this is MainActivity.kt before
var spannable = SpannableStringBuilder("$noColorText$coloredText")
spannable.setSpan(
ForegroundColorSpan(ContextCompat.getColor(textView.context, R.color.mainGreen)),
noColorText.length, spannable.length,
Spannable.SPAN_EXCLUSIVE_INCLUSIVE
)
spannable.setSpan(
StyleSpan(BOLD),
noColorText.length, spannable.length,
Spannable.SPAN_EXCLUSIVE_INCLUSIVE
)
textView.text = spannable
Here's my approach so far.
Extension.kt
// TODO: e.g: "string".putSpans(start, end, flags) { ForgroundColorSpan(color), StyleSpan(BOLD) }
fun String.putSpans(vararg flags: Int.() -> Unit, spanBuilder: SpannableStringBuilder.() -> Unit):
SpannableStringBuilder = SpannableStringBuilder(this).apply(spanBuilder)
MainActivity.kt
// TODO: Change SpannableBuilder to be modular (without, reinput duplicate args)
val resultSpan = "$noColorText$coloredText ".putSpans {
setSpan(ForegroundColorSpan(ContextCompat.getColor(textView.context, R.color.mainGreen)),
noColorText.length, this.length, // this is duplicate
Spannable.SPAN_EXCLUSIVE_INCLUSIVE) // this is duplicate
setSpan(StyleSpan(BOLD),
noColorText.length, this.length, // this is duplicate
Spannable.SPAN_EXCLUSIVE_INCLUSIVE) // this is duplicate
}
textView.text = resultSpan
Is this possible to create extension like this
"string".putSpans(start, end, flags) { ForgroundColorSpan(color), StyleSpan(BOLD) }
so we don't have to use duplicate start, end, also flags argument, but open for modification, e.g:
"string".putSpans(start, end, flags) { // for default value
span(ForgroundColorSpan(color), diffStart, diffEnd),
span(StyleSpan(BOLD), diffFlags)
}
You can use extensions included in core-ktx
which simplify using, more specifically, building SpannedString
in kotlin as so:
buildSpannedString {
bold {
append("hitherejoe")
}
}
I guess you would use it like this:
buildSpannedString {
bold {
inSpans(ForegroundColorSpan(ContextCompat.getColor(textView.context, R.color.mainGreen))) {
append("string")
}
}
}
See androidx.text package for reference.
I took the example from this Medium post by Joe Birch.