شناسایی درست پوشه منابع

 class Mp3Filter implements FilenameFilter{
	public boolean accept(File dir, String name){
		return (name.endsWith(".mp3"));
	}
}

public class ringtone extends ListActivity  {
	
	private static final String SD_PATH = new String ("data/data/ir.rojaco.xxxx.xxxx/sound/");
	private List<String> songs = new ArrayList<String>();
	private MediaPlayer mp = new MediaPlayer();
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(layout.ringtone);

        updatePlayList();
        
        ImageButton stopPlay = (ImageButton) findViewById(id.stopbtn);
 
        stopPlay.setOnClickListener(new OnClickListener() {
 
			public void onClick(View arg0) {
				mp.stop();
			}
		});
 
    }
 

 
    @Override
    protected void onListItemClick(ListView list, View view, int position, long id)
    {
    	try{
    		mp.reset();
    		mp.setDataSource(SD_PATH + songs.get(position));
    		mp.prepare();
    		mp.start();
    	} catch (IOException e){
    		Log.v(getString(string.app_name), e.getMessage());
    	}
    }
 
	private void updatePlayList() {
		File home = new File(SD_PATH);
		if(home.listFiles(new Mp3Filter()).length>0){
			for(File file: home.listFiles(new Mp3Filter())){
				songs.add(file.getName());
			}
 
			ArrayAdapter<String> songList = new ArrayAdapter<String>(this, layout.song_item, songs);
			setListAdapter(songList);
		}

    }

قطعه کد ، اما کار نمیکنه!

برای گرفتن نام فایل ها درون فولدر Raw

public List<String> getNameOfAllFileInRawFolder(){
        Field[] fields=R.raw.class.getFields();
List<String> fileNames = new ArrayList<>();
for(int count=0; count < fields.length; count++) {
            Log.i("Raw Asset: ", fields[count].getName());
fileNames.add(fields[count].getName());
}
        return fileNames;
}
}

 class Mp3Filter implements FilenameFilter{
	public boolean accept(File dir, String name){
		return (name.endsWith(".mp3"));
	}
}

public class ringtone extends ListActivity  {
	
	public static final String SD_PATH = new String ("data/data/ir.rojaco.xxx.xxx/raw");
	private List<String> fileNames = new ArrayList<String>();
    java.lang.reflect.Field[] fields=R.raw.class.getFields();

 //   private List<String> songs = new ArrayList<String>();
	private MediaPlayer mp = new MediaPlayer();
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(layout.ringtone);

       // updatePlayList();
        
        getNameOfAllFileInRawFolder();
        
        ImageButton stopPlay = (ImageButton) findViewById(id.stopbtn);
 
        stopPlay.setOnClickListener(new OnClickListener() {
 
			public void onClick(View arg0) {
				mp.stop();
			}
		});
 
    }
 

 
    @Override
    protected void onListItemClick(ListView list, View view, int position, long id)
    {
    	try{
    		mp.reset();
    		mp.setDataSource(fields + fileNames.get(position));
    		mp.prepare();
    		mp.start();
    	} catch (IOException e){
    		Log.v(getString(string.app_name), e.getMessage());
    	}
    }
 /*
	private void updatePlayList() {
		
	
		File home = new File(SD_PATH);
		if(home.listFiles(new Mp3Filter()).length>0){
			for(File file: home.listFiles(new Mp3Filter())){
				fileNames.add(file.getName());
			}
 
			ArrayAdapter<String> songList = new ArrayAdapter<String>(this, layout.song_item, fileNames);
			setListAdapter(songList);
		}
    }
	
*/	
	public void getNameOfAllFileInRawFolder(){

			for(int count=0; count < fields.length; count++) {
			            Log.i("Raw Asset: ", fields[count].getName());
			            fileNames.add(fields[count].getName());
			}
			ArrayAdapter<String> songList = new ArrayAdapter<String>(this, layout.song_item, fileNames);
			
			setListAdapter(songList);
			
	}
	
	

        
}

من تست کردم اوکی بود

public class MyListActivity extends ListActivity {
    @Override
public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
setContentView(R.layout.list_activity);
getNameOfAllFileInRawFolder();
}
    public void getNameOfAllFileInRawFolder(){
        List<String> fileNames = new ArrayList<String>();
java.lang.reflect.Field[] fields=R.raw.class.getFields();
for(int count=0; count < fields.length; count++) {
            Log.i("Raw Asset: ", fields[count].getName());
fileNames.add(fields[count].getName());
}
        ArrayAdapter<String> songList = 
           new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, fileNames);
setListAdapter(songList);
}
}

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">

    <ListView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@android:id/list"
android:background="#aaaaaa" />

</LinearLayout>

الان ترک های داخل پوشه raw رو نشون میده اما وقتی کد کلیک روی لیست ویو رو اجرا میکنه برنامه فورس کلوز میده : 

کد مربوط به کلیک روی لیست ویو :

 protected void onListItemClick(ListView list, View view, int position, long id)
    {
    	try{
    		mp.reset();
    		mp.setDataSource(SD_PATH + songs.get(position));
    		mp.prepare();
    		mp.start();
    	} catch (IOException e){
    		Log.v(getString(R.string.app_name), e.getMessage());
    	}
    }

خطا هم روی دستور  :

    		mp.setDataSource(SD_PATH + songs.get(position));

دوباره دسترسی raw میخواد!