How can I show an image using the ImageView component in javafx and fxml?

Question

I suppose it's a very simple thing but I just can't get behind it. All I want is to show an image over an ImageView linked to fxml. Here is my code:

package application;

import java.io.File;

import javafx.application.Application;
import javafx.stage.Stage;
import javafx.scene.Scene;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.AnchorPane;
import javafx.fxml.FXML;
import javafx.fxml.FXMLLoader;


public class Main extends Application
{
    @FXML
    private ImageView imageView;

    @Override
    public void start(Stage primaryStage) 
    {
        try 
        {
        AnchorPane root = (AnchorPane)FXMLLoader.load(getClass().getResource("Sample.fxml"));
        Scene scene = new Scene(root,400,400);
        scene.getStylesheets().add(getClass().getResource("application.css").toExternalForm());
        primaryStage.setTitle("Hello World");

        File file = new File("src/Box13.jpg");
        Image image = new Image(file.toURI().toString());
        imageView = new ImageView(image);

        //root.getChildren().add(imageView);
        primaryStage.setScene(scene);
        primaryStage.show();
    } catch(Exception e) {
        e.printStackTrace();
    }
}

public static void main(String[] args) {
    launch(args);
}
}

And my fxml file

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

<?import java.lang.*?>
<?import javafx.scene.image.*?>
<?import javafx.scene.layout.*?>
<?import javafx.scene.layout.AnchorPane?>

<AnchorPane prefHeight="316.0" prefWidth="321.0" xmlns:fx="http://javafx.com/fxml/1"     xmlns="http://javafx.com/javafx/2.2" fx:controller="application.SampleController">
  <children>
    <ImageView fx:id="imageView" fitHeight="150.0" fitWidth="200.0" layoutX="61.0" layoutY="83.0" pickOnBounds="true" preserveRatio="true" >

    </ImageView>
  </children>
</AnchorPane>

There should be no problem with the file linking as it works fine when I include the outcommented line. This would be the way it's done in java only but I want to use fxml here as I am using fxml for all other components but it just doesn't work for the ImageView and I don't know why. I have also tried to create a new controller class and link the ImageView there but that neither works. Can anyone help me?

Thanks

Answer 1

If you want to use FXML, you should separate the controller (like you were doing with the SampleController). Then your fx:controller in your FXML should point to that.

Probably you are missing the initialize method in your controller, which is part of the Initializable interface. This method is called after the FXML is loaded, so I recommend you to set your image there.

Your SampleController class must be something like this:

public class SampleController implements Initializable {

    @FXML
    private ImageView imageView;

    @Override
    public void initialize(URL location, ResourceBundle resources) {
        File file = new File("src/Box13.jpg");
        Image image = new Image(file.toURI().toString());
        imageView.setImage(image);
    }
}

I tested here and it's working.

Answer 2

You don't need an initializer, unless you're dynamically loading a different image each time. I think doing as much as possible in fxml is more organized. Here is an fxml file that will do what you need.

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

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

<AnchorPane
    xmlns:fx="http://javafx.co/fxml/1"
    xmlns="http://javafx.com/javafx/2.2"
    fx:controller="application.SampleController"
    prefHeight="316.0"
    prefWidth="321.0"
    >
    <children>
        <ImageView
                fx:id="imageView"
                fitHeight="150.0"
                fitWidth="200.0"
                layoutX="61.0"
                layoutY="83.0"
                pickOnBounds="true"
                preserveRatio="true"
            >
            <image>
                <Image
                    url="src/Box13.jpg"
                    backgroundLoading="true"
                    />
            </image>
        </ImageView>
    </children>
</AnchorPane>

Specifying the backgroundLoading property in the Image tag is optional, it defaults to false. It's best to set backgroundLoading true when it takes a moment or longer to load the image, that way a placeholder will be used until the image loads, and the program wont freeze while loading.