Targeting Android 2.2
I have read the answers to the following questions:
Turn off autosuggest for EditText?
Android: Multiline & No autosuggest
You could simply use the EditText's setThreshold() method. Set the threshold to let's say 100 when you don't want to show predictions. If you want to re-activate showing predictions, set it back to a small int like 1 or 2 depending on your needs.
setThreshold()