I don't do anything with keyboard from my code, and I can't reproduce it on my phone running Android 2.3. But I saw it on tablet, keyboard pop-up when my app is started. What can cause this?
The keyboard might be triggered when an EditText gets focus as soon as your activity opens. I also faced this and fixed it by hiding the soft keyboard when the activity is created. Try adding the following code in onCreate:
getWindow().setSoftInputMode(
WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);