如何将文本文件中的ArrayList填充到JCombobox

Question

I am trying to pass an ArrayList to a JComboBox when it is clicked.

Here are the pictures, and I also want to how to get and information after ":" so i make calculation eg 1 USA:1.02 -> get the value after :1.02 when ID 1 is selected then calculate the value from the users input from the text field 1 to populate the result.

This is the code :

private void cbCountryActionPerformed(java.awt.event.ActionEvent evt) {                                          

    try{
        //File reader method
        FileReader file = new FileReader("/Users/MacbookDev/Desktop/countryrates.txt");
        BufferedReader reader = new BufferedReader(file);
        String text = "";
        String line = reader.readLine();
        while (line != null)
        {
            text += line;
            line = reader.readLine();

        }
        cbCountry.addItem(text);

    }catch(Exception e){
        JOptionPane.showMessageDialog(null, e); 
    }

Answer 1

    while (line != null)
    {
        text += line;
        line = reader.readLine();

    }
    cbCountry.addItem(text);

Don't create a string of all the text in the file. You need to add each line of text to the combo box as a separate item:

    while (line != null)
    {
        cbCountry.addItem(line);

        line = reader.readLine();

    }

Also, if you want to store multiple pieces of data in the combo box, then you need to create a custom Object for the data and then create a custom renderer to display the data. See Combo Box With Custom Renderer for more information and examples.