java - 如何在同一个对话框中显示直接输入和排序的ArrayList

Question

任何人都可以帮助我在同一个对话框中打印用户输入和排序的 ArrayList 吗？ (例如，用户输入 = **丰田、马自达、福特**。排序输入 =**福特、马自达、丰田**)。

这是我第一次使用对话框。是否有其他我可以使用的工具，或者我应该在单独的类中编写 Collections.sort(auto); 然后将其插入打印中？

代码如下:

    Scanner in = new Scanner(System.in);
    ArrayList<String> auto = new ArrayList<>();
    boolean done = false;
    do {
        String autoList = JOptionPane.showInputDialog(null, "Enter an Auto you like (q to finish):",
                "click OK for each auto entry");
        if (autoList.equalsIgnoreCase("q")) {
            break;
        }
        auto.add(autoList);
    } while (!done);
    Collections.sort(auto);
    JOptionPane.showMessageDialog(null, "Arra list " + auto
            + "\n Sorted list is " + auto);
    // should print straight user's input on one line and sorted Array list on the second line
    in.close();

Answer 1

问题是，当您调用 Collections.sort(list) 时，列表将被排序，因此当您在消息框中打印 auto 两次时，它打印排序列表两次。另外，返回类型为 void，因此您无法将其连接到字符串的末尾。可以在此处查看示例。

    Scanner in = new Scanner(System.in);
    ArrayList<String> auto = new ArrayList<>();
    boolean done = false;
    do {
        String autoList = JOptionPane.showInputDialog(null, "Enter an Auto you like (q to finish):",
                "click OK for each auto entry");
        if (autoList.equalsIgnoreCase("q")) {
            break;
        }
        auto.add(autoList);
    } while (!done);

    System.out.println("auto: "+ auto);

    Collections.sort(auto);

    System.out.println("auto: "+ auto);

    JOptionPane.showMessageDialog(null, "Arra list " + auto
            + "\n Sorted list is " + auto);
    // should print straight user's input on one line and sorted Array list on the second line
    in.close();

输出:

auto: [Ford, Mazda, Toyota, BMW]
auto: [BMW, Ford, Mazda, Toyota]

当您打印到消息框时，列表已经排序。一种选择是在排序之前复制未排序的列表，以便在排序后您可以引用未排序的值。

以下是如何执行此操作的示例

   Scanner in = new Scanner(System.in);
    ArrayList<String> auto = new ArrayList<>();
    ArrayList<String> unsortedAutos = new ArrayList<>();
    boolean done = false;
    do {
        String autoList = JOptionPane.showInputDialog(null, "Enter an Auto you like (q to finish):",
                "click OK for each auto entry");
        if (autoList.equalsIgnoreCase("q")) {
            break;
        }
        auto.add(autoList);
    } while (!done);


    unsortedAutos = (ArrayList<String>) auto.clone();
    Collections.sort(auto);

    System.out.println("auto: "+ unsortedAutos);
    System.out.println("auto: "+ auto);

    JOptionPane.showMessageDialog(null, "Arra list " + unsortedAutos
            + "\n Sorted list is " + auto);
    // should print straight user's input on one line and sorted Array list on the second line
    in.close();

输出:

auto: [Mazda, Ford, BMW]
auto: [BMW, Ford, Mazda]