Estoy tratando de hacer un programa que pueda unir 2 archivos MP3 y guardarlos en la tarjeta SD de Android. Tengo un código Java que funciona, pero cuando intento convertirlo a Android, da un error.

En Java el código se escribe a continuación. Está funcionando perfecto.

import java.io.*;
public class TuneDoorJava {

    public static void main(String[] args) throws FileNotFoundException, IOException {
        FileInputStream fistream1 = new FileInputStream("F:\\aa.mp3");  // first source file
        FileInputStream fistream2 = new FileInputStream("F:\\bb.mp3");//second source file
        SequenceInputStream sistream = new SequenceInputStream(fistream1, fistream2);
        FileOutputStream fostream = new FileOutputStream("F:\\final.mp3");//destinationfile

        int temp;

        while( ( temp = sistream.read() ) != -1)
        {
            // System.out.print( (char) temp ); // to print at DOS prompt
            fostream.write(temp);   // to write to file
        }
        fostream.close();
        sistream.close();
        fistream1.close();
        fistream2.close();
    }
    }

En Android, lo que estoy tratando de hacer es:

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

      //  FileOutputStream fostream=null;
        FileInputStream fist=(FileInputStream)getResources().openRawResource(R.raw.t);
        FileInputStream fist2=(FileInputStream)getResources().openRawResource(R.raw.v);

        File sdCard = Environment.getExternalStorageDirectory();
        File dir = new File (sdCard.getAbsolutePath() + "/dir1");
        dir.mkdirs();
        File file = new File(dir, "filename");

       //FileInputStream fistream1 = new FileInputStream();  // first source file
        //FileInputStream fistream2 = new FileInputStream("F:\\bb.mp3");//second source file
        SequenceInputStream sistream = new SequenceInputStream(fist, fist2);

        FileOutputStream fostream = new FileOutputStream(file);

        int temp;
        while( ( temp = sistream.read() ) != -1)
        {
            // System.out.print( (char) temp ); // to print at DOS prompt
            fostream.write(temp);   // to write to file
        }
        fostream.close();
        sistream.close();
        fistream1.close();
        fistream2.close();
    }
}