LoaderManager
LoaderManager.LoaderCallbacks
Loader
AsyncTaskLoader
CursorLoader

public class TestLoadersActivity
extends      MonitoredListActivity //very simple class to log activity callbacks
implements   LoaderManager.LoaderCallbacks<Cursor> //Loader Manager callbacks
             ,OnQueryTextListener //Search text callback to filter contacts
{
   private static final String tag = "TestLoadersActivity";

   //Adapter for displaying the list's data
   //Initialized to null cursor in onCreate and set on the list
   //Use it in later callbacks to swap cursor
   //This is reinitialized to null cursor when rotation occurs
    SimpleCursorAdapter mAdapter;

    //Search filter working with OnQueryTextListener
    String mCurFilter;

    //Contacts columns that we will retrieve
    static final String[] PROJECTION = new String[] {ContactsContract.Data._ID,
            ContactsContract.Data.DISPLAY_NAME};

    //select criteria for the contacts URI
    static final String SELECTION = "((" +
            ContactsContract.Data.DISPLAY_NAME + " NOTNULL) AND (" +
            ContactsContract.Data.DISPLAY_NAME + " != '' ))";

    public TestLoadersActivity()  {
       super(tag);
    }
    @Override
    protected void onCreate(Bundle savedInstanceState)  {
       super.onCreate(savedInstanceState);
       this.setContentView(R.layout.test_loaders_activity_layout);

       //Initialize the adapter
       this.mAdapter = createEmptyAdapter();
       this.setListAdapter(mAdapter);

       //Hide the listview and show the progress bar
       this.showProgressbar();

       //Initialize a loader for an id of 0
       getLoaderManager().initLoader(0, null, this);
    }
    //Create a simple list adapter with a null cursor
    //The good cursor will come later in the loader callback
    private SimpleCursorAdapter createEmptyAdapter() {
       // For the cursor adapter, specify which columns go into which views
        String[] fromColumns = {ContactsContract.Data.DISPLAY_NAME};
        int[] toViews = {android.R.id.text1}; // The TextView in simple_list_item_1
        //Return the cursor
       return new SimpleCursorAdapter(this,
             android.R.layout.simple_list_item_1,
             null, //cursor
             fromColumns,
             toViews);
    }
   //This is a LoaderManager callback. Return a properly constructed CursorLoader
   //This gets called only if the loader does not previously exist.
   //This means this method will not be called on rotation because
   //a previous loader with this ID is already available and initialized.
   //This also gets called when the loader is "restarted" by calling
   //LoaderManager.restartLoader()
   @Override
   public Loader<Cursor> onCreateLoader(int id, Bundle args) {
      Log.d(tag,"onCreateLoader for loader id:" + id);
      Uri baseUri;
      if (mCurFilter != null) {
          baseUri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_FILTER_URI,
                 Uri.encode(mCurFilter));
      } else {
          baseUri = Contacts.CONTENT_URI;
      }
      String[] selectionArgs = null;
      String sortOrder = null;
      return new CursorLoader(this, baseUri,
            PROJECTION, SELECTION, selectionArgs, sortOrder);
   }
   //This is a LoaderManager callback. Use the data here.
   //This gets called when he loader finishes. Called on the main thread.
   //Can be called multiple times as the data changes underneath.
   //Also gets called after rotation with out requerying the cursor.
   @Override
   public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
       Log.d(tag,"onLoadFinished for loader id:" + loader.getId());
       Log.d(tag,"Number of contacts found:" + cursor.getCount());
        this.hideProgressbar();
        this.mAdapter.swapCursor(cursor);
   }
   //This is a LoaderManager callback. Remove any references to this data.
   //This gets called when the loader is destroyed like when activity is done.
   //FYI - this does NOT get called because of loader "restart"
   //This can be seen as a "destructor" for the loader.
   @Override
   public void onLoaderReset(Loader<Cursor> loader) {
      Log.d(tag,"onLoaderReset for loader id:" + loader.getId());
      this.showProgressbar();
      this.mAdapter.swapCursor(null);
   }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Place an action bar item for searching.
        MenuItem item = menu.add("Search");
        item.setIcon(android.R.drawable.ic_menu_search);
        item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
        SearchView sv = new SearchView(this);
        sv.setOnQueryTextListener(this);
        item.setActionView(sv);
        return true;
    }
    //This is a Searchview callback. Restart the loader.
    //This gets called when user enters new search text.
    //Call LoaderManager.restartLoader to trigger the onCreateLoader
    @Override
    public boolean onQueryTextChange(String newText) {
        // Called when the action bar search text has changed.  Update
        // the search filter, and restart the loader to do a new query
        // with this filter.
        mCurFilter = !TextUtils.isEmpty(newText) ? newText : null;
        Log.d(tag,"Restarting the loader");
        getLoaderManager().restartLoader(0, null, this);
        return true;
    }
    @Override
    public boolean onQueryTextSubmit(String query) {
        return true;
    }
    private void showProgressbar() {
       //show progress bar
       View pbar = this.getProgressbar();
       pbar.setVisibility(View.VISIBLE);
       //hide listview
       this.getListView().setVisibility(View.GONE);
       findViewById(android.R.id.empty).setVisibility(View.GONE);
    }
    private void hideProgressbar()  {
       //show progress bar
       View pbar = this.getProgressbar();
       pbar.setVisibility(View.GONE);
       //hide listview
       this.getListView().setVisibility(View.VISIBLE);
    }
    private View getProgressbar()  {
       return findViewById(R.id.tla_pbar);
    }
}//eof-class

<?xml version="1.0" encoding="utf-8"?>
<!--
*********************************************
* /res/layout/test_loaders_activity_layout.xml
* corresponding activity: TestLoadersActicity.java
* prefix: tla_ (Used for prefixing unique identifiers)
*
* Use:
*    Demonstrate loading a cursor using loaders
* Structure:
*    Header message: text view (tla_header)
*    ListView Heading, ListView (fixed)
*    ProgressBar (To show when data is being fetched)
*    Empty View (To show when the list is empty): ProgressBar
*    Footer: text view (tla_footer)
************************************************
-->
<LinearLayout xmlns:android="[http://schemas.android.com/apk/res/android](http://schemas.android.com/apk/res/android)"
    android:orientation="vertical"
    android:layout_width="match_parent"  android:layout_height="match_parent"
    android:paddingLeft="2dp"  android:paddingRight="2dp">
    <!--  Header and Main documentation text -->
    <TextView android:id="@+id/tla_header"
        android:layout_width="match_parent"  android:layout_height="wrap_content"
        android:background="@drawable/box2"
        android:layout_marginTop="4dp" android:padding="8dp"
        android:text="@string/tla_header"/>
    <!--  Heading for the list view -->
    <TextView android:id="@+id/tla_listview_heading"
        android:layout_width="match_parent"    android:layout_height="wrap_content"
        android:background="@color/gray"
        android:layout_marginTop="4dp"  android:padding="8dp"
        android:textColor="@color/black" style="@android:style/TextAppearance.Medium"
        android:text="List of Contacts"/>
    <!--  ListView used by the ListActivity. Uses a standard id needed by a list view -->
    <!--  Fix the height of the listview in a production setting -->
    <ListView android:id="@android:id/list"
        android:layout_width="match_parent"  android:layout_height="wrap_content"
        android:background="@drawable/box2"
        android:layout_marginTop="4dp" android:layout_marginBottom="4dp"
        android:drawSelectorOnTop="false"/>
    <!--  ProgressBar: To show and hide the progress bar as loaders load data -->
    <ProgressBar android:id="@+id/tla_pbar"
        android:layout_width="match_parent" android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:indeterminate="true"/>
     <!--  Empty List: Uses a standard id needed by a list view -->
     <TextView android:id="@android:id/empty"
        android:layout_width="match_parent" android:layout_height="wrap_content"
        android:visibility="gone"
        android:layout_marginTop="4dp"  android:layout_marginBottom="4dp"
        android:padding="8dp"
        android:text="No Contacts to Match the Criteria"/>
     <!--  Footer: Additional documentation text and the footer-->
     <TextView android:id="@+id/tla_footer"
        android:layout_width="match_parent"  android:layout_height="wrap_content"
        android:background="@drawable/box2"  android:padding="8dp"
        android:text="@string/tla_footer"/>
</LinearLayout>

int loaderid = 0; Bundle argBundle = null;
LoaderCallbacks<Cursor> loaderCallbacks = this; //this activity itself
getLoaderManager().initLoader(loaderid, argBundle, loaderCallbacks);

Application.onCreate()
Activity.onCreate()
  LoaderManager.LoaderCallbacks.onCreateLoader()
  Activity.onStart()
  Activity.onResume()
  LoaderManager.LoaderCallbacks.onLoadFinished()

RestartLoader //log message from onQueryTextChange
LoaderManager.LoaderCallbacks.onCreateLoader()
LoaderManager.LoaderCallbacks.onLoadFinished()
//Notice, no call to onLoaderReset()

Application:config changed
Activity: onCreate
  Activity.onStart
  [No call to the onCreateLoader]
  LoaderManager.LoaderCallbacks.onLoadFinished
  [optionally if searchview has text in it]
    SearchView.onQueryChangeText
    RestartLoader //just a log message
    LoaderManager.LoaderCallbacks.onCreateLoader
    LoaderManager.LoaderCallbacks.onLoadFinished

ActivityonStop()
Activity.onDestroy()
LoaderManager.LoaderCallbacks.onLoaderReset() //Notice this method is called