Question

I am working on a project that requires me to read colors and Hex codes for the colors into a map from a text file. I have a TreeMap created and it stores and prints properly on the screen, but I can not figure out how to get it to send the data to a combo box. Here is my code thus far…

public class Project extends JFrame{

    JComboBox CBColor = new JComboBox(new String[]
    {"", "AQUA", "BLACK", "BLUE", "BROWN", "FUCHSIA", "GRAY",
    "GREEN", "INDIGO", "LIME", "MAROON", "NAVY", "ORANGE",
    "PINK", "PURPLE", "RED", "SIENNA", "TAN", "TEAL", "WHITE", "YELLOW"});
    JTextArea TAText = new JTextArea(5, 25);
    JButton BApply = new JButton("Apply");
    JButton BExit = new JButton("Exit");

    public Project() {
        JPanel SelectionPanel = new JPanel(new BorderLayout());
        SelectionPanel.add(CBColor, BorderLayout.NORTH);
        SelectionPanel.add(TAText, BorderLayout.CENTER);
        JPanel ApplyPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 10, 10));
        ApplyPanel.add(BApply);
        ApplyPanel.add(BExit);
        add(SelectionPanel, BorderLayout.NORTH);
        add(ApplyPanel, BorderLayout.SOUTH);
        BApply.addActionListener(new ButtonListener());
        BExit.addActionListener(new ExitButtonListener());
    }

    private class ButtonListener implements ActionListener {
            public void actionPerformed(ActionEvent e) {
                String BGColor = "";
                if (CBColor.getSelectedItem() == "AQUA")
                    BGColor = "#00FFFF";
                else if (CBColor.getSelectedItem() == "BLACK")
                    BGColor = "#000000";
                else if (CBColor.getSelectedItem() == "BLUE")
                    BGColor = "#0000FF";
                else if (CBColor.getSelectedItem() == "BROWN")
                    BGColor = "#A52A2A";
                else if (CBColor.getSelectedItem() == "FUCHSIA")
                    BGColor = "#FF00FF";
                else if (CBColor.getSelectedItem() == "GRAY")
                    BGColor = "#BEBEBE";
                else if (CBColor.getSelectedItem() == "GREEN")
                    BGColor = "#008000";
                else if (CBColor.getSelectedItem() == "INDIGO")
                    BGColor = "#4B0082";
                else if (CBColor.getSelectedItem() == "LIME")
                    BGColor = "#00FF00";
                else if (CBColor.getSelectedItem() == "MAROON")
                    BGColor = "#800000";
                else if (CBColor.getSelectedItem() == "NAVY")
                    BGColor = "#000080";
                else if (CBColor.getSelectedItem() == "ORANGE")
                    BGColor = "#FFA500";
                else if (CBColor.getSelectedItem() == "PINK")
                    BGColor = "#FFC0CB";
                else if (CBColor.getSelectedItem() == "PURPLE")
                    BGColor = "#800080";
                else if (CBColor.getSelectedItem() == "RED")
                    BGColor = "#FF0000";
                else if (CBColor.getSelectedItem() == "SIENNA")
                    BGColor = "#A0522D";
                else if (CBColor.getSelectedItem() == "TAN")
                    BGColor = "#D2B48C";
                else if (CBColor.getSelectedItem() == "TEAL")
                    BGColor = "#008080";
                else if (CBColor.getSelectedItem() == "WHITE")
                    BGColor = "#FFFFFF";
                else if (CBColor.getSelectedItem() == "YELLOW")
                    BGColor = "#FFFF00";
                TAText.setBackground(Color.decode(BGColor));
            }
    }

    private class ExitButtonListener implements ActionListener {
            public void actionPerformed(ActionEvent e) {
            System.exit(0);
            }
    }

    public static void main(String[] args) throws Exception {

        Map<String, String> ColorsHex = new TreeMap<String, String>();

        BufferedReader input = new BufferedReader(new FileReader("colors.txt"));
        String line = "";
        while ((line = input.readLine()) != null) {
            String parts[] = line.split(", ");
            ColorsHex.put(parts[0], parts[1]);
        }
        input.close();        
        System.out.println(ColorsHex);
        System.out.print(ColorsHex.keySet());
        System.out.print(ColorsHex.get("RED"));


        Project frame = new Project();
        frame.setTitle("Colors");
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.pack();
        frame.setVisible(true);



    }


}

This compiles and runs, but i am trying to get the combo box to read the values imported instead of entering them, and the listener to read the elements instead of entering them.

Answer 1

JComboBox does not have a constructor that takes a Set. You will have to use one of the available constructors.

Update:

One solution is to use the default constructor JComboBox() initially, call the load to load the colors from your file, and then set the model for the JComboBox:

protected void loadColors() throws IOException {
   Map<String, String> colorsHexMap = new TreeMap<String, String>();
   BufferedReader input = new BufferedReader(new FileReader("colors.txt"));
   ...

   Set<String> keySet = colorsHexMap.keySet();
   String[] keyArray = keySet.toArray(new String[keySet.size()]);
   ComboBoxModel<String> model = new DefaultComboBoxModel<>(keyArray);
   CBColor.setModel(model);
}

Also, if you make your TreeMap a class member variable, you will be able to simplify your hex color selection down to 2 lines:

String bgColor = colorsHexMap.get(CBColor.getSelectedItem());
TAText.setBackground(Color.decode(bgColor));