如何在Java的JList中显示数组列表？

Question

I have an arraylist and want to show it on Jlist using gui, I am using drag and drop to make the form, so I need to fill the list dynamically. I tried to get into the properties of the Jlist and make the model is a custom code but the problem which happened that the array list takes its elements from a text file, that means when I want to fill the array list I should call a method one of its parameters is a name of file. When using this method try and catch shohld be used but when I set the model of the Jlist it minds use it! What should I do to make my array list shown on the form as a list?

    public static ArrayList<Beverage> readBeverageTextFile(String fileName) throws FileNotFoundException, IOException {
    ArrayList<Beverage> bevList = new ArrayList<>();
    Reader reader = new FileReader(fileName);
    BufferedReader buf = new BufferedReader(reader);
    String line;
    while (true) {

        line = buf.readLine();
        if (line == null) {
            break;
        }

        try {
            StringTokenizer tokenizer = new StringTokenizer(line, "|");

            String name = tokenizer.nextToken();
            //System.out.println("The name is " + name);
            String desc = tokenizer.nextToken();
            //System.out.println("The dest " + desc);
            double price = Double.parseDouble(tokenizer.nextToken());
            //System.out.println("The Price is " + price);
            double quantity = Double.parseDouble(tokenizer.nextToken());
            //System.out.println("The Quantity is " + quantity);

            double ex = Double.parseDouble(tokenizer.nextToken());
            double pac = Double.parseDouble(tokenizer.nextToken());
            double capacity = Double.parseDouble(tokenizer.nextToken());
            //System.out.println("The Capacity is  " + capacity);
            bevList.add(new Beverage(capacity, name, desc, quantity, price, ex, pac));

        } catch (NumberFormatException ex) {
            Logger.getLogger(Beverage.class.getName()).log(Level.WARNING, "error");
        }
    }
    return bevList;
}

Answer 1

If you are only using the ArrayList to read data into and then display it in a JList, then don't use an ArrayList. Instead use a DefaultListModel , fill it with your file's data by calling addElement(...) on it, and then set the JList's model via setModel(...) with your data-filled model.

If on the other hand you absolutely must use an ArrayList to hold your data, then I see you having two possible options here:

• Use your ArrayList, but also create a DefaultListModel, and fill the list model with the ArrayList data using a for loop. The down-side, your data will be held in two collections, and there's no guarantee that the data will remain fully synchronized.
• Create an AbstractListModel using your ArrayList as a data nucleus. This would be the cleaner way to do this, but will require more effort on your part, including making sure that you call the proper fireXXX(...) notification methods for instance.

For more details, please see the How to use Lists tutorial.

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Edit Regarding your code, @again, in place of an ArrayList, use a DefaultListModel. Key also will be how your objects display in the JList, and to get this right, you'll need to either give the Beverage class a decent toString() method, or else (and better) you should give the JList a decent ListCellRenderer.