We only tested the update downloading with app sizes in the kilobytes, which I admit is not the most practical. 

I've got some cleanup code in the update call to make sure the App is valid (MD5 check from the file on the server should be sufficient.) But as for best practices involving, say, the user prompting a 30MB app download and then stopping the app, I have only my experiences and assumptions. 

Don't we need the UI thread if we want to prompt an alert dialog? We'll need an Activity if we want to use runOnUiThread.  (This was an axis to my original indecision of Context vs Activity)