android 扫描SD卡中的所有.mp3文件

我正在尝试扫描 SD 卡中的所有 .mp3 文件并保存其名称。 这是负责此操作的代码片段。 1.我做错了什么？ 1. SD卡 /mnt/sdcard 或 /sdcard 哪个是正确的路径？

public class PlayerActivity extends Activity
{

    public void onCreate(Bundle savedInstanceState)
    {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.player_activity); 
    }
    public class SongsManager 
    {
        // SDCard Path
        //final String MEDIA_PATH = new String(MediaStore.Audio.Media.getContentUri("external").toString());
        private ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();

        public SongsManager()
        {

        }

        public ArrayList<HashMap<String, String>> getPlayList()
        {
         //   File home = new File(MEDIA_PATH);
            File home = Environment.getExternalStorageDirectory();

            if (home.listFiles(new FileExtensionFilter()).length > 0) 
            {

                for (File file : home.listFiles(new FileExtensionFilter())) 
                {
                    HashMap<String, String> song = new HashMap<String, String>();
                    song.put("songTitle", file.getName().substring(0, (file.getName().length() - 4)));
                    song.put("songPath", file.getPath());

                    // Adding each song to SongList
                    songsList.add(song);

                }
            }
            // return songs list array
            return songsList;

        }


        class FileExtensionFilter implements FilenameFilter 
        {
            public boolean accept(File dir, String name) 
            {
                return (name.endsWith(".mp3") || name.endsWith(".MP3"));
            }
        }

    }
}

提前致谢。

尝试这个代码片段

final String MEDIA_PATH = Environment.getExternalStorageDirectory()
        .getPath() + "/";
private ArrayList<HashMap<String, String>> songsList = new ArrayList<HashMap<String, String>>();
private String mp3Pattern = ".mp3";

// Constructor
public SongsManager() {

}

/**
 * Function to read all mp3 files and store the details in
 * ArrayList
 * */
public ArrayList<HashMap<String, String>> getPlayList() {
    System.out.println(MEDIA_PATH);
    if (MEDIA_PATH != null) {
        File home = new File(MEDIA_PATH);
        File[] listFiles = home.listFiles();
        if (listFiles != null && listFiles.length > 0) {
            for (File file : listFiles) {
                System.out.println(file.getAbsolutePath());
                if (file.isDirectory()) {
                    scanDirectory(file);
                } else {
                    addSongToList(file);
                }
            }
        }
    }
    // return songs list array
    return songsList;
}

private void scanDirectory(File directory) {
    if (directory != null) {
        File[] listFiles = directory.listFiles();
        if (listFiles != null && listFiles.length > 0) {
            for (File file : listFiles) {
                if (file.isDirectory()) {
                    scanDirectory(file);
                } else {
                    addSongToList(file);
                }

            }
        }
    }
}

private void addSongToList(File song) {
    if (song.getName().endsWith(mp3Pattern)) {
        HashMap<String, String> songMap = new HashMap<String, String>();
        songMap.put("songTitle",
                song.getName().substring(0, (song.getName().length() - 4)));
        songMap.put("songPath", song.getPath());

        // Adding each song to SongList
        songsList.add(songMap);
    }
}