Playing audio using JavaFX MediaPlayer in a normal

Question

I need to be able to play Audio files (MP3 / Wav) in a normal Java project. I'd prefer using the new JavaFX MediaPlayer rather than JMF. I wrote some code to test this:

public void play()
{
    URL thing = getClass().getResource("mysound.wav");
    Media audioFile = new Media( thing.toString() );     
    try
    {                                       
        MediaPlayer player = new MediaPlayer(audioFile);
        player.play();
    }
    catch (Exception e)
    {
        System.out.println( e.getMessage() );
        System.exit(0);
    }        
}

When I run this, I get the exception: Toolkit not initialized

I get that this has something to do with the JavaFX thread. My question is, how can I solve this? Do I need to create a JavaFX Panel just to play some audio files in the background of my normal app, or is there any other way?

Edit: Stacktrace:

java.lang.IllegalStateException: Toolkit not initialized
    at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:121)
    at com.sun.javafx.application.PlatformImpl.runLater(PlatformImpl.java:116)
    at javafx.application.Platform.runLater(Platform.java:52)
    at javafx.scene.media.MediaPlayer.init(MediaPlayer.java:445)
    at javafx.scene.media.MediaPlayer.<init>(MediaPlayer.java:360)
    at javaapplication6.JavaApplication6.play(JavaApplication6.java:23)
    at javaapplication6.JavaApplication6.main(JavaApplication6.java:14)

Answer 1

Use a JFXPanel and be careful to only use JavaFX objects on the JavaFX thread and after the JavaFX system has been properly initialized.

JavaFX is normal Java which makes the question a bit confusing, but I guess you mean Swing.

Here's a sample audio player which is launched from . The sample assumes that there are a bunch of mp3 files in the default public sample music folder for Windows 7 (C:\Users\Public\Music\Sample Music) and plays each file in turn.

import java.io.*;
import java.util.*;
import javafx.application.Platform;
import javafx.beans.value.*;
import javafx.embed.swing.JFXPanel;
import javafx.event.*;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.*;
import javafx.scene.layout.*;
import javafx.scene.media.*;
import javafx.util.Duration;
import javax.swing.*;

/** Example of playing all mp3 audio files in a given directory 
 * using a JavaFX MediaView launched from Swing 
 */
public class JavaFXVideoPlayerLaunchedFromSwing {
  private static void initAndShowGUI() {
    // This method is invoked on Swing thread
    JFrame frame = new JFrame("FX");
    final JFXPanel fxPanel = new JFXPanel();
    frame.add(fxPanel);
    frame.setBounds(200, 100, 800, 250);
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    frame.setVisible(true);

    Platform.runLater(new Runnable() {
      @Override public void run() {
        initFX(fxPanel);        
      }
    });
  }

  private static void initFX(JFXPanel fxPanel) {
    // This method is invoked on JavaFX thread
    Scene scene = new SceneGenerator().createScene();
    fxPanel.setScene(scene);
  }

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
      @Override public void run() {
        initAndShowGUI();
      }
    });
  }
}

class SceneGenerator {    
  final Label currentlyPlaying = new Label();
  final ProgressBar progress = new ProgressBar();
  private ChangeListener<Duration> progressChangeListener;

  public Scene createScene() {
    final StackPane layout = new StackPane();

    // determine the source directory for the playlist
    final File dir = new File("C:\\Users\\Public\\Music\\Sample Music");
    if (!dir.exists() || !dir.isDirectory()) {
      System.out.println("Cannot find video source directory: " + dir);
      Platform.exit();
      return null;
    }

    // create some media players.
    final List<MediaPlayer> players = new ArrayList<MediaPlayer>();
    for (String file : dir.list(new FilenameFilter() {
      @Override public boolean accept(File dir, String name) {
        return name.endsWith(".mp3");
      }
    })) players.add(createPlayer("file:///" + (dir + "\\" + file).replace("\\", "/").replaceAll(" ", "%20")));
    if (players.isEmpty()) {
      System.out.println("No audio found in " + dir);
      Platform.exit();
      return null;
    }    

    // create a view to show the mediaplayers.
    final MediaView mediaView = new MediaView(players.get(0));
    final Button skip = new Button("Skip");
    final Button play = new Button("Pause");

    // play each audio file in turn.
    for (int i = 0; i < players.size(); i++) {
      final MediaPlayer player     = players.get(i);
      final MediaPlayer nextPlayer = players.get((i + 1) % players.size());
      player.setOnEndOfMedia(new Runnable() {
        @Override public void run() {
          player.currentTimeProperty().removeListener(progressChangeListener);
          mediaView.setMediaPlayer(nextPlayer);
          nextPlayer.play();
        }
      });
    }

    // allow the user to skip a track.
    skip.setOnAction(new EventHandler<ActionEvent>() {
      @Override public void handle(ActionEvent actionEvent) {
        final MediaPlayer curPlayer = mediaView.getMediaPlayer();
        MediaPlayer nextPlayer = players.get((players.indexOf(curPlayer) + 1) % players.size());
        mediaView.setMediaPlayer(nextPlayer);
        curPlayer.currentTimeProperty().removeListener(progressChangeListener);
        curPlayer.stop();
        nextPlayer.play();
      }
    });

    // allow the user to play or pause a track.
    play.setOnAction(new EventHandler<ActionEvent>() {
      @Override public void handle(ActionEvent actionEvent) {
        if ("Pause".equals(play.getText())) {
          mediaView.getMediaPlayer().pause();
          play.setText("Play");
        } else {
          mediaView.getMediaPlayer().play();
          play.setText("Pause");
        }
      }
    });

    // display the name of the currently playing track.
    mediaView.mediaPlayerProperty().addListener(new ChangeListener<MediaPlayer>() {
      @Override public void changed(ObservableValue<? extends MediaPlayer> observableValue, MediaPlayer oldPlayer, MediaPlayer newPlayer) {
        setCurrentlyPlaying(newPlayer);
      }
    });

    // start playing the first track.
    mediaView.setMediaPlayer(players.get(0));
    mediaView.getMediaPlayer().play();
    setCurrentlyPlaying(mediaView.getMediaPlayer());

    // silly invisible button used as a template to get the actual preferred size of the Pause button.
    Button invisiblePause = new Button("Pause");
    invisiblePause.setVisible(false);
    play.prefHeightProperty().bind(invisiblePause.heightProperty());
    play.prefWidthProperty().bind(invisiblePause.widthProperty());

    // layout the scene.
    layout.setStyle("-fx-background-color: cornsilk; -fx-font-size: 20; -fx-padding: 20; -fx-alignment: center;");
    layout.getChildren().addAll(
      invisiblePause,
      VBoxBuilder.create().spacing(10).alignment(Pos.CENTER).children(
        currentlyPlaying,
        mediaView,
        HBoxBuilder.create().spacing(10).alignment(Pos.CENTER).children(skip, play, progress).build()
      ).build()
    );
    progress.setMaxWidth(Double.MAX_VALUE);
    HBox.setHgrow(progress, Priority.ALWAYS);
    return new Scene(layout, 800, 600);
  }

  /** sets the currently playing label to the label of the new media player and updates the progress monitor. */
  private void setCurrentlyPlaying(final MediaPlayer newPlayer) {
    progress.setProgress(0);
    progressChangeListener = new ChangeListener<Duration>() {
      @Override public void changed(ObservableValue<? extends Duration> observableValue, Duration oldValue, Duration newValue) {
        progress.setProgress(1.0 * newPlayer.getCurrentTime().toMillis() / newPlayer.getTotalDuration().toMillis());
      }
    };
    newPlayer.currentTimeProperty().addListener(progressChangeListener);

    String source = newPlayer.getMedia().getSource();
    source = source.substring(0, source.length() - ".mp4".length());
    source = source.substring(source.lastIndexOf("/") + 1).replaceAll("%20", " ");
    currentlyPlaying.setText("Now Playing: " + source);
  }

  /** @return a MediaPlayer for the given source which will report any errors it encounters */
  private MediaPlayer createPlayer(String aMediaSrc) {
    System.out.println("Creating player for: " + aMediaSrc);
    final MediaPlayer player = new MediaPlayer(new Media(aMediaSrc));
    player.setOnError(new Runnable() {
      @Override public void run() {
        System.out.println("Media error occurred: " + player.getError());
      }
    });
    return player;
  }
}

Will my .JAR file built via swing automatically have JavaFX added to it once I add it to the libraries in netbeans?

Technically, Swing doesn't build Jar files but the jar of javafx packaging commands do.

If your app contains JavaFX, then, it's best to use the JavaFX packaging tools. Without them, you may have some deployment issues issues as the Java runtime jar (jfxrt.jar) is not automatically on the java boot classpath for jdk7u7. Users can manually add it to their runtime classpath, but it could be a bit of a pain. In future jdk versions (perhaps jdk7u10 or jdk8), jfxrt.jar will be on the classpath. Even then, use of the JavaFX packaging tools would still be recommended as it will be the best way to ensure that your deployment package will work in the most compatible way.

The SwingInterop NetBeans project is a sample NetBeans project which utilizes JavaFX deployment tools for a Swing project embedding JavaFX components. Source for SwingInterop is part of the JDK 7 and JavaFX Demos and Samples download.