EditText et_Nombre, et_Password;
private Cursor fila;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    et_Nombre = findViewById(R.id.usuario_ET);
    et_Password = findViewById(R.id.password_ET);


    bt_registrarse = findViewById(R.id.registrar_BT);
    bt_registrarse.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent registroClass = new Intent(MainActivity.this, Registro.class);
            MainActivity.this.startActivity(registroClass);
        }
    });


    bt_Ingresar = findViewById(R.id.login_BT);
    bt_Ingresar.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            BaseHelper user = new BaseHelper(MainActivity.this, "Demo", null, 1);
            SQLiteDatabase db = user.getWritableDatabase();

            String usuario = et_Nombre.getText().toString();
            String password = et_Password.getText().toString();

            fila = db.rawQuery("SELECT  NOMBRE, PASSWORD FROM PERSONAS WHERE NOMBRE='"+usuario+"' AND PASSWORD='"+password+"'", null);

            if(fila.moveToFirst()){
                String usua = fila.getString(1);
                String pass = fila.getString(2);

                if (usuario.equals(usua) && password.equals(pass)){
                    Intent intent = new Intent(MainActivity.this, twoMain.class);

                    startActivity(intent);
                    et_Nombre.setText("");
                    et_Password.setText("");
                }
            }
            else{
                Toast.makeText(MainActivity.this, "Error al ingresar datos", Toast.LENGTH_SHORT).show();
            }
        }
    });


}//end onCreate