<ScrollView
         android:id="@+id/scrollView_showMessages"
         android:layout_width="fill_parent"
         android:layout_height="310dp"
         >
         <TextView
                   android:id="@+id/textView_showMessages"
                   android:layout_width="fill_parent"
                   android:layout_height="wrap_content"
                   android:textSize="25dp"
                   />
</ScrollView>

mScrollView_showMessages=(ScrollView) findViewById(R.id.scrollView_showMessages);

mScrollView_showMessages.scrollTo(0, mTextView_showMessages.getBottom());