I have implemented a custom account for an app I'm working on. Here is my authenticator.xml:
<?xml version="1.0" encoding="utf-8"?>
<account-authenticator xmlns:android="http://schemas.android.com/apk/res/android"
android:accountType="MyApp"
android:icon="@drawable/logo"
android:smallIcon="@drawable/logo"
android:label="MyApp"
android:accountPreferences="@xml/account_preferences" />
I can add the account using the Android setting's "Add Account" feature, and my app can use all the account's information. However the account doesn't ever show in the list with my Google, Twitter, Faceboock, etc. accounts.