Toggle button to open drawer

I'm trying to put a tab in my app , created from scratch with the template of navigation drawer with android studio, but the button toggle in, Tab.class , does not work to open the drawer , as I get it?

My Tab.class

public class Tab extends AppCompatActivity {

private SectionsPagerAdapter mSectionsPagerAdapter;


private ViewPager mViewPager;

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

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());


    mViewPager = (ViewPager) findViewById(R.id.container);
    mViewPager.setAdapter(mSectionsPagerAdapter);

    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
    tabLayout.setupWithViewPager(mViewPager);
    Toolbar tb = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(tb);
    ActionBar ab = getSupportActionBar();
    ab.setHomeAsUpIndicator(drawer_toggle);
    ab.setDisplayHomeAsUpEnabled(true);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {

    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {

    int id = item.getItemId();

    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

public static class PlaceholderFragment extends Fragment {

    private static final String ARG_SECTION_NUMBER = "section_number";

    public PlaceholderFragment() {
    }

    public static PlaceholderFragment newInstance(int sectionNumber) {
        PlaceholderFragment fragment = new PlaceholderFragment();
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_tab, container, false);
        TextView textView = (TextView) rootView.findViewById(R.id.section_label);
        textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
        return rootView;
    }
}

public class SectionsPagerAdapter extends FragmentPagerAdapter {

    public SectionsPagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {
        return PlaceholderFragment.newInstance(position + 1);
    }

    @Override
    public int getCount() {
        return 3;
    }

    @Override
    public CharSequence getPageTitle(int position) {
        switch (position) {
            case 0:
                return "SECTION 1";
            case 1:
                return "SECTION 2";
            case 2:
                return "SECTION 3";
        }
        return null;
     }
   }
  }

activity_tab.xml

<?xml version="1.0" encoding="utf-8"?>

<android.support.design.widget.AppBarLayout
    android:id="@+id/appbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:paddingTop="@dimen/appbar_padding_top"
    android:theme="@style/AppTheme.AppBarOverlay">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        android:background="?attr/colorPrimary"
        app:layout_scrollFlags="scroll|enterAlways"
        app:popupTheme="@style/AppTheme.PopupOverlay">

    </android.support.v7.widget.Toolbar>

    <android.support.design.widget.TabLayout
        android:id="@+id/tabs"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />

</android.support.design.widget.AppBarLayout>

<android.support.v4.view.ViewPager
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    app:layout_behavior="@string/appbar_scrolling_view_behavior" />

<android.support.design.widget.FloatingActionButton
    android:id="@+id/fab"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="end|bottom"
    android:layout_margin="@dimen/fab_margin"
    app:srcCompat="@android:drawable/ic_dialog_email" />

menu_drawer.xml

<?xml version="1.0" encoding="utf-8"?>

    <item
        android:id="@+id/MENU_JUVENIL"
        android:title="JUVENIL" >

            <menu>

                    <item
                        android:id="@+id/item_actual_juvenil"
                        android:icon="@drawable/categorias"
                        android:title="Semana actual" />

                    <item
                        android:id="@+id/item_calendario_juvenil"
                        android:checked="true"
                        android:icon="@drawable/inicio"
                        android:title="Calendario" />
                    <item
                        android:id="@+id/item_jornadas_juvenil"
                        android:icon="@drawable/cuenta"
                        android:title="@string/item_jornadas_juvenil" />

            </menu>
    </item>


    <item
        android:id="@+id/MENU_CADETES"
        android:title="CADETES" >

    <menu>

    <item
        android:id="@+id/item_categorias"
        android:icon="@drawable/categorias"
        android:title="@string/item_categorias" />

            <item
                android:id="@+id/item_configuracion"
                android:icon="@drawable/configuracion"
                android:title="@string/item_configuracion" />

    </menu>
    </item>

Thanks