Extensão em Kotlin para converter String em SpannableString ou Vice-Versa.

SpannableExt.kt

import android.content.Context
import android.graphics.Typeface
import android.text.Spannable
import android.text.SpannableString
import android.text.style.ForegroundColorSpan
import android.text.style.StyleSpan
import android.text.style.TextAppearanceSpan
import androidx.annotation.ColorInt
import androidx.annotation.ColorRes
import androidx.core.content.ContextCompat

fun String.bold(): SpannableString {
    return SpannableString(this).apply {
        setSpan(StyleSpan(Typeface.BOLD), 0, this@bold.length, Spannable.SPAN_EXCLUSIVE_EXCLUSIVE)
    }
}

fun String.color(context: Context, @ColorRes color: Int): SpannableString {
    return SpannableString(this).apply {
        setSpan(
            ForegroundColorSpan(ContextCompat.getColor(context, color)),
            0,
            this@color.length,
            Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
        )
    }
}

fun String.color(@ColorInt color: Int): SpannableString {
    return SpannableString(this).apply {
        setSpan(
            ForegroundColorSpan(color),
            0,
            this@color.length,
            Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
        )
    }
}

fun String.textAppearance(context: Context, appearance: Int): SpannableString {
    return SpannableString(this).apply {
        setSpan(
            TextAppearanceSpan(context, appearance),
            0,
            this@textAppearance.length,
            Spannable.SPAN_EXCLUSIVE_EXCLUSIVE
        )
    }
}

//

fun SpannableString.bold(): SpannableString {
    return this.apply {
        setSpan(StyleSpan(Typeface.BOLD), 0, length, 0)
    }
}

fun SpannableString.color(context: Context, @ColorRes color: Int): SpannableString {
    return this.apply {
        setSpan(ForegroundColorSpan(ContextCompat.getColor(context, color)), 0, length, 0)
    }
}

fun SpannableString.color(@ColorInt color: Int): SpannableString {
    return this.apply {
        setSpan(ForegroundColorSpan(color), 0, length, 0)
    }
}

fun SpannableString.textAppearance(context: Context, appearance: Int): SpannableString {
    return this.apply {
        setSpan(TextAppearanceSpan(context, appearance), 0, length, 0)
    }
}