Hyperlink in JavaFX

Domains: Java

Hyperlink

This chapter tells about the Hyperlink control used to format text as a hyperlink.

The Hyperlink class represents another type of Labeled control. Figure 20-1 demonstrates three states of the default hyperlink implementation.

Figure 20-1 Three States of a Hyperlink Control

Three states of hyperlinks
Description of "Figure 20-1 Three States of a Hyperlink Control"

Creating a Hyperlink

The code fragment that produces a hyperlink is shown in Example 20-1.

Example 20-1 Typical Hyperlink

Hyperlink link = new Hyperlink();
link.setText("http://example.com");
link.setOnAction((ActionEvent e) -> {
    System.out.println("This link is clicked");
});

The setText instance method defines the text caption for the hyperlink. Because the Hyperlink class is an extension of the Labeled class, you can set a specific font and text fill for the hyperlink caption. The setOnAction method sets the specific action, which is called whenever the hyperlink is clicked, similar to how this method works for the Button control. In Example 20-1, this action is limited to printing the string. However, in your application, you might want to implement more common tasks.

Linking the Local Content

The application in Figure 20-2 renders images from the local directory.

Figure 20-2 Viewing Images

Four hypelinks to view images on a local drive.
Description of "Figure 20-2 Viewing Images"



Review the source code of this application shown in Example 20-2.

Example 20-2 Using Hyperlinks to VIew Images

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
 
public class HyperlinkSample extends Application {
 
    final static String[] imageFiles = new String[]{
        "product.png",
        "education.png",
        "partners.png",
        "support.png"
    };
    final static String[] captions = new String[]{
        "Products",
        "Education",
        "Partners",
        "Support"
    };
    final ImageView selectedImage = new ImageView();
    final ScrollPane list = new ScrollPane();
    final Hyperlink[] hpls = new Hyperlink[captions.length];
    final Image[] images = new Image[imageFiles.length];
 
    public static void main(String[] args) {
        Application.launch(args);
    }
 
    @Override
    public void start(Stage stage) {
        Scene scene = new Scene(new Group());
        stage.setTitle("Hyperlink Sample");
        stage.setWidth(300);
        stage.setHeight(200);
 
        selectedImage.setLayoutX(100);
        selectedImage.setLayoutY(10);
 
        for (int i = 0; i < captions.length; i++) {
            final Hyperlink hpl = hpls[i] = new Hyperlink(captions[i]);
            final Image image = images[i] = new Image(
                getClass().getResourceAsStream(imageFiles[i])
            );
            hpl.setOnAction((ActionEvent e) -> {
                selectedImage.setImage(image);
            });
        }
 
        final Button button = new Button("Refresh links");
        button.setOnAction((ActionEvent e) -> {
            for (int i = 0; i < captions.length; i++) {
                hpls[i].setVisited(false);
                selectedImage.setImage(null);
            }
        });
 
        VBox vbox = new VBox();
        vbox.getChildren().addAll(hpls);
        vbox.getChildren().add(button);
        vbox.setSpacing(5);
 
        ((Group) scene.getRoot()).getChildren().addAll(vbox, selectedImage);
        stage.setScene(scene);
        stage.show();
    }
}

This application creates four Hyperlink objects within a for loop. The setOnAction method called on each hyperlink defines the behavior when a user clicks a particular hyperlink. In that case, the corresponding image from the images array is set for the selectedImage variable.

When a user clicks a hyperlink, it becomes visited. You can use the setVisited method of the Hyperlink class to refresh the links. The code fragment in Example 20-3 accomplishes this task.

Example 20-3 Refreshing the HyperlInks

final Button button = new Button("Refresh links");
button.setOnAction((ActionEvent e) -> {
    for (int i = 0; i < captions.length; i++) {
        hpls[i].setVisited(false);
        selectedImage.setImage(null);
    }
});

When clicked, the Refresh Links button brings all the hyperlinks to the unvisited state, as show in Figure 20-3.

Figure 20-3 Unvisited Hyperlinks

The hyperlinks are refreshed.
Description of "Figure 20-3 Unvisited Hyperlinks"



Because the Hyperlink class is an extension of the Labeled class, you can specify not only a text caption but also an image. The application provided in the next section uses both a text caption and an image to create hyperlinks and to load remote HTML pages.

Linking the Remote Content

You can render HTML content in your JavaFX application by embedding the WebView browser in the application scene. The WebView component provides basic web page browsing functionality. It renders web pages and supports user interaction such as navigating links and executing JavaScript commands.

Study the source code of the application in Example 20-4. It creates four hyperlinks with text captions and images. When a hyperlink is clicked, the corresponding value is passed as a URL to the embedded browser.

Example 20-4 Loading Remote Web Pages

import javafx.application.Application;
import javafx.event.ActionEvent;
import javafx.geometry.Pos;
import javafx.scene.*;
import javafx.scene.control.*;
import javafx.scene.image.Image;
import javafx.scene.image.ImageView;
import javafx.scene.layout.HBox;
import javafx.scene.layout.Priority;
import javafx.scene.layout.VBox;
import javafx.scene.text.Font;
import javafx.scene.web.WebEngine;
import javafx.scene.web.WebView;
import javafx.stage.Stage;
 
public class HyperlinkWebViewSample extends Application {
 
    final static String[] imageFiles = new String[]{
        "product.png",
        "education.png",
        "partners.png",
        "support.png"
    };
    final static String[] captions = new String[]{
        "Products",
        "Education",
        "Partners",
        "Support"
    };
 
    final static String[] urls = new String[]{
        "http://www.oracle.com/us/products/index.html",
        "http://education.oracle.com/",
        "http://www.oracle.com/partners/index.html",
        "http://www.oracle.com/us/support/index.html"
    };
    
    final ImageView selectedImage = new ImageView();
    final Hyperlink[] hpls = new Hyperlink[captions.length];
    final Image[] images = new Image[imageFiles.length];   
 
    public static void main(String[] args){
        launch(args);
    }
 
    @Override
    public void start(Stage stage) {
        VBox vbox = new VBox();
        Scene scene = new Scene(vbox);
        stage.setTitle("Hyperlink Sample");
        stage.setWidth(570);
        stage.setHeight(550);
 
        selectedImage.setLayoutX(100);
        selectedImage.setLayoutY(10);
        
        final WebView browser = new WebView();
        final WebEngine webEngine = browser.getEngine();
 
        for (int i = 0; i < captions.length; i++) {
            final Hyperlink hpl = hpls[i] = new Hyperlink(captions[i]);
            final Image image = images[i] =
                new Image(getClass().getResourceAsStream(imageFiles[i]));
            hpl.setGraphic(new ImageView (image));
            hpl.setFont(Font.font("Arial", 14));
            final String url = urls[i];
 
            hpl.setOnAction((ActionEvent e) -> {
                webEngine.load(url);
            });
        }
              
        HBox hbox = new HBox();
        hbox.setAlignment(Pos.BASELINE_CENTER);
        hbox.getChildren().addAll(hpls);
        vbox.getChildren().addAll(hbox, browser);
        VBox.setVgrow(browser, Priority.ALWAYS);
        
        stage.setScene(scene);
        stage.show();
    }
}

The hyperlinks are created within a for loop similar to the one in Example 20-2. The action set for a hyperlink passes the corresponding URL from the urls array to the WebEngine object of the embedded browser.

When you compile and run this application, it produces the window shown in Figure 20-4.

Figure 20-4 Loading Pages from the Oracle Corporate Site

Description of Figure 20-4 follows
Description of "Figure 20-4 Loading Pages from the Oracle Corporate Site"

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