(TextView) newText.setText(getString(R.string.textstr1) + getString(R.string.textstr2) + getString(R.string.textstr3));

<string name="text">This is <i>italic</i></string>

<string name="text"><![CDATA[This is <i>italic</i>]]></string>

yourTextView.setText(Html.fromHtml(getString(R.string.text)));

String newString=getString(R.string.textstr1) + getString(R.string.textstr2) + getString(R.string.textstr3);

newText.setText(Html.fromHtml(newString));

(TextView) newText.setTextHtml.fromHtml((getString(R.string.textstr1) + getString(R.string.textstr2) + getString(R.string.textstr3)));