Question

I’m currently working on an assignment for a first year programming class and, to be honest, programming is not my greatest skill. So any help with this small problem would be much appreciated.I apologise for clogging up the site because of my newbiness.

The program is essentially a number guessing game using temperature, that stores and sorts the guesses (int guessTemperature) from the JTextField into an arraylist and displays via a JOptionMessage, once you have guessed correctly, the lowest guess, the index array of the correct guess, the average of all guesses and the converted temperature in Fahrenheit. It is between 9 and 40 because the assignment specified 40 and the highest number on my student ID. I haven’t included the methods for the avg or index, as the non-functioning arraylist makes it redundant.

The trouble I am having is storing the temperature guesses, whether correct or incorrect, in the arraylist. I test the program manually, literally starting at 9 and working my way up to 40. So if my arraylist was functioning correctly, the output after sorting for lowest guessed temperature should always be 9 because that’s always where I start, but the output for lowest temperature currently is the randomly calculated number and correct guess. Unless my sorting method and find minimum method is incorrect, the arraylist is not being filled with the any guesses apart from the last. So if anyone can suggest to me what is wrong (or if everything is wrong) with my arraylist that it is not capturing each instance of a guess it would be greatly appreciated.

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;
import javax.swing.*;

public class TemperatureFrame extends JFrame {

public JFrame mainFrame;
public JLabel prompt1, prompt2;
public JTextField userInput;
public JLabel comment;
public JButton restart;
public int randomTemperature;
public int min = 9;
public int max = 40;
public int guessTemperature;
public int sumTemperature;
public double avgTemperature;
public int lowestTemperature;
public int convertedTemperature;
public int indexTemperature;
public Color background;
public ArrayList<Integer> arList;

public TemperatureFrame() {

    super("Temperature Guess/Conversion Application");
    prompt1 = new JLabel("Randomly generated temperature is between 9 and 40." );
    prompt2 = new JLabel("Write temperature (your guess) or -1 (for exit) and press enter key:");
    userInput = new JTextField(5);
    userInput.addActionListener(new GuessHandler());       
    comment = new JLabel("The results will be shown here.");
    restart = new JButton("Start Again - Generate A New Temperature");
    restart.addActionListener(
            new ActionListener() {
                @Override
                public void actionPerformed(ActionEvent e) {
                    userInput.setText("");
                    comment.setText("The results will be shown here.");
                    RandomTemperature();
                    userInput.setEditable(true);
                }
            });
    setLayout(new FlowLayout());
    background = Color.LIGHT_GRAY;
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(500, 150);
    setLocationRelativeTo(null);
    setVisible(true);
    setResizable(false);        

    add(prompt1);
    add(prompt2);
    add(userInput);
    add(comment);
    add(restart);

    RandomTemperature();
    ConvertTemperature();   
}

public void RandomTemperature() {
    Random random = new Random();
    randomTemperature = random.nextInt(max - min) + min;
}    

public void ConvertTemperature() {
    convertedTemperature = randomTemperature * 9 / 5 + 32;        
}

class GuessHandler implements ActionListener {

    @Override
    public void actionPerformed(ActionEvent e) {
        {
            arList = new ArrayList<>();
            String str;
            str = userInput.getText().toString();
            guessTemperature = Integer.parseInt(str);
            arList.add(guessTemperature);
            {   
                if (guessTemperature > randomTemperature) {
                    comment.setText("Temperature guessed is higher than the random temperature.");
                    userInput.setText("");
                    userInput.setEditable(true);             
                }
                if (guessTemperature < randomTemperature) {
                    comment.setText("Temperature guessed is lower than the random temperature.");
                    userInput.setText("");
                    userInput.setEditable(true);
                }
                if (guessTemperature == randomTemperature) {
                    Collections.sort(arList);
                    lowestTemperature = Collections.min(arList);
                    comment.setText("Temperature guessed is equal to the random temperature.");
                    JOptionPane.showMessageDialog(null, "Temperature guessed is equal to the random temperature.\n\n1. Lowest temperature is:" + lowestTemperature + "\n2. Average temperature is:" + avgTemperature + "\n3. Array index of correctly guessed temperture is:" + indexTemperature + "\n4. Temperature in Farenheit is:" + convertedTemperature + "\n\nThank you for playing!");                         
                } 
                else if (guessTemperature == -1) {
                    System.exit(0);
                }
            }
        }
    }
}      

}

Answer 1

You might want to move arList = new ArrayList<>(); as an instance variable of the handler class. Now, since the arraylist is initialized inside the actionPerformed method, it gets reinitialized every time the user clicks the button.

(Just gave a grazing look at the program. I could be wrong)