JavaFX abstract controller inheritance didn't work - javafx

Question

I have a big problem while coding my application.
Well, I try to extend my ReaderController class, which is abstract and it is set as controller in my fxml file.
There is my code:
public abstract class ReaderController extends AnchorPane{
#FXML
TextField id;
#FXML
TextField name;
#FXML
TextField surname;
#FXML
TextField PESEL;
#FXML
TextField dateOfBirth;
#FXML
TextField documentType;
#FXML
TextField documentNumber;
#FXML
TextField email;
#FXML
TextField phoneNumber;
#FXML
TextField street;
#FXML
TextField city;
#FXML
Button addReader;
Parent root;
public ReaderController()
{
}
And there is my subclass:
public class EditReaderController extends ReaderController{
public EditReaderController() throws IOException
{
FXMLLoader loader = new FXMLLoader(getClass().getResource("/fxml/AddUser.fxml"));
root= (Parent) loader.load();
loader.setController(this);
Stage stage = new Stage();
stage.setTitle("Edit User");
stage.setScene(new Scene(root));
stage.setResizable(false);
stage.show();
}
public void initialize(){
addReader.setText("Edit!");
id.setText(String.valueOf(SQLController.getInstance().getLastIndexOfReader()));
}
I have an error:
aused by: java.lang.InstantiationException
at sun.reflect.InstantiationExceptionConstructorAccessorImpl.newInstance(InstantiationExceptionConstructorAccessorImpl.java:48)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at java.lang.Class.newInstance(Class.java:442)
at sun.reflect.misc.ReflectUtil.newInstance(ReflectUtil.java:51)
at javafx.fxml.FXMLLoader$ValueElement.processAttribute(FXMLLoader.java:927)
... 75 more
So how can I extend my abstract controller into my EditReaderController ?
UPD 1 my fxml file
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.geometry.Insets?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.Label?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.ColumnConstraints?>
<?import javafx.scene.layout.GridPane?>
<?import javafx.scene.layout.HBox?>
<?import javafx.scene.layout.RowConstraints?>
<?import javafx.scene.layout.VBox?>
<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/9" xmlns:fx="http://javafx.com/fxml/1" fx:controller="com.library.controllers.ReaderController">
<children>
<HBox layoutX="151.0" layoutY="64.0" prefHeight="400.0" prefWidth="600.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
<children>
<VBox prefHeight="400.0" prefWidth="129.0">
<children>
<GridPane prefHeight="300.0" prefWidth="129.0">
<columnConstraints>
<ColumnConstraints halignment="CENTER" hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<Label text="Nr czytelnika" />
<Label text="Imię" GridPane.rowIndex="1" />
<Label text="Nazwisko" GridPane.rowIndex="2" />
<Label text="PESEL" GridPane.rowIndex="3" />
<Label text="Data urodzenia" GridPane.rowIndex="4" />
</children>
<VBox.margin>
<Insets top="15.0" />
</VBox.margin>
</GridPane>
</children>
</VBox>
<VBox prefHeight="400.0" prefWidth="178.0">
<children>
<GridPane prefHeight="300.0" prefWidth="178.0">
<columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<TextField fx:id="id" editable="false" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="26.0" prefWidth="34.0" />
<TextField fx:id="name" GridPane.rowIndex="1">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="surname" GridPane.rowIndex="2">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="PESEL" GridPane.rowIndex="3">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="dateOfBirth" editable="false" GridPane.rowIndex="4">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
</children>
<VBox.margin>
<Insets top="15.0" />
</VBox.margin>
</GridPane>
</children>
</VBox>
<VBox prefHeight="200.0" prefWidth="100.0">
<children>
<GridPane prefHeight="300.0" prefWidth="99.0">
<columnConstraints>
<ColumnConstraints halignment="CENTER" hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<Label text="Typ dokumentu" />
<Label text="Nr dokumentu" GridPane.rowIndex="1" />
<Label text="E-mail" GridPane.rowIndex="2" />
<Label text="Nr telefonu" GridPane.rowIndex="3" />
<Label text="Ulica" GridPane.rowIndex="4" />
<Label text="Miasto" GridPane.rowIndex="5" />
</children>
<VBox.margin>
<Insets top="15.0" />
</VBox.margin>
</GridPane>
</children>
</VBox>
<VBox prefHeight="400.0" prefWidth="195.0">
<children>
<GridPane prefHeight="300.0" prefWidth="195.0">
<columnConstraints>
<ColumnConstraints hgrow="SOMETIMES" minWidth="10.0" prefWidth="100.0" />
</columnConstraints>
<rowConstraints>
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
<RowConstraints minHeight="10.0" prefHeight="30.0" vgrow="SOMETIMES" />
</rowConstraints>
<children>
<TextField fx:id="documentType">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="documentNumber" GridPane.rowIndex="1">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="email" GridPane.rowIndex="2">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="phoneNumber" GridPane.rowIndex="3">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="street" GridPane.rowIndex="4">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
<TextField fx:id="city" GridPane.rowIndex="5">
<GridPane.margin>
<Insets right="25.0" />
</GridPane.margin>
</TextField>
</children>
<VBox.margin>
<Insets top="15.0" />
</VBox.margin>
</GridPane>
<Button fx:id="addReader" alignment="CENTER" mnemonicParsing="false" onAction="#onAddReaderAction" text="Dodaj" textAlignment="CENTER">
<VBox.margin>
<Insets left="100.0" top="25.0" />
</VBox.margin>
</Button>
</children>
</VBox>
</children>
</HBox>
</children>
</AnchorPane>

Answer 1

Why are you using an abstract class in your fxml?
Look at this line:
fx:controller="com.library.controllers.ReaderController"
You have a non-abstract subclass. Why not use it?
fx:controller="com.library.controllers.EditReaderController"
Or use your own non-abstract class.
I didn't see any abstract members in ReaderController.
Removing the abstract modifier may also solve this.
Also, it's really confusing that your controller class is extending AnchorPane..
Also, according to #sillyfly in the comments,
there really isn't much use calling setController after the call to FXMLLoader#load, as by this point the fields have been injected... I think it would even raise an exception about the controller already being set...
According to the comment,
I know it, but i didn't know, how to set a new Controller through action ( for example clicked Edit or Add button)
You should first read https://docs.oracle.com/javafx/2/ui_controls/button.htm to know how to run some code when a button is clicked, and run
loader.setController(your new controller);
when your button is clicked, and remove the fx:controller field, because you already set the controller in your logic code.