Pass a String from one Activity to another Activity in Android

You need to pass it as an extra:

String easyPuzzle  = "630208010200050089109060030"+
                     "008006050000187000060500900"+
                     "09007010681002000502003097";

Intent i = new Intent(this, ToClass.class);
i.putExtra("epuzzle", easyPuzzle);
startActivity(i); 

Then extract it from your new activity like this:

Intent intent = getIntent();
String easyPuzzle = intent.getExtras().getString("epuzzle");

In activity1

    String easyPuzzle  = "630208010200050089109060030"+
                 "008006050000187000060500900"+
                 "09007010681002000502003097";

    Intent i = new Intent (this, activity2.class);

    i.putExtra("puzzle", easyPuzzle);
    startActivity(i);

In activity2

    Intent i = getIntent();
    String easyPuzzle = i.getStringExtra("puzzle");