JAVA netbeans problems with comboBox

Question

我正在尝试加载2个组合框;第二个组合框必须在第一个组合框更改之后加载。我正在使用netbeans，我尝试了几次，但它不起作用…加载的项目必须是相同的，除了在第一个组合中选择的项目。

    private void firstTeamComboBoxItemStateChanged(java.awt.event.ItemEvent evt)
{                                                   
        loadSecondTeamComboBox();
    }                                                  
    private void loadSecondTeamComboBox()
    {
        String[] theTeamsInTheLeague2 = league.loadTeamsInLeague(secondTeam.getLeague());
        secondTeamComboBox.addItem("Select a Team");
        for(int i = 0; i < theTeamsInTheLeague2.length; i++)
            if (!(theTeamsInLeague2[i].equals(firstTeam.getLeague()))
                secondTeamComboBox.addItem(theTeamsInTheLeague2[i]);
    }

    private void loadFirstTeamComboBox()
    {
        String[] theTeamsInTheLeague1 = league.loadTeamsInLeague(firstTeam.getLeague());
        firstTeamComboBox.addItem("Select a Team");
        for(int i = 0; i < theTeamsInTheLeague1.length; i++)
            firstTeamComboBox.addItem(theTeamsInTheLeague1[i]);
    }

Answer 1

一种方法是在DefaultComboBoxModel中覆盖setSelectedItem()，并保持对otherTeamModel的引用，根据需要从allTeamsInTheLeague更新它。

class MyComboBoxModel extends DefaultComboBoxModel {
    private DefaultComboBoxModel otherTeamModel;
    public MyComboBoxModel(DefaultComboBoxModel otherTeamModel) {
        this.otherTeamModel = otherTeamModel;
    }
    @Override
    public void setSelectedItem(Object item) {
        super.setSelectedItem(item);
        otherTeamModel.removeAllElements();
        // add all allTeamsInTheLeague except item
    }
}