This gist is for activating share button in your android application.

Android - Activate "Share" button in your App

// add the following code to your button:

  Intent sharingIntent = new Intent(android.content.Intent.ACTION_SEND);
  sharingIntent.setType("text/plain");
  String shareBody = "Here is the share content body";
  sharingIntent.putExtra(android.content.Intent.EXTRA_SUBJECT, "Subject Here");
  sharingIntent.putExtra(android.content.Intent.EXTRA_TEXT, shareBody);
  startActivity(Intent.createChooser(sharingIntent, "Share via"));