Syncing data - from android client to cloud

I finally set up all the components for syncing data from my android client to the cloud.

• With Google App Engine, I can store backed-up data in the cloud and allow users to see different views of their data via a web browser.
• With the Cloud Endpoints Api, I can securely send data from my android client to my Google App Engine app.
• In my android client, I imported the Endpoints library code to send data to the cloud.

Now that I got all of my pieces working for data syncing, I should be done, right?  Actually, there's still a lot of work needed to set up the syncing for real Android users.  When should I send data?  Once a day? Once an hour?  How can I make it easy for users to customize how their app is synced?

Making the wrong decisions on syncing data can have a lot of adverse effects.  This may lead to problems on my Android app, my AppEngine app, and/or both.  Luckily, someone else realized that syncing is a critical issue and spent time working on some general solutions to this problem.

• http://developer.android.com/training/sync-adapters/index.html

I haven't had a chance to read through it all, but hopefully I can adjust my code to work with this sync-adapter framework.  Even if it doesn't work with what I have now, I'm sure I'll learn some important concepts that will help me make a good syncing solution.