Java 每次选择新项目时打印所选组合框项目

我在控制器类中有一个组合框：

public class Controller {

    static String selectedCountry;

    @FXML
    private ResourceBundle resources;

    @FXML
    private URL location;

    @FXML
    private ComboBox<String> comboBoxCountries;

    @FXML
    void initialize() {
        assert comboBoxCountries != null : "fx:id=\"comboBoxCountries\" was not injected: check your FXML file 'app.fxml'.";

        comboBoxCountries.setItems(Main.COUNTRIES);

        selectedCountry = comboBoxCountries.getSelectionModel().getSelectedItem();

    }
}

---

只需将侦听器添加到selected item属性：

ComboxCountries.getSelectionModel（）.selectedItemProperty（）.addListener（（可观察、旧值、新值）->{
System.out.println（newValue）；
});

unrelated：不要对字段（或方法）使用静态作用域，您真正需要它的情况非常罕见（这里的用法当然不属于这些）。

public class Main extends Application {
public static void main(String[] args) {
        launch(args);
 }

    @Override
    public void start(Stage stage) throws Exception {
        System.out.println(Controller.selectedCountry);
        Parent root= FXMLLoader.load(getClass().getResource("/fxml/app.fxml"));
        Scene scene = new Scene(root,1200,900);
        stage.setScene(scene);
        stage.show();
    }