Android How to - Projections in Contact Content Provider

• Back to ContentProvider  ↑

The second parameter of the managedQuery() method and third parameter for the CursorLoader class controls how many columns are returned by the query.

This parameter is known as the projection. Earlier, you specified null:

Example

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

<ListView
    android:id="@+id/list"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:stackFromBottom="false"
    android:transcriptMode="normal" />

<TextView
    android:id="@+id/contactName"
    android:textStyle="bold"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" />

<TextView
    android:id="@+id/contactID"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />

</LinearLayout>

Java code

package com.java2s.myapplication3.app;
/*  ww  w . ja va  2s .  co  m*/
import android.app.ListActivity;
import android.content.CursorLoader;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.widget.CursorAdapter;
import android.widget.SimpleCursorAdapter;

public class MainActivity extends ListActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Uri allContacts = Uri.parse("content://contacts/people");

        String[] projection = new String[]
                {ContactsContract.Contacts._ID,
                        ContactsContract.Contacts.DISPLAY_NAME,
                        ContactsContract.Contacts.HAS_PHONE_NUMBER};

        Cursor c;
        if (android.os.Build.VERSION.SDK_INT < 11) {
            //before Honeycomb
            c = managedQuery(allContacts, projection, null, null, null);
        } else {
            //Honeycomb and later
            CursorLoader cursorLoader = new CursorLoader(
                    this,
                    allContacts,
                    projection,
                    null,
                    null,
                    null);
            c = cursorLoader.loadInBackground();
        }


        String[] columns = new String[]{
                ContactsContract.Contacts.DISPLAY_NAME,
                ContactsContract.Contacts._ID};

        int[] views = new int[]{R.id.contactName, R.id.contactID};

        SimpleCursorAdapter adapter;

        if (android.os.Build.VERSION.SDK_INT < 11) {
            //before Honeycomb
            adapter = new SimpleCursorAdapter(
                    this, R.layout.activity_main, c, columns, views);
        } else {
            //Honeycomb and later
            adapter = new SimpleCursorAdapter(
                    this, R.layout.activity_main, c, columns, views,
                    CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
        }

        this.setListAdapter(adapter);
    }

    private void PrintContacts(Cursor c) {
        if (c.moveToFirst()) {
            do {
                String contactID = c.getString(c.getColumnIndex(
                        ContactsContract.Contacts._ID));
                String contactDisplayName =
                        c.getString(c.getColumnIndex(
                                ContactsContract.Contacts.DISPLAY_NAME));

            } while (c.moveToNext());
        }
    }

}

Add the following statements to the AndroidManifest.xml file:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
     package="com.java2s.Provider"
     android:versionCode="1"
     android:versionName="1.0" >

     <uses-sdk android:minSdkVersion="14" />
     <uses-permission android:name="android.permission.READ_CONTACTS"/>

     <application
       android:icon="@drawable/ic_launcher"
       android:label="@string/app_name" >
       <activity
           android:label="@string/app_name"
           android:name=".ProviderActivity" >
           <intent-filter >
               <action android:name="android.intent.action.MAIN" />

               <category android:name="android.intent.category.LAUNCHER" />
           </intent-filter>
       </activity>
   </application>
</manifest>

• Back to ContentProvider  ↑