Codice esercizio gestione suonerie

Mi salvo il codice sulla gestione delle suonerie...

public class MainActivity extends AppCompatActivity {

    Uri ringtoneUri;
    Button button;
    SharedPreferences SP;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        button=(Button)findViewById(R.id.button);
        SP=getApplicationContext().getSharedPreferences("settings",MODE_PRIVATE);




        button.setOnClickListener(new View.OnClickListener(){

            @Override
            public void onClick(View v) {
                String strSuoneria=SP.getString("suoneria","");
                if(TextUtils.isEmpty(strSuoneria)){
                    ringtoneUri=null;

                }
                else{
                    ringtoneUri=Uri.parse(strSuoneria);
                }

                System.out.println("Stringa pescata da SharedPreferences: "+strSuoneria);
                if(ringtoneUri!=null)System.out.println("ringtoneUri selezionata: "+ringtoneUri.toString());



                Intent intent=new Intent(RingtoneManager.ACTION_RINGTONE_PICKER);
                intent.putExtra(RingtoneManager.EXTRA_RINGTONE_TYPE,RingtoneManager.TYPE_NOTIFICATION);

                intent.putExtra(RingtoneManager.EXTRA_RINGTONE_EXISTING_URI,ringtoneUri);
                startActivityForResult(intent,0);
            }
        });


    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data){
        if(resultCode==RESULT_OK) {
            Uri uri = data.getParcelableExtra(RingtoneManager.EXTRA_RINGTONE_PICKED_URI);
            String s;
            if(uri==null){
                s="";
            }
            else{
                s=uri.toString();
            }
            System.out.println("Stringa memorizzata in SP: "+s);
            SharedPreferences.Editor editor = SP.edit();
            editor.putString("suoneria", s);
            editor.commit();
        }
    }
}

in modo da usare il programma per fare dell'altro.