Need help passing data between two activities

Question

I have two activities. Mainactivity.java and door1.java. On mainactivity.java I have a textview named plaintxt that I need to pass to textveiw named door1textview on door1.java. I have been trying for a while but no luck.

Answer 1

use below code in Mainactivity whether you need to pass data

Intent intent = new Intent(getBaseContext(), door1.class);
intent.putExtra("KEY", value);
startActivity(intent);

and you will be able to receive data in door1 activity like below

String value= getIntent().getStringExtra("KEY");

you can see more from here

Answer 2

use intent to pass data between two activity like this MainActivity

String value=user_name.getText().toString().trim();

on Button Click

Intent theIntent = new Intent(this, SecondActivity.class);
theIntent.putExtra("name", value);
startActivity(theIntent);

SecondActivity

 Intent i= getIntent();
i.getStringExtra("name");

another way to get data

Bundle extras = getIntent().getExtras(); 
String userName;

if (extras != null) {
userName = extras.getString("name");
// and get whatever type user account id is
 }