RichTextFx: How to add binding to StyleClassedTextArea - javafx

Question

Forgive me if what I ask is obvious but I can't figure out how to create a binding in a StyleClassedTextArea, using RichTextFx. What I want to do is to have the area and a button (that will trigger text-processing of some kind) and disable the button if the area is empty.
My code is the following
Main.java
package application;
import javafx.application.Application;
import javafx.fxml.FXMLLoader;
import javafx.stage.Stage;
import javafx.scene.Parent;
import javafx.scene.Scene;
public class Main extends Application {
#Override
public void start(Stage primaryStage) {
try {
Parent root = FXMLLoader.load(getClass().getResource("Main.fxml"));
Scene scene = new Scene(root);
scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
primaryStage.setScene(scene);
primaryStage.show();
} catch(Exception e) {
e.printStackTrace();
}
}
public static void main(String[] args) {
launch(args);
}
}
Controller.java
package application;
import java.net.URL;
import java.util.ResourceBundle;
import org.fxmisc.richtext.StyleClassedTextArea;
import javafx.beans.binding.Bindings;
import javafx.beans.value.ObservableStringValue;
import javafx.fxml.FXML;
import javafx.fxml.Initializable;
import javafx.scene.control.Button;
public class Controller implements Initializable {
#FXML private StyleClassedTextArea mainArea;
#FXML private Button processButton;
#Override
public void initialize(URL arg0, ResourceBundle arg1) {
// TODO Auto-generated method stub
processButton.disableProperty().bind(Bindings.isEmpty((ObservableStringValue) mainArea.textProperty()));
}
}
Main.fxml
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.Button?>
<?import javafx.scene.layout.AnchorPane?>
<?import javafx.scene.layout.VBox?>
<?import org.fxmisc.richtext.StyleClassedTextArea?>
<AnchorPane prefHeight="308.0" prefWidth="291.0" xmlns:fx="http://javafx.com/fxml/1" xmlns="http://javafx.com/javafx/8.0.60" fx:controller="application.Controller">
<children>
<VBox layoutY="6.0" prefHeight="308.0" prefWidth="291.0" AnchorPane.bottomAnchor="0.0" AnchorPane.leftAnchor="0.0" AnchorPane.rightAnchor="0.0" AnchorPane.topAnchor="0.0">
<children>
<StyleClassedTextArea fx:id="mainArea" />
<Button fx:id="processButton" mnemonicParsing="false" text="process" />
</children>
</VBox>
</children>
</AnchorPane>
and this because mainTextArea.textProperty() returns ObservableValue<String> when I cast it throws an exception with the following stack trace
javafx.fxml.LoadException:
/C:/Users/dcg601/workspace/javafx/bin/application/Main.fxml
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2601)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2579)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3214)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3175)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3148)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3124)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:3104)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:3097)
at application.Main.start(Main.java:22)
at com.sun.javafx.application.LauncherImpl.lambda$launchApplication1$162(LauncherImpl.java:863)
at com.sun.javafx.application.PlatformImpl.lambda$runAndWait$175(PlatformImpl.java:326)
at com.sun.javafx.application.PlatformImpl.lambda$null$173(PlatformImpl.java:295)
at java.security.AccessController.doPrivileged(Native Method)
at com.sun.javafx.application.PlatformImpl.lambda$runLater$174(PlatformImpl.java:294)
at com.sun.glass.ui.InvokeLaterDispatcher$Future.run(InvokeLaterDispatcher.java:95)
at com.sun.glass.ui.win.WinApplication._runLoop(Native Method)
at com.sun.glass.ui.win.WinApplication.lambda$null$148(WinApplication.java:191)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.ClassCastException: org.reactfx.value.SuspendableValWrapper cannot be cast to javafx.beans.value.ObservableStringValue
at application.Controller.initialize(Controller.java:20)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2548)
... 17 more

Answer 1

It's crazy but it works:
#Override
public void initialize(URL arg0, ResourceBundle arg1) {
// TODO Auto-generated method stub
ObservableValue<String> qwer = mainArea.textProperty();
ObservableStringValue qwerQ = new ObservableStringValue() {
public String get() { return qwer.getValue(); }
public String getValue() { return qwer.getValue(); }
public void addListener( InvalidationListener listener ) {
qwer.addListener( listener );
}
public void removeListener( InvalidationListener listener ) {
qwer.removeListener( listener );
}
public void addListener( ChangeListener<? super String> listener ) {
qwer.addListener( listener );
}
public void removeListener( ChangeListener<? super String> listener ) {
qwer.removeListener( listener );
}
};
processButton.disableProperty().bind(Bindings.isEmpty( qwerQ ) );
}
But probably better to add a simple listeners:
mainArea.textProperty().addListener( ( ov, oldv, newv ) -> {
processButton.setDisable( newv.isEmpty() );
});