Query Contacts database

This exercise demonstrate how to query Contacts database directly, to retrieve _ID and DISPLAY_NAME.

package com.example.androidquerycontacts;

import android.net.Uri;
import android.os.Bundle;
import android.provider.ContactsContract;
import android.provider.ContactsContract.Contacts;
import android.support.v4.content.CursorLoader;
import android.app.Activity;
import android.database.Cursor;
import android.widget.TextView;

public class MainActivity extends Activity {
 
 TextView textContacts;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  textContacts = (TextView)findViewById(R.id.contacts);
  
  Uri queryUri = ContactsContract.Contacts.CONTENT_URI;
  String[] projection = new String[] {
    ContactsContract.Contacts._ID,
    ContactsContract.Contacts.DISPLAY_NAME};
  String selection = ContactsContract.Contacts.DISPLAY_NAME + " IS NOT NULL";
  
  CursorLoader cursorLoader = new CursorLoader(
            this, 
            queryUri, 
            projection, 
            selection, 
            null, 
            null);
  
  Cursor cursor = cursorLoader.loadInBackground();
  
  int columnIndex_ID = cursor.getColumnIndex(Contacts._ID);
  int columnIndex_DISPLAYNAME = cursor.getColumnIndex(Contacts.DISPLAY_NAME);
  
  String myContacts = "Contacts:\n";
  
  while(cursor.moveToNext()){
   int id = cursor.getInt(columnIndex_ID);
   String displayName = cursor.getString(columnIndex_DISPLAYNAME);
   myContacts += String.valueOf(id) + " : " + displayName +"\n";
  }
  
  textContacts.setText(myContacts);
 }


}

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity" 
    android:orientation="vertical">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />
    <ScrollView 
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
        <TextView
        android:id="@+id/contacts"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    </ScrollView>
    

</LinearLayout>

Permission of "android.permission.READ_CONTACTS" is needed in AndroidManifest.xml.

Download the files.


Next:
- Query Contacts database for contacts with phone number only
- Query Contacts database, search with selection of LIKE cause
- Query Contacts database, selection with AND to combine more cause
- Query Contacts database, display in ListView
- Handle Item Click on Query Contacts database ListView
- Access ContactsContract.CommonDataKinds.Phone via LOOKUP_KEY
- Get Email from Contacts database