CustomSpan, with the ability to set style from resource file and custom typeface. applyCustomTypeface() method taken from http://goo.gl/dtJulZ, TextApperanceSpan from android source code.

CustomTypefaceStyleSpan.java

import android.content.Context;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.text.TextPaint;
import android.text.style.TextAppearanceSpan;

/**
 * Created by bgorkowy on 2014-05-21.
 */
public class CustomTypefaceStyleSpan extends TextAppearanceSpan {
  private Typeface mNewTypeface;

  public CustomTypefaceStyleSpan(Context context, int appearance, Typeface typeface) {
    super(context, appearance);
    mNewTypeface = typeface;
  }

  @Override
  public void updateDrawState(TextPaint ds) {
    updateMeasureState(ds);

    if (getTextColor() != null) {
      ds.setColor(getTextColor().getColorForState(ds.drawableState, 0));
    }

    if (getLinkTextColor() != null) {
      ds.linkColor = getLinkTextColor().getColorForState(ds.drawableState, 0);
    }
  }

  @Override
  public void updateMeasureState(TextPaint ds) {
    applyCustomTypeFace(ds, mNewTypeface);

    if (getTextSize() > 0) {
      ds.setTextSize(getTextSize());
    }
  }

  private static void applyCustomTypeFace(Paint ds, Typeface tf) {
    int oldStyle;
    Typeface old = ds.getTypeface();
    if (old == null) {
      oldStyle = 0;
    } else {
      oldStyle = old.getStyle();
    }

    int fake = oldStyle & ~tf.getStyle();
    if ((fake & Typeface.BOLD) != 0) {
      ds.setFakeBoldText(true);
    }

    if ((fake & Typeface.ITALIC) != 0) {
      ds.setTextSkewX(-0.25f);
    }

    ds.setTypeface(tf);
  }

}