Android Random string from file after button click

I have some problem with Random. I need choose one line from txt file and pass it into textview after button click (each time a different line). My code do this only one during the first click, but i want to for each button click next line is show. (sorry for my bad English) -_-

public class MainActivity extends Activity  {

long seed = System.nanoTime();
String newString1;


 /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);


      valueA();
      Button buttonGenerate = (Button)findViewById(R.id.button1);
      final TextView textGenerateNumber = (TextView)findViewById(R.id.textView1);

      buttonGenerate.setOnClickListener(new OnClickListener(){

  @Override
  public void onClick(View v) {
   // TODO Auto-generated method stub
      valueA();
      textGenerateNumber.setText(newString1);
  }});
  }



    public void valueA (){

            Scanner s = new Scanner(getResources().openRawResource(R.raw.question));
            ArrayList<String> list = new ArrayList<String>();

               try {
                   while (s.hasNextLine() ) {
                       list.add(s.nextLine());   
                   }
               } finally {
                   s.close();    
               }  

               Random r = new Random(seed);

               String a = list.get(r.nextInt(list.size()));

               newString1 = a.substring(2);

           }

}