How to sync contacts Android

Hi,

Source Code Link: https://github.com/JohnnyIqbal/ContactSyncBG

Please add appcomapt library to run this project.

This is ContactSyncBackground Demo as you see whatsapp,viber or other apps

I followed this process to achieve syncing in background

1. Create AuthenticatorService and ContactsSyncAdapter Service class.
AuthenticatorService Class is for when you create syncing account then this service run
so you can perform any operation during creating account or add account in setting.

2. To create account

SyncUtils.CreateAccount(instance, user, pass);

3. When account created successfully then you want to sync your contacts, ContactsSyncAdapterService is run when you perform syncing either manually(using setting) or automatically.

4. To perform syncing automatically

 AccountManager am = AccountManager.get(instance);  
  Account[] acclist = am.getAccounts();  
  for (Account acc : acclist) {  
   if (acc.type.equals(SyncUtils.ACCOUNT_TYPE)) {  
   // You need pass bundle to sync  
   Bundle b = new Bundle();  
   b.putBoolean(ContentResolver.SYNC_EXTRAS_MANUAL, true);  
   b.putBoolean(ContentResolver.SYNC_EXTRAS_EXPEDITED, true);  
   ContentResolver.requestSync(acc, SyncUtils.AUTHORITY, b);  
   Log.i("MainActivity", "Request to sync Contacts");  
   }  
  }  

5. After firing this operation onPerformSync() method called in ContactsSyncAdapterService
   Here you can perform network syncing operation. I poupulated the contacts in json and post to server
   and server returning me intersection of contacts.
 
6. You need to register this service in Manifiest

  <service  
       android:name="com.iqbal.contactsyncbg.sync.ContactsSyncAdapterService"  
       android:exported="true"  
       android:process=":contacts" >  
       <intent-filter>  
         <action android:name="android.content.SyncAdapter" />  
       </intent-filter>  
       <meta-data  
         android:name="android.content.SyncAdapter"  
         android:resource="@xml/sync_contacts" />  
       <meta-data  
         android:name="android.provider.CONTACTS_STRUCTURE"  
         android:resource="@xml/contacts" />  
     </service>  
     <service  
       android:name="com.iqbal.contactsyncbg.sync.AuthenticatorService"  
       android:exported="true"  
       android:process=":auth" >  
       <intent-filter>  
         <action android:name="android.accounts.AccountAuthenticator" />  
       </intent-filter>  
       <meta-data  
         android:name="android.accounts.AccountAuthenticator"  
         android:resource="@xml/authenticator" />  
     </service>  

 7. Be sure of Account Type what you defined in sync_contacts and ContactSyncAdapter must be same.
  Otherwise you will get this exception caller uid is different than the authenticator's uid to fix
  this exception you need to check account type.
     
 8. At last you need to add permission

 <uses-permission android:name="android.permission.READ_CONTACTS" />  
 <uses-permission android:name="android.permission.WRITE_CONTACTS" />  
 <uses-permission android:name="android.permission.GET_ACCOUNTS" />  
 <uses-permission android:name="android.permission.MANAGE_ACCOUNTS" />  
 <uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS" />  
 <uses-permission android:name="android.permission.READ_SYNC_SETTINGS" />  
 <uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />