Use a SpannableString. Also have a look at this tutorial.http://blog.stylingandroid.com/archives/177.
String tempString="Copyright";
TextView text=(TextView)findViewById(R.id.text);
SpannableString spanString = new SpannableString(tempString);
spanString.setSpan(new UnderlineSpan(), 0, spanString.length(), 0);
spanString.setSpan(new StyleSpan(Typeface.BOLD), 0, spanString.length(), 0);
spanString.setSpan(new StyleSpan(Typeface.ITALIC), 0, spanString.length(), 0);
text.setText(spanString);
You can also use different color for text's in textview.
SpannableString text = new SpannableString("Lorem ipsum dolor sit amet");
// make "Lorem" (characters 0 to 5) red
text.setSpan(new ForegroundColorSpan(Color.RED), 0, 5, 0);
textView.setText(text, BufferType.SPANNABLE);
http://www.chrisumbel.com/article/android_textview_rich_text_spannablestring. The link gives you more example of styling using spannable string.