Playing sound in Java using java.applet class

Question

I am building a simple program with one button. I want to play the "zvuk.wav" file after I click on the button. It's not working though and I cant solve why. When I click the button, nothing happens. The zvuk.wav file is in the src file with the classes.

Here is my first class which imports java.applet:

    package Music;
import java.net.MalformedURLException;
import java.net.URL;
import java.applet.*;


public class Music {

     private URL soubor;

        public Music(String cesta){
           try {
                soubor = new URL("file:"+cesta);
            } catch (MalformedURLException vyjimka) {
                System.err.println(vyjimka);
            }
            Applet.newAudioClip(soubor).play();
        }


}

MainFram which extends JFrame and has one Button:

package Music;


import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;


public class MainFrame extends JFrame{

public static final int WIDTH = 480;
public static final int HEIGHT = 600;

private String file;



public MainFrame(){
    setSize(WIDTH, HEIGHT);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setVisible(true);
    setTitle("Přehrávač");
    setResizable(false);

    JPanel jPanel = new JPanel();
    JButton bPlay = new JButton("PLAY");


    jPanel.setLayout(null);
    add(jPanel);
    jPanel.add(bPlay);
    bPlay.setBounds(200, 250, 100, 50);


    bPlay.addActionListener(new ActionListener() {

        @Override
        public void actionPerformed(ActionEvent arg0) {
            Music music = new Music("zvuk.wav");

        }
    });

}




public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {

        @Override
        public void run() {
            new MainFrame();
        }
    });
}


}

Answer 1

Please note that Applet.newAudioClip(url).play() does not throw an error if it fails for whatever reason (for example nothing will happen if the project cannot find the wav file).

Try this stand alone test app. Does it work?

import java.applet.Applet;
import java.applet.AudioClip;
import java.net.URL;

public class MainClass {
  public static void main(String[] args) {
    try {
      URL url = new URL("file:zvuk.wav" );
      AudioClip ac = Applet.newAudioClip(url);
      ac.play();

      System.out.println("Press any key to exit.");
      System.in.read();
      ac.stop();
    } catch (Exception e) {
      System.out.println(e);
    }
  }
}

If this small sample works, then it should be a small matter to modify it for your purposes.

However if it doesn't work then we almost certainly know that you project is unable to find the wav file.

Try add this to the code above:

//existing line
URL url = new URL("file:zvuk.wav" );
//new lines to debug wav file location
File myMusicFile = new File(url.getPath());
if(myMusicFile.exists() && !myMusicFile.isDirectory()) { 
    System.out.println("File exists and is not a directory");
}

If the file does not exist then that's your problem, and you need to point your URL to the correct location.

However if the file does exist and it still doesn't work then we have another possible issue outside of code.

• It is possible that .play() is completing too quickly, see below for an example of how to keep it alive.
• It is possible that your wav file is not a type that can be played, or it requires an unsupported codec. This is a far bigger topic and needs a new question, and a little bit of research on your part.

Here is the example to keep it alive from the sample code:

//load and start audio
AudioClip ac = Applet.newAudioClip(url);
ac.play();

System.out.println("Press any key to exit.");
//keep thread alive until a key is pressed
System.in.read();
ac.stop();

---

Sources:

http://www.java2s.com/Code/JavaAPI/java.applet/AppletnewAudioClipURLaudioFileURL.htm

http://docs.oracle.com/javase/7/docs/api/java/applet/AudioClip.html#play%28%29