"no injectable field found in fxml controller class for the id" - javafx

Question

SceneBuilder is not injecting fields from controller class to FXML despite being annotated by #FXML. Instead when I enter the ID in fx:id on Scene Builder the error message ""no injectable field found in fxml controller class for the id" is instead shown.
I have managed to get it working in the past, where the ID shows a drop down menu and you simply select the appropriate field; however I'm unsure why it has stopped working.
FXML:
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.control.DatePicker?>
<?import javafx.scene.control.TextField?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.text.Font?>
<?import javafx.scene.text.Text?>
<AnchorPane id="AnchorPane" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" stylesheets="#../../common/gui/common_style.css" xmlns="http://javafx.com/javafx/8.0.111" xmlns:fx="http://javafx.com/fxml/1" fx:controller="vehicles.logic.addVehicle">
<children>
<Text fill="WHITE" layoutX="304.0" layoutY="263.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Registration Number">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="305.0" layoutY="162.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Model">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="307.0" layoutY="215.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Make">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="306.0" layoutY="314.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Engine Size">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="307.0" layoutY="363.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Fuel Type">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="308.0" layoutY="415.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Colour">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="306.0" layoutY="472.0" strokeType="OUTSIDE" strokeWidth="0.0" text="MOT Renewal Date">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="307.0" layoutY="536.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Last Service Date">
<font>
<Font size="19.0" />
</font></Text>
<Text fill="WHITE" layoutX="309.0" layoutY="597.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Current Mileage">
<font>
<Font size="19.0" />
</font></Text>
<TextField fx:id="model" layoutX="538.0" layoutY="142.0" prefHeight="25.0" prefWidth="170.0" />
<TextField fx:id="make" layoutX="539.0" layoutY="195.0" prefHeight="25.0" prefWidth="170.0" />
<TextField fx:id="regnum" layoutX="540.0" layoutY="244.0" prefHeight="25.0" prefWidth="170.0" />
<TextField fx:id="engine" layoutX="539.0" layoutY="295.0" prefHeight="25.0" prefWidth="170.0" />
<TextField fx:id="fueltype" layoutX="540.0" layoutY="344.0" prefHeight="25.0" prefWidth="170.0" />
<TextField fx:id="colour" layoutX="540.0" layoutY="396.0" prefHeight="25.0" prefWidth="170.0" />
<TextField fx:id="mileage" layoutX="540.0" layoutY="577.0" prefHeight="25.0" prefWidth="170.0" />
<DatePicker fx:id="motrenewal" layoutX="539.0" layoutY="453.0" />
<DatePicker fx:id="servicedate" layoutX="541.0" layoutY="515.0" />
<Button fx:id="add" layoutX="927.0" layoutY="604.0" mnemonicParsing="false" prefHeight="26.0" prefWidth="71.0" text="Add" />
<Button fx:id="back" layoutX="820.0" layoutY="604.0" mnemonicParsing="false" prefHeight="25.0" prefWidth="71.0" text="Back" />
<Text fill="WHITE" layoutX="527.0" layoutY="90.0" strokeType="OUTSIDE" strokeWidth="0.0" text="Add Vehicle">
<font>
<Font size="43.0" />
</font>
</Text>
</children>
</AnchorPane>
Controller:
package vehicles.logic;
import java.net.URL;
import java.util.ResourceBundle;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
import javafx.scene.control.DatePicker;
import javafx.scene.control.TextField;
/**
* FXML Controller class
*
* #author ugonw
*/
public class addVehicle implements Initializable {
#FXML
private TextField model;
#FXML
private TextField make;
#FXML
private TextField regnum;
#FXML
private TextField engine;
#FXML
private TextField fueltype;
#FXML
private TextField colour;
#FXML
private TextField mileage;
#FXML
private DatePicker motrenewal;
#FXML
private DatePicker servicedate;
#FXML
private Button add;
#FXML
private Button back;
/**
* Initializes the controller class.
*/
#Override
public void initialize(URL url, ResourceBundle rb) {
// TODO
}
}

Answer 1

a workaround is to open the xml file in your IDE and manually adding the id name to that file. So if Scenebuilder hasen't done this for you and the object concerns a textfield for example, then the tag will look like this.
<TextField />
You should add the fx:id="your_id_name" to it like this:
<TextField fx:id="userName" />
It should work like a charm after saving the xml file. Hope this helps.