Java 组合框中的项目

当选择组合框中的某个项目时，我将执行和操作，但无论选择哪个项目，它都会执行操作。有人能帮我吗

//number of players combo box
        players = new JComboBox();
        contentPane.add(players, BorderLayout.SOUTH);
        players.addItem("1 Player");
        players.addItem("2 Players");
        players.addActionListener(new ActionListener() {

         @Override
        public void actionPerformed(ActionEvent e) {
         makeFrame();
        }
       });
       players.addItem("3 Players");
//end of combo box

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为了根据所选项目更改行为，您需要在

ActionListener

中检索所选值，并根据所选值更改行为。您可以使用以下内容：

//number of players combo box
//notice that you have to declare players
//as final. If it is a member of the class,
//you can declare it final in the field
//declaration and initialize it in the
//constructor, or if local, just leave it
//as it is here. Unless using Java 8, then it
//doesn't need to be declared final
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("1 Player");
//your combo box still needs to be final
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("1 Player");
players.addItem("2 Players");
players.addItem("3 Players");
players.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        String selectedValue = String.valueOf(players.getSelectedItem());
        if (selectedValue != null && (selectedValue.equals("1 Player") || selectedValue.equals("2 Players"))) {
            makeFrame();
        }
        else {
            //do something else
        }
    }
});
//end of combo box

如果您碰巧提前知道索引（即静态初始化选项列表，而不是动态生成列表），您也可以只参考以下内容检索索引：

//number of players combo box
//the combo box still needs to be final here
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("1 Player");
//your combo box still needs to be final
final JComboBox players = new JComboBox();
contentPane.add(players, BorderLayout.SOUTH);
players.addItem("2 Players");
players.addItem("3 Players");
players.addActionListener(new ActionListener() {
    @Override
    public void actionPerformed(ActionEvent e) {
        int myIndex = players.getSelectedIndex();
        if (myIndex == 0 || myIndex == 1) {
            makeFrame();
        }
        else {
            //do something else
        }
    }
});
//end of combo box

---

你想要什么？如果值为1或2名玩家，您需要调用

makeFrame

。您需要确定选择了哪个项目，并根据该信息执行所需操作。当字段中的选定项发生更改时，将执行ActionPerformed…是的，如果选择了项2，则我希望生成框架（）。。而不仅仅是当其他物品selected@user3507763“项目2”是指列表中的第二个项目（仍然是

“2名玩家”

）还是索引2中的项目（

“3名玩家”

）