código activity formulário

package alura.com.br.ui.activity;

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.EditText;
import android.widget.Toast; 

import alura.com.br.DAO.AlunoDAO;
import alura.com.br.R;
import alura.com.br.model.Aluno;

public class FormularioAlunoActivity extends AppCompatActivity {


    public static final String TITLE = "Novo Aluno";
    private EditText campoNome;
    private EditText campoTelefone;
    private EditText campoEmail;
    private final AlunoDAO DAO = new AlunoDAO();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_formulario_aluno);
        setTitle(TITLE);
        inicializacaoDosCampos();
        configuraBotaoSalvar();
    }

    private void configuraBotaoSalvar() {
        Button botaoSalvar = findViewById(R.id.activity_formulario_aluno_salvar);
        botaoSalvar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(FormularioAlunoActivity.this, "Salvo", Toast.LENGTH_SHORT).show();
                Aluno alunoCriado = criaAluno(campoNome, campoTelefone, campoEmail);
                salvar(alunoCriado);
                startActivity(new Intent(FormularioAlunoActivity.this, ListaAlunosActivity.class));
            }
        });
    }

    private void inicializacaoDosCampos() {
        campoNome = findViewById(R.id.activity_formulario_aluno_nome);
        campoTelefone = findViewById(R.id.activity_formulario_aluno_telefone);
        campoEmail = findViewById(R.id.activity_formulario_aluno_email);

    }

    private void salvar(Aluno aluno) {
        DAO.salva(aluno);

    }

    private Aluno criaAluno(EditText campoNome, EditText campoTelefone, EditText campoEmail) {
        String nome = this.campoNome.getText().toString();
        String telefone = this.campoTelefone.getText().toString();
        String email = this.campoEmail.getText().toString();
        Aluno alunoCriado = new Aluno(nome, telefone, email);
        return alunoCriado;
    }
}

código AndroidManifast.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="alura.com.br">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Agenda">

        <activity
            android:name=".ui.activity.ListaAlunosActivity"
            android:exported="true">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name=".ui.activity.FormularioAlunoActivity"
            android:exported="true"/>
    </application>

</manifest>