Is there a way in which I can create a single NavigationView (with its elements) and call other custom activites while maintaining the same NavigationView for all of them?
I did as @johnrao07 said and created an Activity that will work as a BaseActivity for all my activities. It looks like this:
public class BaseActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
HealthFileSQLiteOpenHelper healthFileHelper;
SQLiteDatabase db;
DrawerLayout drawerLayout;
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    getSupportActionBar().setDisplayShowTitleEnabled(false);
    drawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
    ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
            this, drawerLayout, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
    drawerLayout.setDrawerListener(toggle);
    toggle.syncState();
    NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
    navigationView.setNavigationItemSelectedListener(this);
}
@Override
public void onBackPressed() {
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    if (drawer.isDrawerOpen(GravityCompat.START)) {
        drawer.closeDrawer(GravityCompat.START);
    } else {
        super.onBackPressed();
    }
}
@Override
public boolean onNavigationItemSelected(MenuItem menuItem) {
    // Handle navigation view item clicks here.
    int id = menuItem.getItemId();
    if (id == R.id.nav_home) {
        // Handle the camera action
        finish();
    } else if (id == R.id.nav_log_out) {
        finish();
    }
    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}
}
Then I have a custom Activity that I want it to extend from BaseActivity: 
public class ProfilesActivity extends BaseActivity  {
 @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // TROUBLE HERE
    setContentView(R.layout.profiles_content);
}
I want this Activity to have its own content, and I want the NavigationView to be showed at any Activity that extends from BaseActivity... 
With no luck...
This is my xml:
main.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
    layout="@layout/app_bar_main"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
<android.support.design.widget.NavigationView
    android:id="@+id/nav_view"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:fitsSystemWindows="true"
    android:background="@android:color/white"
    app:headerLayout="@layout/nav_header_main"
    app:menu="@menu/activity_main_drawer" />
</android.support.v4.widget.DrawerLayout>
app_bar_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.testnavigation2.MainActivity">
<android.support.design.widget.AppBarLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:elevation="0dp"
    android:theme="@style/AppTheme.AppBarOverlay">
    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="?attr/actionBarSize"
        app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<!-- <include layout="@layout/profiles_content" /> -->
<FrameLayout
    android:id="@+id/content_frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >
    <!-- Put what you want as your normal screen in here, you can also choose for a linear layout or any other layout, whatever you prefer -->
</FrameLayout>
</android.support.design.widget.CoordinatorLayout>
But I still can't see the NavigationView at each Activity (with this method I lost it completely from my screen).
Any idea on what I'm doing wrong?
 
     
    