Query Contacts database using Loader, with search function.

Example of query Contacts database using Loader, with search menu item.

package com.example.androidsearchcontact;

import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract.Contacts;
import android.app.ListActivity;
import android.app.LoaderManager;
import android.app.LoaderManager.LoaderCallbacks;
import android.content.CursorLoader;
import android.content.Loader;
import android.database.Cursor;
import android.text.TextUtils;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.ListView;
import android.widget.SearchView;
import android.widget.SearchView.OnQueryTextListener;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;

public class MainActivity extends ListActivity implements 
 OnQueryTextListener, LoaderCallbacks<Cursor>{
 
 SimpleCursorAdapter simpleCursorAdapter;
 String cursorFilter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.activity_main);
        
        String[] from = new String[]{
          Contacts.DISPLAY_NAME, 
          Contacts.CONTACT_STATUS};
        
        int[] to = new int[]{
          android.R.id.text1, 
          android.R.id.text2};
        
        simpleCursorAdapter = new SimpleCursorAdapter(this,
                android.R.layout.simple_list_item_2, 
                null,
                from,
                to, 
                0);
        
        setListAdapter(simpleCursorAdapter);
        
        LoaderManager loaderManager = getLoaderManager();
        loaderManager.initLoader(0, null, this);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        //getMenuInflater().inflate(R.menu.activity_main, menu);
     
     MenuItem item = menu.add("Search");
        item.setIcon(android.R.drawable.ic_menu_search);
        item.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM);
        SearchView searchView = new SearchView(MainActivity.this);
        searchView.setOnQueryTextListener(this);
        item.setActionView(searchView);
     
        return true;
    }

 @Override
 public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
  Uri baseUri;
        if (cursorFilter != null) {
            baseUri = Uri.withAppendedPath(Contacts.CONTENT_FILTER_URI,
                    Uri.encode(cursorFilter));
        } else {
            baseUri = Contacts.CONTENT_URI;
        }

        String select = "((" + Contacts.DISPLAY_NAME + " NOTNULL) AND ("
                + Contacts.HAS_PHONE_NUMBER + "=1) AND ("
                + Contacts.DISPLAY_NAME + " != '' ))";
        
        String[] projection = new String[] {
            Contacts._ID,
            Contacts.DISPLAY_NAME,
            Contacts.CONTACT_STATUS,
            Contacts.CONTACT_PRESENCE,
            Contacts.PHOTO_ID,
            Contacts.LOOKUP_KEY,
        };
        
        CursorLoader cursorLoader = new CursorLoader(
          MainActivity.this, 
          baseUri,
                projection, 
                select, 
                null,
                Contacts.DISPLAY_NAME);
        
        return cursorLoader;
 }

 @Override
 public void onLoadFinished(Loader<Cursor> arg0, Cursor arg1) {
  simpleCursorAdapter.swapCursor(arg1);
 }

 @Override
 public void onLoaderReset(Loader<Cursor> arg0) {
  simpleCursorAdapter.swapCursor(null);
 }

 @Override
 public boolean onQueryTextChange(String arg0) {
  cursorFilter = !TextUtils.isEmpty(arg0) ? arg0 : null;
        getLoaderManager().restartLoader(0, null, this);
        return true;
 }

 @Override
 public boolean onQueryTextSubmit(String arg0) {
  // TODO Auto-generated method stub
  return false;
 }

 @Override
 protected void onListItemClick(ListView l, View v, int position, long id) {
  
  Cursor cursor = (Cursor)l.getItemAtPosition(position);
  int item_ID = cursor.getInt(cursor.getColumnIndex(Contacts._ID));
  String item_DisplayName = cursor.getString(cursor.getColumnIndex(Contacts.DISPLAY_NAME));
  String item_LookUp = cursor.getString(cursor.getColumnIndex(Contacts.LOOKUP_KEY));
  
  String item = String.valueOf(item_ID) + ": " + item_DisplayName + "\n" 
    + "LOOKUP_KEY: " + item_LookUp;

  Toast.makeText(getApplicationContext(), 
    item, 
    Toast.LENGTH_LONG).show();
  
 }
    
}

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