Check out example codes for "send variable intent". It will help you in understanding the concepts better.

Code Example 1

Intent intent = new Intent(getBaseContext(), SignoutActivity.class);
intent.putExtra("EXTRA_SESSION_ID", sessionId);
startActivity(intent);

Code Example 2

String sessionId = getIntent().getStringExtra("EXTRA_SESSION_ID");

Learn ReactJs, React Native from akashmittal.com