Combining Spannable with String.format()

Question

Suppose you have the following string:

String s = \"The cold hand reaches for the %1$s %2$s Ellesse\'s\";
String old = \"old\"; 
String tan = \"tan\"; 
String fo         


        

Answer 1

I needed to replace %s placeholders in a String by a set of Spannables, and didn't find anything satisfying enough, so I implemented my own formatter as a kotlin String extension. Hopes it helps anyone.

fun String.formatSpannable(vararg spans: CharSequence?): Spannable {
    val result = SpannableStringBuilder()
    when {
        spans.size != this.split("%s").size - 1 ->
            Log.e("formatSpannable",
                    "cannot format '$this' with ${spans.size} arguments")
        !this.contains("%s") -> result.append(this)
        else -> {
            var str = this
            var spanIndex = 0
            while (str.contains("%s")) {
                val preStr = str.substring(0, str.indexOf("%s"))
                result.append(preStr)
                result.append(spans[spanIndex] ?: "")
                str = str.substring(str.indexOf("%s") + 2)
                spanIndex++
            }
            if (str.isNotEmpty()) {
                result.append(str)
            }
        }
    }
    return result
}

and then usage as follows

"hello %s kotlin %s world".formatSpannable(span0, span1)