如何在javafx中设置没有空构造函数的控制器？

Question

假设我有这个：

public class selezioneTipoEventoForm {

    @FXML private Button eventoSportivoButton;
    @FXML private Button eventoMusicaleButton;
    @FXML private Button eventoTeatraleButton;
    @FXML private Button eventoCinemaButton;
    private formController cambiaForm;

    public selezioneTipoEventoForm(formController cambiaForm){
        this.cambiaForm=cambiaForm;
    }

    @FXML public void eventoSportivoButtonPressed(ActionEvent e){
        cambiaForm.mostraFormInserisciEvento(tipologiaEnum.SPORTIVO);
    }

这是我的自定义控制器，现在是当我将方法绑定到按钮时出现的FXML文件，出现此错误：

No controller specified for top level element

因为我想稍后使用数据设置控制器，所以我没有在FXML文件中设置控制器，所以在这种情况下，我需要一个名为formController的类，并且在该类中我有以下方法：

private eventoSpecificoForm setControllerEventoSportivo(FXMLLoader loader,datiEventoController controllaDatiEvento) {
    try {
       eventoSportivoForm esf=  new eventoSportivoForm(controllaDatiEvento);
        Node root = loader.load();
        formAggiuntivo.getChildren().add(root);
        loader.setController(esf);
        return esf;
    } catch (Exception e) {}
    return null;
}

有解决方案吗？吓到我了。

编辑：这是给我错误的文件fxml：

<?xml version="1.0" encoding="UTF-8"?>

<?import com.jfoenix.controls.JFXButton?>
<?import javafx.scene.image.Image?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="370.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8.0.171" xmlns:fx="http://javafx.com/fxml/1">
   <children>
      <JFXButton fx:id="eventoSportivoButton" buttonType="RAISED" layoutX="73.0" layoutY="59.0" onAction="#eventoSportivoButtonPressed" prefHeight="100.0" prefWidth="200.0" style="-fx-background-color: #d9663f;" text="Evento Sportivo" textFill="WHITE">
         <graphic>
            <ImageView fitHeight="26.0" fitWidth="39.0" pickOnBounds="true" preserveRatio="true">
               <image>
                  <Image url="@../icons/icons8-soccer-ball-64.png" />
               </image>
            </ImageView>
         </graphic>
      </JFXButton>
      <JFXButton fx:id="eventoMusicaleButton" buttonType="RAISED" layoutX="273.0" layoutY="59.0" prefHeight="100.0" prefWidth="200.0" style="-fx-background-color: #3fd9a5;" text="Evento Musicale" textFill="WHITE">
         <graphic>
            <ImageView fitHeight="26.0" fitWidth="39.0" pickOnBounds="true" preserveRatio="true">
               <image>
                  <Image url="@../icons/icons8-musical-64.png" />
               </image>
            </ImageView>
         </graphic>
      </JFXButton>
      <JFXButton fx:id="eventoTeatraleButton" buttonType="RAISED" layoutX="73.0" layoutY="159.0" prefHeight="100.0" prefWidth="200.0" style="-fx-background-color: #3f78da;" text="Evento Teatrale" textFill="WHITE">
         <graphic>
            <ImageView fitHeight="26.0" fitWidth="39.0" pickOnBounds="true" preserveRatio="true">
               <image>
                  <Image url="@../icons/icons8-theatre-mask-64.png" />
               </image>
            </ImageView>
         </graphic>
      </JFXButton>
      <JFXButton fx:id="eventoCinemaButton" buttonType="RAISED" layoutX="273.0" layoutY="159.0" prefHeight="100.0" prefWidth="200.0" style="-fx-background-color: #da3e3e;" text="Cinema" textFill="WHITE">
         <graphic>
            <ImageView fitHeight="26.0" fitWidth="39.0" pickOnBounds="true" preserveRatio="true">
               <image>
                  <Image url="@../icons/icons8-film-reel-64.png" />
               </image>
            </ImageView>
         </graphic>
      </JFXButton>
   </children>
</AnchorPane>

此行：

<JFXButton fx:id="eventoSportivoButton" buttonType="RAISED" layoutX="73.0" layoutY="59.0" onAction=**"#eventoSportivoButtonPressed**" prefHeight="100.0" prefWidth="200.0" style="-fx-background-color: #d9663f;" text="Evento Sportivo" textFill="WHITE">
     <graphic>

“未为顶级元素指定控制器”