added the simplest example of contact sync that does nothing.

Author: yuki24

account-manager-example/AndroidManifest.xml

@@ -30,5 +30,11 @@
 			</intent-filter>
 			<meta-data android:name="android.accounts.AccountAuthenticator" android:resource="@xml/authenticator" />
 		</service>
+		<service android:name=".core.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/syncadapter" />
+		</service>
 	</application>
 </manifest>

account-manager-example/res/xml/syncadapter.xml

@@ -0,0 +1,5 @@
+<sync-adapter xmlns:android="http://schemas.android.com/apk/res/android"
+	android:contentAuthority="com.android.contacts"
+	android:accountType="net.yuki24.examples"
+	android:supportsUploading="false"
+	android:userVisible="true" />

account-manager-example/src/net/yuki24/examples/AccountManager/core/ContactsSyncAdapterService.java

@@ -0,0 +1,60 @@
+package net.yuki24.examples.AccountManager.core;
+
+import android.accounts.Account;
+import android.accounts.OperationCanceledException;
+import android.app.Service;
+import android.content.AbstractThreadedSyncAdapter;
+import android.content.ContentProviderClient;
+import android.content.ContentResolver;
+import android.content.Context;
+import android.content.Intent;
+import android.content.SyncResult;
+import android.os.Bundle;
+import android.os.IBinder;
+import android.util.Log;
+
+public class ContactsSyncAdapterService extends Service {
+	private static final String TAG = "ContactsSyncAdapterService";
+	private static SyncAdapterImpl sSyncAdapter = null;
+	private static ContentResolver mContentResolver = null;
+	 
+	public ContactsSyncAdapterService() {
+		super();
+	}
+	 
+	private static class SyncAdapterImpl extends AbstractThreadedSyncAdapter {
+		private Context mContext;
+	 
+		public SyncAdapterImpl(Context context) {
+			super(context, true);
+			mContext = context;
+		}
+	 
+		@Override
+		public void onPerformSync(Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult) {
+			try {
+				ContactsSyncAdapterService.performSync(mContext, account, extras, authority, provider, syncResult);
+			} catch (OperationCanceledException e) {
+			}
+		}
+	}
+	 
+	@Override
+	public IBinder onBind(Intent intent) {
+		IBinder ret = null;
+		ret = getSyncAdapter().getSyncAdapterBinder();
+		return ret;
+	}
+	 
+	private SyncAdapterImpl getSyncAdapter() {
+		if (sSyncAdapter == null) sSyncAdapter = new SyncAdapterImpl(this);
+		return sSyncAdapter;
+	}
+	 
+	private static void performSync(Context context, Account account, Bundle extras, String authority, ContentProviderClient provider, SyncResult syncResult)
+		throws OperationCanceledException {
+		mContentResolver = context.getContentResolver();
+		Log.i(TAG, "performSync: " + account.toString());
+		//This is where the magic will happen!
+	}
+}