Retrieving a list of Contacts and showing them like WhatsApp (ListView-Fragment-ViewPager)

Here is the official android developer example regarding Retrieving a List of Contacts, read and understand well. Though I am not going to use all the function. My aim is to display a list of contact from phone, to a swipe-able screen fragment-like favorites in WhatsApp.

Notes:
1.You can always use custom id for ListView in xml other than @android:id/list , say. @+id/mylist.
    Same goes for @android:id/text1.
2. Loader Manager is used to load data asynchronously in an activity or fragment.

 Here is the OnCreate() of my MainActivity.java


        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
      try {
          tabLayout.addTab(tabLayout.newTab().setText("helloo"));
          tabLayout.addTab(tabLayout.newTab().setText("Tab 2"));
          tabLayout.addTab(tabLayout.newTab().setText("Tab 3"));
          tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
          }catch (Exception e)
                 {e.printStackTrace();}

        final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
        final PagerAdapter adapter = new PagerAdapter
                (getSupportFragmentManager(), tabLayout.getTabCount());
        viewPager.setAdapter(adapter);
        viewPager.addOnPageChangeListener(new
                             TabLayout.TabLayoutOnPageChangeListener(tabLayout));
        tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                viewPager.setCurrentItem(tab.getPosition());
             }
I used Tabbed + swipe-able page...
tabLayout.addTab literally creates a new Tab with title written inside the setText().
A ViewPager is placed inside the xml code with id pager, and is initialized here, for navigation across the screen.
Also an object of PagerAdapter.class (

Here is activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main_layout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.sunshelltechnologies.asimpletabact.MainActivity">

    <android.support.design.widget.TabLayout
        android:id="@+id/tab_layout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="?attr/colorPrimary"
        android:elevation="6dp"
        android:minHeight="?attr/actionBarSize"
        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"/>

    <android.support.v4.view.ViewPager
        android:id="@+id/pager"
        android:layout_width="match_parent"
        android:layout_height="fill_parent"
        android:layout_below="@id/tab_layout"/>
</RelativeLayout>


Another class PagerAdapter.java is created

public class PagerAdapter extends FragmentStatePagerAdapter {
    int mNumOfTabs;
    public PagerAdapter(FragmentManager fm, int NumOfTabs) {
                       super(fm);
          this.mNumOfTabs = NumOfTabs;
    }
    @Override
    public Fragment getItem(int position) {

        switch (position) {
            case 0:
                TabFragment1 tab1 = new TabFragment1();
                return tab1;
            case 1:
                TabFragment2 tab2 = new TabFragment2();
                return tab2;
            case 2:
                TabFragment3 tab3 = new TabFragment3();
                return tab3;
            default:
                return null;
        }
    }
    @Override
    public int getCount() {
        return mNumOfTabs;
    }
}
For each page,view, I created each java file naming them TabFragment1,2,3 as you can see.
The basic code inside these are:

public class TabFragment1 extends Fragment {
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.tab_fragment_1, container, false);
    } }


Although, for retrieving contact on the third screen, I added some codes in TabFragment3.java.

public class TabFragment3  extends Fragment {
    // Cursor Adapter for storing contacts data
    SimpleCursorAdapter adapter;
    // List View Widget
    ListView lvContacts;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        return inflater.inflate(R.layout.tab_fragment_3, container, false);
    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
      // OnActivityCreated work after onCreateView
        lvContacts = (ListView) getView().findViewById(R.id.fragment_3);
      // Initialize Content Resolver object to work with content Provider
        ContentResolver cr=getActivity().getContentResolver();
        Cursor c = cr.query(ContactsContract.Contacts.CONTENT_URI,
                new String[] { ContactsContract.Contacts._ID,
                        ContactsContract.Contacts.DISPLAY_NAME }, 
                        null, null,  null);

        Context context = getActivity();
        adapter = new SimpleCursorAdapter(context,
                           R.layout.single_item, //the layout containing TextView
                               c,   //the cursor
            new String[] { ContactsContract.Contacts.DISPLAY_NAME }, //content
                new int[] { R.id.myTextView },  //to where?
                0);       //flag 0=no requery loader
       
        lvContacts.setAdapter(adapter);
       }
}
Note that there are 3 xml for each view (tab_fragment_1.xml, tab_fragment_2.xml contain nothing inside).
tab_fragment_3.xml

<?xml version="1.0" encoding="utf-8"?>
<ListView android:id="@+id/fragment_3" xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
  />
single_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
    android:layout_height="match_parent"
    >
<TextView
        android:id="@+id/myTextView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" />
</LinearLayout>