如何在不使用JavaFX中的控制器类的情况下使用FXML（从接口传递或获取值）？

Question

是否可以在不使用控制器类的情况下从JavaFX中的FXML接口字段传递/获取值？

Answer 1

No, not really.

JavaFX follows an MVC-type architecture. The model is left up to the programmer (with support from JavaFX observable properties): FXML supports the view, and the Java controller is the Controller.

This gives a nice separation between the definition of the layout (the view, in fxml), and the processing logic (the controller, in Java), which follows long-established, proven, industry standard designs. It also keeps the FXML nice and simple, which makes it relatively easy to create Rapid Application Development (RAD) tools, such as SceneBuilder.

That said, there is (at least technically) support for scripting in FXML, though I don't know of any real-world use of this (or even, come to that, any real examples). The FXML documentation has a brief section on scripting , and sure enough the following "works":

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

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

<?language javascript?>

<VBox xmlns:fx="http://javafx.com/fxml/1">
    <children>
        <TextField promptText="Enter a number" fx:id="x" />
        <TextField promptText="Enter another number" fx:id="y" />
        <Button text="Calculate" onAction="sum.text=parseInt(x.text)+parseInt(y.text)"/>
        <Label fx:id="sum" />

    </children>
</VBox>

If you can figure out do something as simple as avoid the "Calculate" button and just update the label as the text in the text fields change, feel free to post it. I don't really think this is a technique that is applicable to any real-world application.

Answer 2

You can use a different pattern if you make a custom root for your fxml with fx:root, this way the "controller" will also be part of the component too like in the pattern Code Behind.

Basically, you extend a component of JavaFX (for instance BorderPane). Then you use it as root of your FXML. To make this work you have to use FXMLLoader's setRoot(...) method and use fx:root in FXML.

Then you can use your custom JavaFX component as a controller too and invoke FXMLLoader in the constructor. As a result you can inject components from your FXML in your custom Java component:

public class MyJavaFXBorderPane extends BorderPane {

@FXML
public TextField textFieldFromFXML;

public MyJavaFXBorderPane() {
    final FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("myfxml.fxml"));
    fxmlLoader.setRoot(this);
    fxmlLoader.setController(this);
}

}

You change the order of loading with this technique: Java component first (which is also a controller) and then FXML instead of FXML first with FXMLLoader and then its controller.

So, of course it is a controller, but also a component which is the root of the fxml, you can override methods, add new fields etc...