Cách di chuyển giữa các màn hình - activity và lấy giá tri trong màn hình đưa qua màn hình mới

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends AppCompatActivity {
    Button next;
    EditText hoTen;
    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        next = (Button) findViewById(R.id.buttonNext);
        hoTen = (EditText) findViewById(R.id.editTextHoTen);
        next.setOnClickListener(new View.OnClickListener() {
            @Override            public void onClick(View v) {
                Intent diChuyen = new Intent(MainActivity.this,Main2Activity.class);
                diChuyen.putExtra("HoTen",hoTen.getText().toString());// string, Bundle de su dung man hinh 2                // nho la khong phai startActivities                startActivity(diChuyen);
            }
        });

    }

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class Main2Activity extends AppCompatActivity {
    Button pre;
    TextView hoTenLayDuoc;
    @Override    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        pre = (Button) findViewById(R.id.buttonPre);
        hoTenLayDuoc = (TextView) findViewById(R.id.textViewHoTenLayDuoc);
        Bundle bd = getIntent().getExtras();
        if(bd!=null)
        hoTenLayDuoc.setText(bd.getString("HoTen"));
        pre.setOnClickListener(new View.OnClickListener() {
            @Override            public void onClick(View v) {

                Intent diChuyen = new Intent(Main2Activity.this,MainActivity.class);
                startActivity(diChuyen);
            }
        });
    }
}