Java Swing:为 JComboBox 实现我的 Comboboxmodel [英] Java swing: implementing my Comboboxmodel for JComboBox

问题描述

我需要我的组合框来显示组织的简称.问题是我可以在下拉列表中看到组织名称，但不能实际选择它.我的错误在哪里?

I need my combo box to have short names of organizations. The problem is i can see organizations names in dropdown list, but cant actually select it. Where is my mistake?

public class ToComboBoxModel extends AbstractListModel implements ComboBoxModel {
      private String selectedItem;

      private List<Organization> orgs;

      public ToComboBoxModel(List orgs) {
        this.orgs = orgs;
      }

        @Override
      public String getSelectedItem() {

        return selectedItem;
      }

        @Override
      public void setSelectedItem(Object newValue) {
            for (Organization o: orgs){
                if (newValue==o){
                    selectedItem=o.getShortName();
                    break;
                }
            }
      }

        @Override
      public int getSize() {
        return orgs.size();
      }

        @Override
      public String getElementAt(int i) {
        return orgs.get(i).getShortName();
      }
    }

设置模型:

query =session.createQuery("from Organization where isMain = 0");
List orgs=query.list();
toComboBox.setModel(new ToComboBoxModel(orgs));

提前致谢！

推荐答案

我怀疑是您的 setSelectedItem() 方法使用 == 而不是 比较对象.equals()

I suspect it's that your setSelectedItem() method compares objects using == rather than .equals()

考虑使用 DefaultComboBoxModel 已经实现有用的方法.

Consider using a DefaultComboBoxModel which already implements useful methods.

编辑:此外，根据文档，您应该在调用 setSelected 时调用所有已注册的 ListDataListener 对象.

Edit: Also according to the Docs you should be calling all registered ListDataListener objects when setSelected is called.

使用 DefaultComboBoxModel 相当简单.您创建一个新的 DefaultComboBoxModel 添加您希望它包含的元素，然后调用 getSelectedItem() 以检索当前选择的元素.

Using a DefaultComboBoxModel is fairly straightforward. You create a new DefaultComboBoxModel add the elements you want it to contain then call getSelectedItem() to retrieve the element that is currently selected.

这篇关于Java Swing:为 JComboBox 实现我的 Comboboxmodel的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！