAns.setText(String.valueOf(myf));
}
});
btnNewButton_1.setBounds(0, 143, 171, 68);
frame.getContentPane().add(btnNewButton_1);
textFieldAns = new JTextField();
textFieldAns.setBounds(354, 90, 147, 46);
frame.getContentPane().add(textFieldAns);
textFieldAns.setColumns(10);
JLabel lblNewLabel = new JLabel("Converted");
lblNewLabel.setBounds(285, 94, 112, 38);
frame.getContentPane().add(lblNewLabel);
}
}
And here comes my problem. When i made my class that i wanna run the input in to calculate celcius to fahrenheit, i dont want it to crash when i type anything else than numbers. but i cant get it to work so i need you guys help to get the try catch to work.
Im very thankful for all help i get.
import javax.swing.JOptionPane;
public class Termostat {
public double convertToCelcius(double input) {
double far = 0;
try {
far = (input - 32) * 5 / 9;
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "Wrong input");
return far;
}
return far;
}
public double convertToFahrenheit(double input) {
double cel = 1;
try {
cel = (input * 9 / 5) + 32;
} catch (Exception e) {
JOptionPane.showMessageDialog(null, "Wrong input");
return cel;
}
return cel;
}
}

This is the line where you get probably an Exception:
double myf = thermo.convertToFahrenheit(Double.parseDouble(textFieldnum2.getText()));
So guard it with a NumberFormatException (parseDouble).

You can use the NumberUtil.isNumber(str) to check if the input is a number. Here is more information

you must use try catch when you want to parse text field texts to Double using this method Double.parseDouble(text)
write them them like this and remove your try catches inside your convertToFahrenheit and convertToCelcius methods
JButton btnNewButton_1 = new JButton("Convert to fahrenheit");
btnNewButton_1.addActionListener(new ActionListener() {
#Override
public void actionPerformed(java.awt.event.ActionEvent e) {
try { // start trying to parse input string to double
double myf = thermo.convertToFahrenheit(Double.parseDouble(textFieldnum2.getText()));
textFieldAns.setText(String.valueOf(myf));
} catch (NumberFormatException ex) { // catch the exception that you mentioned
JOptionPane.showMessageDialog(null, "Wrong input");
textFieldAns.setText("");
}
}
});

Trying to read a text file into a JTextArea

I'm trying to open a text file and add its value into a String variable to then set in a JTextArea. No matter what I do it always returns nothing in the textarea.
I want it change the text like it does when you hit the clear button, but I want to change it to what's in the Test.txt file it makes.
package texteditor;
import java.awt.FlowLayout;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.StringSelection;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextArea;
public class GUI extends JFrame {
//GUI Variables
private JButton save;
private JButton clear;
private JButton copy;
private JButton paste;
private JButton open;
private JTextArea textField;
private StringSelection stringSelection;
private Clipboard clipboard;
String textFieldWritable;
public GUI() {
super("Text Editor");
//Sets Layout
setLayout(new FlowLayout());
save = new JButton("Save");
add(save);
clear = new JButton("Clear");
add(clear);
open = new JButton("Open");
add(open);
textField = new JTextArea(10, 35);
add(textField);
handler handle = new handler();
save.addActionListener(handle);
clear.addActionListener(handle);
}
private class handler implements ActionListener {
#Override
public void actionPerformed(ActionEvent event) {
if (event.getSource() == save) {
textFieldWritable = String.format("%s", textField.getText());
try {
FileWriter fileWrite = new FileWriter("Text.txt");
PrintWriter printWrite = new PrintWriter(fileWrite);
printWrite.println(textFieldWritable);
printWrite.close();
} catch (IOException e) {
JOptionPane.showMessageDialog(null,
"Error, File Already Exists!", "Error",
JOptionPane.ERROR_MESSAGE);
}
} else if (event.getSource() == clear) {
textField.setText("");
} else if (event.getSource() == open) {
try {
FileReader fileReader = new FileReader("Text.txt");
BufferedReader bufferedReader = new BufferedReader(fileReader);
String inputFile = "";
String textFieldReadable = bufferedReader.readLine();
while (textFieldReadable != null) {
inputFile += textFieldReadable;
textFieldReadable = bufferedReader.readLine();
}
System.out.println("inputFile");
} catch (FileNotFoundException ex) {
System.out.println("no such file exists");
} catch (IOException ex) {
System.out.println("unkownerror");
}
}
}
}
}

To me, it looks like you never set the text you've read to the text area.
try {
FileReader fileReader = new FileReader("Text.txt");
BufferedReader bufferedReader = new BufferedReader(fileReader);
String inputFile = "";
String textFieldReadable = bufferedReader.readLine();
while (textFieldReadable != null){
inputFile += textFieldReadable;
textFieldReadable = bufferedReader.readLine();
}
System.out.println("inputFile");
// Opps //
textField.setText(inputFile);
}
catch (FileNotFoundException ex) {
System.out.println("no such file exists");
}
catch (IOException ex) {
System.out.println("unkownerror");
}
Personally, I'd just use the functionality provide by JTextComponent and pass it a Reader and allow it to read itself.
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileReader;
import java.io.Reader;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class TextAreaReadTest {
public static void main(String[] args) {
new TextAreaReadTest();
}
public TextAreaReadTest() {
EventQueue.invokeLater(new Runnable() {
#Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JTextArea textArea;
public TestPane() {
setLayout(new BorderLayout());
textArea = new JTextArea(10, 80);
add(new JScrollPane(textArea));
JButton read = new JButton("Read");
read.addActionListener(new ActionListener() {
#Override
public void actionPerformed(ActionEvent e) {
Reader reader = null;
try {
reader = new FileReader(new File("D:/SWANH.txt"));
textArea.read(reader, "The force is strong with this one");
} catch (Exception exp) {
exp.printStackTrace();
} finally {
try {
reader.close();
} catch (Exception exp) {
}
}
}
});
add(read, BorderLayout.SOUTH);
}
}
}

This Code Worked for me
public DisplayText() throws IOException {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
setContentPane(contentPane);
contentPane.setLayout(null);
textArea.setBounds(15, 13, 424, 210);
textArea.setEditable(false);
contentPane.add(textArea);
JScrollPane scrollPane = new JScrollPane(textArea);
scrollPane.setBounds(12, 12, 424, 185);
contentPane.add(scrollPane);
JButton btnPatchDetails = new JButton("Details");
btnPatchDetails.setBounds(135, 234, 137, 25);
contentPane.add(btnPatchDetails);
btnPatchDetails.addActionListener(this);
btnPatchDetails.setActionCommand("Patch Details");
JButton btnNext = new JButton("Next");
btnNext.setBounds(314, 234, 107, 25);
contentPane.add(btnNext);
JLabel lblDependancyPatchAvailable = new JLabel("Dependancy Patch Available : ");
lblDependancyPatchAvailable.setBounds(22, 209, 220, 15);
contentPane.add(lblDependancyPatchAvailable);
lblAvailability.setBounds(254, 209, 61, 15);
contentPane.add(lblAvailability);
}
public void actionPerformed(ActionEvent e) {
if ("Patch Details".equals(e.getActionCommand())) {
BufferedReader reader = null;
JarFile jarFile = null;
try {
String inputFile = "readMe/tempReadme.txt";
String write;
jarFile = new JarFile(inputJar);
JarEntry entry = jarFile.getJarEntry(inputFile);
reader = new BufferedReader(new InputStreamReader(jarFile.getInputStream(entry)));
String line,searchStr = "Patch Details",endStr = "Problem:";
boolean readFlag = false;
boolean writeFlag = false;
while ((line = reader.readLine()) != null) {
if (line.trim().contains(searchStr)) {
readFlag = true;
}
if (line.trim().equals(endStr)) {
break;
}
if (readFlag) {
StringTokenizer tempTokenizer = new StringTokenizer(line,"");
while (tempTokenizer.hasMoreElements()) {
write = tempTokenizer.nextToken();
textArea.append(write + "\n");
}
}
writeFlag = true;
}
if(writeFlag){
lblAvailability.setText("YES");
} else {
lblAvailability.setText("");
}
lblAvailability.getText();
} catch (Exception ex) {
ex.printStackTrace();
} finally {
try {
jarFile.close();
reader.close();
} catch (IOException e1) {
e1.printStackTrace();
}
}
}