Android :: EditText Lose Focus When Keyboard Appears

I make ListView that has some items that has one EditText and one ImageButton. When touch the EditText in ListView's Item, Keyboard was appeared but EditText lose focus. What can I do for resolve this problem? I can use ScrollView instead of ListView by addView in ScrollView. And in ScrollView, when I touch the EditText, keyboard was appeared and EditText keep the focus. But I must optimize the list because the list may has many items. In ListView, I can optimize list in getView. But in ScrollVIew, there was not way to optimaize list. So, I must use ListView.