Why isn’t the menu showing?

Question

I’m taking an online course and the menu part is not working in my Android Studio. First, I deleted the Contents who came, left only what is Activity in the Layout. About the code: The App starts in a list, I click on the "+" button and go to a form, in the form should appear in the menu the "Done" icon and so back to the list. It may be because I am using Activity and not content that is not showing the menu?

I’ll send you the code Androidmanifest.xml, Formularioactivity.java, Listaalunosactivity.java, activity_formulario.xml, activity_list_students.xml and menu_formulario.xml and can you tell me what I can change? In the emulator, nothing from the menu simply appears.

Androidmanifest.xml:

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="ygorfraga.agenda">

<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/AppTheme">
    <activity
        android:name=".ListaAlunosActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".FormularioActivity"
        android:label="@string/title_activity_formulario"
        android:theme="@style/AppTheme.NoActionBar"></activity>
</application>

Formularioactivity.java:

public class FormularioActivity extends AppCompatActivity {

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

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.menu_formulario, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()){
        case R.id.menu_formulario_ok:
            Toast.makeText(FormularioActivity.this, "Aluno Salvo!", Toast.LENGTH_SHORT).show();
            finish();
            break;
    }
    return super.onOptionsItemSelected(item);
 }

}

Listaalunosactivity.java:

public class ListaAlunosActivity extends AppCompatActivity {

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

    String[] alunos = {"Daniel", "Ronaldo", "Jefferson", "Felipe"};

    ListView listaAlunos = (ListView) findViewById(R.id.lista_alunos);
    ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, alunos);
    listaAlunos.setAdapter(adapter);

    Button novoAluno = (Button) findViewById(R.id.novo_aluno);
    novoAluno.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intentVaiProFormulario = new Intent(ListaAlunosActivity.this, FormularioActivity.class);
            startActivity(intentVaiProFormulario);
        }
    });
}
}

activity_formulario.xml:

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Nome"
        android:id="@+id/formulario_nome"/>

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Endereço"
        android:id="@+id/formulario_endereco"/>

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Telefone"
        android:id="@+id/formulario_telefone"/>

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="Site"
        android:id="@+id/formulario_site"/>

    <RatingBar
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:max="10"
        android:numStars="5"
        android:id="@+id/formulario_nota"/>

</LinearLayout>

lista_alunos_activity.xml:

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/activity_lista_alunos"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<ListView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/lista_alunos" />

<Button
    android:id="@+id/novo_aluno"
    android:layout_width="56dp"
    android:layout_height="56dp"
    android:text="+"
    android:textColor="#fff"
    android:textSize="40sp"
    android:elevation="6dp"
    android:layout_alignParentBottom="true"
    android:layout_alignParentRight="true"
    android:layout_marginBottom="16dp"
    android:layout_marginRight="16dp"
    android:background="@drawable/fundo"
    android:stateListAnimator="@null"/>

menu_formulario.xml:

<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">

<item
    android:id="@+id/menu_formulario_ok"
    android:title="Ok"
    android:icon="@drawable/ic_confirmar"
    app:showAsAction="always"/>

Answer 1

In your Manifest, make this change.

<activity
    android:name=".FormularioActivity"
    android:label="@string/title_activity_formulario"
    android:theme="@style/AppTheme"></activity>