Hi,
I'm quite new to JavaFX. I've tried creating a custom control, extending a GridPane, similarly to the one in this tutorial. I've tried inserting the control in the FXML layout of an application, and it seems to work fine. However, when I try to import into Scene Builder 2.0 a jar file containing my control, it doesn't appear in the list of elements to import (unlike some other controls in the same jar). f I select "Show JAR Analysis Report", it shows an error caused by "javafx.fxml.LoadException: Root value already specified".
My controller has an fxml layout with an fx:root root element, and one java class which sets itself as the root and loads the fxml in its constructor.
Do you have any idea why this controller would work in a real application but not import in Scene Builder?
I have posted my code on Stackoverflow but I'll also copy it here too.
Here is the FXML :
<?xml version="1.0" encoding="UTF-8"?>
<?import javafx.scene.control.*?>
<?import javafx.scene.image.ImageView?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.text.Font?>
<fx:root type="javafx.scene.layout.GridPane" id="MediaMetadataDisplay" hgap="20.0" maxHeight="-Infinity" maxWidth="-Infinity" minHeight="-Infinity" minWidth="-Infinity" prefHeight="200.0"
prefWidth="600.0" xmlns="http://javafx.com/javafx/8" xmlns:fx="http://javafx.com/fxml/1">
<columnConstraints>
<ColumnConstraints fillWidth="false" hgrow="NEVER" maxWidth="-Infinity" minWidth="-Infinity" prefWidth="200.0"/>
<ColumnConstraints halignment="LEFT" hgrow="ALWAYS"/>
</columnConstraints>
<rowConstraints>
<RowConstraints maxHeight="-Infinity" minHeight="-Infinity" prefHeight="30.0" vgrow="SOMETIMES"/>
<RowConstraints maxHeight="-Infinity" minHeight="-Infinity" prefHeight="40.0" vgrow="SOMETIMES"/>
<RowConstraints maxHeight="-Infinity" minHeight="-Infinity" prefHeight="25.0" vgrow="SOMETIMES"/>
<RowConstraints maxHeight="-Infinity" minHeight="-Infinity" prefHeight="25.0" vgrow="SOMETIMES"/>
<RowConstraints maxHeight="-Infinity" minHeight="-Infinity" prefHeight="25.0" vgrow="SOMETIMES"/>
<RowConstraints maxHeight="-Infinity" minHeight="-Infinity" prefHeight="25.0" vgrow="SOMETIMES"/>
<RowConstraints maxHeight="-Infinity" minHeight="-Infinity" prefHeight="30.0" vgrow="SOMETIMES"/>
</rowConstraints>
<children>
<ImageView id="coverView" fx:id="coverView" fitHeight="200.0" fitWidth="200.0" pickOnBounds="true" preserveRatio="true" GridPane.rowSpan="7"/>
<Label id="trackName" fx:id="trackName" maxWidth="1.7976931348623157E308" text="trackName" GridPane.columnIndex="1" GridPane.rowIndex="1">
<font>
<Font name="System Bold" size="16.0"/>
</font>
</Label>
<Label id="artist" fx:id="artist" maxWidth="1.7976931348623157E308" text="artist" GridPane.columnIndex="1" GridPane.rowIndex="2"/>
<Label id="album" fx:id="album" maxWidth="1.7976931348623157E308" text="album" GridPane.columnIndex="1" GridPane.rowIndex="3"/>
<Label id="genre" fx:id="genre" maxWidth="1.7976931348623157E308" text="genre" GridPane.columnIndex="1" GridPane.rowIndex="4"/>
<Label id="trackNumber" fx:id="trackNumber" maxWidth="1.7976931348623157E308" text="trackNumber" GridPane.columnIndex="1" GridPane.rowIndex="5"/>
</children>
</fx:root>
And the Java controller/root element:
package customjavafx.scene.control;
import javafx.beans.property.ObjectProperty;
import javafx.beans.property.SimpleObjectProperty;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;
import javafx.scene.control.Label;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.GridPane;
import javafx.scene.media.Media;
import java.io.IOException;
import java.util.Map;
public class MediaMetadataDisplay extends GridPane {
public MediaMetadataDisplay() {
final FXMLLoader fxmlLoader = new FXMLLoader(getClass().getResource("MediaMetadataDisplay.fxml"));
fxmlLoader.setRoot(this);
fxmlLoader.setController(this);
try {
fxmlLoader.load();
} catch (IOException exception) {
throw new RuntimeException(exception);
}
media.addListener((obs, oldVal, newVal) -> updateMedia(newVal));
}
private final ObjectProperty<Media> media = new SimpleObjectProperty<>((Media) null, "media");
@FXML private ImageView coverView;
@FXML private Label trackName;
@FXML private Label artist;
@FXML private Label album;
@FXML private Label genre;
@FXML private Label trackNumber;
public void updateMedia(Media media) {
// TODO show updated metadata
}
public ObjectProperty<Media> mediaProperty() {
return media;
}
public Media getMedia() {
return mediaProperty().get();
}
public void setMedia(final Media media) {
mediaProperty().set(media);
}
}
The cause of the error, in the stacktrace shown by Scene Builder :
Caused by: javafx.fxml.LoadException: Root value already specified.
file:/Users/guillaumegaly/Library/Application%20Support/Scene%20Builder/Library/custom-controls_2.11.jar!/customjavafx/scene/control/MediaMetadataDisplay.fxml
at javafx.fxml.FXMLLoader.constructLoadException(FXMLLoader.java:2613)
at javafx.fxml.FXMLLoader.createElement(FXMLLoader.java:2771)
at javafx.fxml.FXMLLoader.processStartElement(FXMLLoader.java:2720)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2527)
at javafx.fxml.FXMLLoader.loadImpl(FXMLLoader.java:2441)
at javafx.fxml.FXMLLoader.load(FXMLLoader.java:2409)
at customjavafx.scene.control.MediaMetadataDisplay.<init>(MediaMetadataDisplay.java:26)
... 18 more