如何在黑莓手机中连续播放音频文件？

Question

我设法在黑莓中创建一个播放音频文件的应用程序，但它只能播放一个文件。我尝试使用 for 循环来播放一些音频文件。

我设法播放它，但它没有播放音频文件的整个声音，它只播放第一个音频文件和第二个音频文件几秒钟，然后停止播放。播放的文件也会播放相互重叠的声音，这是不应该发生的。

如何在黑莓手机中不间断地连续播放音频文件的完整声音？

这是我使用 for 循环创建的应用程序的代码：

    package mypackage;

import javax.microedition.media.Manager;
import javax.microedition.media.MediaException;
import javax.microedition.media.Player;
import java.lang.Class;
import javax.microedition.rms.RecordStore;
import java.io.InputStream;
import java.io.ByteArrayInputStream;
import net.rim.device.api.media.protocol.ByteArrayInputStreamDataSource;
import net.rim.device.api.system.*;
import net.rim.device.api.ui.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.extension.container.*;
import net.rim.device.api.ui.UiApplication;
import java.io.IOException;

public class PlayMedia extends UiApplication{
    /**
     * Entry point for application
     * @param args Command line arguments (not used)
     */ 
    public static void main(String[] args){

        PlayMedia theApp = new PlayMedia();
        theApp.enterEventDispatcher();
    }

    public PlayMedia()
    {

        pushScreen(new PlayMediaScreen());


    }
    /**
     * A class extending the MainScreen class, which provides default standard
     * behavior for BlackBerry GUI applications.
     */
    final class PlayMediaScreen extends MainScreen
    {
        /**
         * Creates a new PlayMediaScreen object
         */
        PlayMediaScreen()
        {
            String test1 = "Test(2seconds).mp3";
            String test2 = "Test(2seconds)2.mp3";
            String test3 = "Test(2seconds)3.mp3";
            String test4 = "Test(2seconds)4.mp3";
            String test5 = "blind_willie.mp3";
            String mp3 = null;

            for(int i=0;i<5;i++){
                if(i == 0){
                    mp3 = test1;
                }
                else if(i == 1){
                    mp3 = test2;
                }
                else if(i == 2){
                    mp3 = test3;
                }
                else if(i == 3){
                    mp3 = test4;
                }
                else if(i == 4){
                    mp3 = test5;
                }
                play(mp3);
            }
        }

        private void play(String mp3){

        Player p = null;

        InputStream stream = (InputStream)this.getClass().getResourceAsStream("/" + mp3);

            try {
                //p = Manager.createPlayer(source);
                p = Manager.createPlayer(stream, "audio/mpeg");
                p.realize();
                p.prefetch();

                //testing
                System.out.println("Creating Players!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
                System.out.println("The mp3 is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();

                //testing
                System.out.println("IO Exeception!!!!!!!!!!!!!!!!1 " + e);

                //testing 
                System.out.println(p);

            } catch (MediaException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();

            //testing
            System.out.println("Media Exeception!!!!!!!!!!!!!!!!1" + e);

            //testing 
            System.out.println(p);
            }
            /*
             * Best practice is to invoke realize(), then prefetch(), then start().
             * Following this sequence reduces delays in starting media playback.
             *
             * Invoking start() as shown below will cause start() to invoke  prefetch(0),
             * which invokes realize() before media playback is started.
             */
            try {
                p.start();
            } catch (MediaException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();

                //testing
                System.out.println("Media Exeception for starting!!!!!!!!!!!!!!!!1" + e);

                //testing 
                System.out.println(p);
            }

            /*try {
                p.stop();
            } catch (MediaException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }*/
            //p.deallocate();
            //p.close();



        }
    }
} 

Answer 1

我成功播放了它，但它没有播放音频文件的整个声音，它只播放第一个音频文件和第二个音频文件几秒钟，然后停止播放。播放的文件也会播放相互重叠的声音，这是不应该发生的。

请重新阅读 BB API 文档 玩家仔细：

简单播放

可以通过 Manager 的 createPlayer 方法之一创建 Player。 Player创建后，调用start会尽快开始播放。当播放开始时该方法将返回。播放将在后台继续，并在到达媒体结尾时自动停止。

简单的播放示例说明了这一点：

try {
    Player p = Manager.createPlayer("http://abc.wav");
    p.start();
} catch (MediaException pe) {
} catch (IOException ioe) {
}

请注意文档说 该方法将在播放开始时返回。播放将在后台继续进行..。这就是你得到“声音重叠”的原因。

为了克服这个问题，您需要将一个侦听器附加到播放器Player.addPlayerListener(PlayerListener playerListener)。当媒体文件播放完时，监听器将从后台“播放”线程收到通知。这将是开始下一个媒体文件的新播放的正确时机。请不要指望我提供代码，我只是给你一个想法。

Answer 2

终于我明白了，这是我的代码。 ：D

package mypackage;

import javax.microedition.media.Manager;
import javax.microedition.media.MediaException;
import javax.microedition.media.Player;
import javax.microedition.media.PlayerListener;

import java.lang.Class;
import javax.microedition.rms.RecordStore;
import java.io.InputStream;
import java.io.ByteArrayInputStream;
import net.rim.device.api.media.protocol.ByteArrayInputStreamDataSource;
import net.rim.device.api.system.*;
import net.rim.device.api.ui.*;
import net.rim.device.api.ui.component.*;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.extension.container.*;
import net.rim.device.api.ui.UiApplication;
import java.io.IOException;

public class PlayMedia extends UiApplication{
    /**
     * Entry point for application
     * @param args Command line arguments (not used)
     */ 
    public static void main(String[] args){

        PlayMedia theApp = new PlayMedia();
        theApp.enterEventDispatcher();
    }

    public PlayMedia()
    {

        pushScreen(new PlayMediaScreen());


    }
    /**
     * A class extending the MainScreen class, which provides default standard
     * behavior for BlackBerry GUI applications.
     */
    final class PlayMediaScreen extends MainScreen implements PlayerListener
    {
        /**
         * Creates a new PlayMediaScreen object
         */
        Player p = null;
        String mp3 = ""; 
        String test1 = "Test2seconds.mp3";
        String test5 = "Test2seconds2.mp3";
        //String test6 = "Test2seconds3.mp3";
        String test4 = "Test2seconds4.mp3";
        String test2 = "blind_willie.mp3";
        String test3 = "blind_willie2.mp3";


        PlayMediaScreen()
        {
            mp3 = test1;
            play(mp3);
        }

        private void play(String mp3){



        InputStream stream = (InputStream)this.getClass().getResourceAsStream("/" + mp3);

            try {
                //p = Manager.createPlayer(source);
                p = Manager.createPlayer(stream,"audio/mpeg");
                p.addPlayerListener(this);
                p.realize();
                p.prefetch();

                //testing
                System.out.println("Creating Players!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");
                System.out.println("The mp3 is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();

                //testing
                System.out.println("IO Exeception!!!!!!!!!!!!!!!!1 " + e);

                //testing 
                System.out.println(p);

            } catch (MediaException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();

            //testing
            System.out.println("Media Exeception!!!!!!!!!!!!!!!!1" + e);

            //testing 
            System.out.println(p);
            }
            /*
             * Best practice is to invoke realize(), then prefetch(), then start().
             * Following this sequence reduces delays in starting media playback.
             *
             * Invoking start() as shown below will cause start() to invoke  prefetch(0),
             * which invokes realize() before media playback is started.
             */
            try {
                p.start();
            } catch (MediaException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();

                //testing
                System.out.println("Media Exeception for starting!!!!!!!!!!!!!!!!1" + e);

                //testing 
                System.out.println(p);
            }
            /*
            try {
                p.stop();
            } catch (MediaException e) {
            // TODO Auto-generated catch block
                e.printStackTrace();
            }
            p.deallocate();
            p.close();
            */


        }

        public void playerUpdate(Player player, String event, Object eventData) {
            // TODO Auto-generated method stub
            if (event.equals(PlayerListener.END_OF_MEDIA)) {

                //String mp3 = ""; 

                if( mp3.equals(test1) ) {
                    mp3 = test2;
                    //testing
                    System.out.println("The MP3 is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                    play(mp3);

                    //testing
                    System.out.println("The MP3 FINISH PLAYING is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                }
                 else if( mp3.equals(test2) ){ 
                     mp3 = test3;
                    //testing
                    System.out.println("The MP3 is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                    play(mp3);

                    //testing
                    System.out.println("The MP3 FINISH PLAYING is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                 }
                 else if( mp3.equals(test3) ) {
                     mp3 = test4;
                     //testing
                    System.out.println("The MP3 is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                    play(mp3);

                    //testing
                    System.out.println("The MP3 FINISH PLAYING is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                 }                   
                 else if( mp3.equals(test4) ) {
                     mp3 = test5;
                    //testing
                    System.out.println("The MP3 is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                    play(mp3);

                    //testing
                    System.out.println("The MP3 FINISH PLAYING is " + mp3 + "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!");

                 }
                 else if( mp3.equals(test5) ){
                     mp3 = null;
                     try {
                        player.stop();
                    } catch (MediaException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                     player.deallocate();
                     player.close();
                 }

              }
        }
    }
}