Thread: Storing color names and their hexadecimals in hasmap

I was able to make something similar work, though I had the HashMap be a class variable rather than a final variable like you had it.

   import java.util.HashMap;
   import java.awt.event.ActionEvent;
   import java.awt.event.ActionListener;
   import javax.swing.JLabel;
   import javax.swing.JFrame;
   import javax.swing.JPanel;
   import javax.swing.JButton;
   import java.awt.GridLayout;
   import java.awt.Color;
 
   public class TestingThis extends JFrame
   {
 
      private HashMap<String,String> map;
      private JButton red, green, blue;
      private JLabel display;
      private JPanel contentPane;
 
      public TestingThis()
      {
         super("This is a test.");
         contentPane = new JPanel();
         setContentPane(contentPane);
         getContentPane().setLayout(new GridLayout(4,1));
         display = new JLabel();
         getContentPane().add(display);
         red = new JButton("Red");
         getContentPane().add(red);
         map = new HashMap<String,String>();
 
         map.put("Red", "FF0000");
         map.put("Green", "00FF00");
         map.put("Blue", "0000FF");
         red.addActionListener(
               new ActionListener() {
 
                  public void actionPerformed(ActionEvent e)
                  {
 
                     getContentPane().setBackground(Color.RED);
                     display.setText("The hexidecimal for red is " + map.get("Red"));
 
 
                  }});
 
         green = new JButton("Green");
         getContentPane().add(green);
         green.addActionListener(
               new ActionListener() {
 
                  public void actionPerformed(ActionEvent e)
                  {
 
                     getContentPane().setBackground(Color.GREEN);
                     display.setText("The hexidecimal for green is " + map.get("Green"));
 
 
                  }});
 
         blue = new JButton("Blue");
         getContentPane().add(blue);
 
         blue.addActionListener(
               new ActionListener() {
 
                  public void actionPerformed(ActionEvent e)
                  {
 
                     getContentPane().setBackground(Color.BLUE);
                     display.setText("The hexidecimal for blue is " + map.get("Blue"));
 
 
                  }});
 
 
         setVisible(true);
         setDefaultCloseOperation(EXIT_ON_CLOSE);
 
      }
 
      public static void main(String[] args)
      {
         new TestingThis();
      }
 
 
   }

import javax.swing.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.color.*;
import javax.swing.border.*;
 
public class Test extends JFrame{
 
    private JRadioButton red, blue;
    private JLabel display;
    private HashMap<String, String> map = new HashMap<>();
 
    public static void main(String[] args){
 
        Test frame = new Test();
        frame.setTitle("Colors");
        frame.setSize(700, 300);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
 
 
    }
 
    public Test(){
 
        JPanel p1 = new JPanel();
        p1.setLayout(new GridLayout(1,5));
        p1.add(red = new JRadioButton("Red"));
        p1.add(blue = new JRadioButton("Blue"));
 
        add(p1, BorderLayout.NORTH);
        p1.setBorder(new TitledBorder("Group 1"));
 
 
 
        ButtonGroup group = new ButtonGroup();
        group.add(red);
        group.add(blue);
 
 
 
       map.put("Red", "FF0000");
       map.put("Blue", "0000FF");
 
        red.addActionListener(new ActionListener(){
 
            @Override
            public void actionPerformed(ActionEvent e) {
 
 
                getContentPane().setBackground(Color.red);
                display.setText("The hexadecimal for red is #" + map.get("Red"));
 
            }
    });
}

It is showing no errors but it is not running correctly. background still changes color but the text does not appear.

Try initializing the variable "display".

Then add it to your GUI.

Also, try setting p1 to be your content pane or something.

 
 
   import javax.swing.*;
   import java.util.*;
   import java.awt.*;
   import java.awt.event.*;
   import java.awt.color.*;
   import javax.swing.border.*;
 
   public class Test2 extends JFrame{
 
      private JRadioButton red, blue;
      private JLabel display;
      private HashMap<String, String> map = new HashMap<String,String>();
 
      public static void main(String[] args){
 
         Test2 frame = new Test2();
         frame.setTitle("Colors");
         frame.setSize(700, 300);
         frame.setLocationRelativeTo(null);
         frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         frame.setVisible(true);
 
 
      }
 
      public Test2(){
 
         JPanel p1 = new JPanel();
         p1.setLayout(new GridLayout(1,5));
         p1.add(red = new JRadioButton("Red"));
         p1.add(blue = new JRadioButton("Blue"));
 
 
         p1.setBorder(new TitledBorder("Group 1"));
 
 
 
         ButtonGroup group = new ButtonGroup();
         group.add(red);
         group.add(blue);
 
         display = new JLabel();
 
         setContentPane(p1);
         p1.add(display);
 
 
 
         map.put("Red", "FF0000");
         map.put("Blue", "0000FF");
 
         red.addActionListener(
               new ActionListener(){
 
                  @Override
                  public void actionPerformed(ActionEvent e) {
 
                     getContentPane().setBackground(Color.red);
                     display.setText("The hexadecimal for red is #" + map.get("Red"));
 
                  }
               });
      }
   }