从单独的类访问TextField

Question

I am currently attempting to make a very basic class MyController, which takes the content of a TextField in an FXML created window and, when the button in the window is pressed, inserts its contents into a string which is printed to the terminal. Once this is done, it changes the contents of the TextField to "done!".

The code for the FXML file is as follows:

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

<?import javafx.scene.control.*?>
<?import java.lang.*?>
<?import javafx.scene.layout.*?>

<AnchorPane maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="400.0" prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1" fx:controller="practice1.MyController">
   <children>
<Button fx:id="HelloWorld" layoutX="30.0" layoutY="34.0" mnemonicParsing="false" onAction="#sayHello" text="Hello World" />
      <TextField fx:id="message" layoutX="30.0" layoutY="77.0" />
   </children>
</AnchorPane>

The only information of interest in this is that the TextField has the fx:id "message".

The code for my class MyController is as follows:

package practice1;

import javafx.event.*;
import javafx.scene.control.TextField;

public class MyController {

    private TextField message;

    public void sayHello(ActionEvent event) {

        System.out.print("You said \"");
        System.out.print(message.getText());
        System.out.println("\"");
        message.setText("done!");
    }
}

Answer 1

Your TextField in the controller is private so the loader cannot access it. Using javafx.fxml.FXML annotation as follows you can mark it as accessible to FXML.

@FXML
private TextField message;

You could alternatively just declare it as public.