更新 JComboBox [英] Updating JComboBox

问题描述

所以我将 JComboBox 与 ArrayList 一起使用:

So I'm using a JComboBox with an ArrayList:

protected JComboBox<String> jcb;
protected ArrayList<String> favourites;
favourites.add("Favourites");
favourites.add("-0.21 + 0.77");
favourites.add("-0.16 + -0.89");
jcb = new JComboBox(favourites.toArray());

这很好用，我可以选择每个选项并执行我需要执行的选定语句.但是，当我希望更新 JComboBox 时，它不会在我的 GUI 上更新.在我调用的另一种方法中:

This works fine and I can select each option and carry out the selected statements I need to do. However, when I wish to update the JComboBox, it does not update on my GUI. In another method I call:

favourites.add("10 + 4");
jcb.revalidate();
jcb.repaint();

我已经测试过 ArrayList 已经更新(见下文)，但是它没有显示在我的 GUI 上，有什么建议吗?谢谢，

I have Tested that the ArrayList has been updated (see below), however It doesn't show on my GUI, any suggestions? Thanks,

for (String s : favourites)
System.out.println(s);

推荐答案

Swing 基于 MVC 模式.因此使用模型.对模型的更改将自动更新 JComboBox.要更深入地了解一般情况，请阅读 Swing 架构概述 以及针对您的案例 如何使用组合框.

Swing is based on the MVC pattern. Thus use a model. Changes to the model will automatically update the JComboBox. For a deeper understanding in general read Swing Architecture Overview and for your case How to use ComboBoxes.

DefaultComboBoxModel favourites = new DefaultComboBoxModel();
favourites.addElement("Favourites");
favourites.addElement("-0.21 + 0.77");
favourites.addElement("-0.16 + -0.89");
jcb = new JComboBox(favourites);

在另一个 GUI 方法调用中

in the other GUI method call

favourites.addElement("10 + 4");

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