I didn't realize you were wanting to do a full justify. Android does not support this in a textview. Some folks over at stack overflow found a hacked way to do it using HTML/webview instead of a textview.. http://stackoverflow.com/questions/1292575/android-textview-justify-text
The only other solution I can think of would be to change your font size to fill the width, but that would not work for very many use-cases.