SpannedGenerator.scala

object SpannedGenerator {
  private def span(style: Object, text: CharSequence) = {
    val s = new SpannableString(text)
    s.setSpan(style, 0, text.length(), Spanned.SPAN_INCLUSIVE_EXCLUSIVE)
    s
  }
  def textColor(color: Int, text: CharSequence) =
    span(new ForegroundColorSpan(color) , text)

  def bold(text: CharSequence) = span(new StyleSpan(Typeface.BOLD) , text)

  def italics(text: CharSequence) = span(new StyleSpan(Typeface.ITALIC), text)
}

case class SpannedGenerator(fmt: String) {
  def formatSpans(items: CharSequence*): Spanned = {
    val builder = new SpannableStringBuilder()
    val idx = fmt indexOf "%"

    formatNext(builder, fmt, 0, idx, items:_*)

    builder
  }

  private def formatNext(s: SpannableStringBuilder, fmt: String,
                 cur: Int, next: Int, items: CharSequence*) {
    if (next == -1) {
      s.append(fmt.substring(cur, fmt.length))
    } else {
      s.append(fmt.substring(cur, next))
      val space = fmt.indexWhere({ !_.isDigit }, next + 1)
      val number = fmt.substring(next + 1,
        if (space < 0) fmt.length else space).toInt
      s.append(items(number - 1))
      if (space > 0)
        formatNext(s, fmt, space, fmt indexOf ("%", space), items:_*)
    }
  }

}