java - 如何根据第一个组合框选择过滤第二个组合框中的内容

Question

我想在用户选择本科或研究生时过滤学位。我通过互联网搜索，但找不到带有示例代码的明确答案。

      private String[] itemsUndergraduate = new String[]{"Computer Science", "Software Engineering"};
    private String[] itemsPostgraduate = new String[]{"BA", "Msc"};
private void jComboBox1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
   UPselect.addActionListener(new ActionListener(){
@Override
public void actionPerformed(ActionEvent e){
    String[] itemsUndergraduate = new String[]{"Computer Science", "Software Engineering"};
    String[] itemsPostgraduate = new String[]{"BA", "Msc"};
    String s = (String) UPselect.getSelectedItem();
    if (s.equals("Undergraduate Degrees")){
        //Assign the first list to the combobox
        jComboBox1 = new JComboBox(itemsUndergraduate);
    }
    else{
        //Assign the second list to the combobox
        jComboBox1 = new JComboBox(itemsPostgraduate);
    }
}

});

这是我到目前为止的代码，我该如何解决这个问题？

Answer 1

根据您的评论和更新的代码，是的，您走在正确的道路上。

这是一个例子。首先，我们需要两个列表供以后使用。

String[] itemsUndergraduate = new String[]{"Computer Science", "Software Engineering"};
String[] itemsPostgraduate = new String[]{"BA", "Msc"};

现在，当选择第一个组合框时，我们可以更改第二个组合框的内容以匹配其中一个列表:

UPselect.addActionListener(new ActionListener(){
    @Override
    public void actionPerformed(ActionEvent e){
        String s = (String) UPselect.getSelectedItem();

        //Added this line to help you debug the code
        System.out.print("Does this bit of code ever happen??");
        System.out.print("Value of selected item is: "+s);

        if (s.equals("Undergraduate Degrees")){
            //Assign the first list to the combobox
            jComboBox1 = new JComboBox(itemsUndergraduate);
        }
        else{
            //Assign the second list to the combobox
            jComboBox1 = new JComboBox(itemsPostgraduate);
        }
    }
}