I have a string in my strings.xml
which is localized for different languages. The strings are styled with Html tags for each localization.
Using Android TextView
, I was able to show the styled text just fine by reading the string resources.
Considering that Jetpack Compose currently (1.0.0-rc02)
does not support Html tags, I tried using TextView
inside an AndroidView
composable following Official Docs: https://developer.android.com/jetpack/compose/interop/interop-apis#views-in-compose
Example of what I tried:
@Composable
fun StyledText(text: String, modifier: Modifier = Modifier) {
AndroidView(
modifier = modifier,
factory = { context -> TextView(context) },
update = {
it.text = HtmlCompat.fromHtml(html, HtmlCompat.FROM_HTML_MODE_COMPACT)
}
)
}
The text in strings.xml
file:
<string name="styled_text">Sample text with <b>bold styling</b> to test</string>
However, using stringResource(id = R.string.styled_text)
provides the text without the Html tags.
Is there a way to show text from string resources with Html styles in Jetpack Compose?
The following two questions are similar, but they do not read the string from resources:
stringResource
under the hood uses resources.getString
, which discards any styled information. You need to create something like textResource
to get the raw value:
@Composable
@ReadOnlyComposable
fun textResource(@StringRes id: Int): CharSequence =
LocalContext.current.resources.getText(id)
And use it like this:
StyledText(textResource(id = R.string.foo))
@Composable
fun StyledText(text: CharSequence, modifier: Modifier = Modifier) {
AndroidView(
modifier = modifier,
factory = { context -> TextView(context) },
update = {
it.text = text
}
)
}
Currently, you can use AnnotatedString
class in order to show styled test within a Text
component. I will show you an example:
Text(
text = buildAnnotatedString {
withStyle(style = SpanStyle(fontWeight = FontWeight.Thin)) {
append(stringResource(id = R.string.thin_string))
}
withStyle(style = SpanStyle(fontWeight = FontWeight.Bold)) {
append(stringResource(id = R.string.bold_string))
}
},
)
Depending on the style you assign, you will get a text with the style of the red highlight
https://i.stack.imgur.com/XSMMB.png
For more info: https://developer.android.com/jetpack/compose/text?hl=nl#multiple-styles
There is ongoing discussion to implement on Jetpack Compose UI: https://issuetracker.google.com/issues/139320238
After some research, I came me up with the following solution that I also posted in the same discussion:
@Composable
@ReadOnlyComposable
private fun resources(): Resources {
LocalConfiguration.current
return LocalContext.current.resources
}
fun Spanned.toHtmlWithoutParagraphs(): String {
return HtmlCompat.toHtml(this, HtmlCompat.TO_HTML_PARAGRAPH_LINES_CONSECUTIVE)
.substringAfter("<p dir=\"ltr\">").substringBeforeLast("</p>")
}
fun Resources.getText(@StringRes id: Int, vararg args: Any): CharSequence {
val escapedArgs = args.map {
if (it is Spanned) it.toHtmlWithoutParagraphs() else it
}.toTypedArray()
val resource = SpannedString(getText(id))
val htmlResource = resource.toHtmlWithoutParagraphs()
val formattedHtml = String.format(htmlResource, *escapedArgs)
return HtmlCompat.fromHtml(formattedHtml, HtmlCompat.FROM_HTML_MODE_LEGACY)
}
@Composable
fun annotatedStringResource(@StringRes id: Int, vararg formatArgs: Any): AnnotatedString {
val resources = resources()
val density = LocalDensity.current
return remember(id) {
val text = resources.getText(id, *formatArgs)
spannableStringToAnnotatedString(text, density)
}
}
@Composable
fun annotatedStringResource(@StringRes id: Int): AnnotatedString {
val resources = resources()
val density = LocalDensity.current
return remember(id) {
val text = resources.getText(id)
spannableStringToAnnotatedString(text, density)
}
}
private fun spannableStringToAnnotatedString(
text: CharSequence,
density: Density
): AnnotatedString {
return if (text is Spanned) {
with(density) {
buildAnnotatedString {
append((text.toString()))
text.getSpans(0, text.length, Any::class.java).forEach {
val start = text.getSpanStart(it)
val end = text.getSpanEnd(it)
when (it) {
is StyleSpan -> when (it.style) {
Typeface.NORMAL -> addStyle(
SpanStyle(
fontWeight = FontWeight.Normal,
fontStyle = FontStyle.Normal
),
start,
end
)
Typeface.BOLD -> addStyle(
SpanStyle(
fontWeight = FontWeight.Bold,
fontStyle = FontStyle.Normal
),
start,
end
)
Typeface.ITALIC -> addStyle(
SpanStyle(
fontWeight = FontWeight.Normal,
fontStyle = FontStyle.Italic
),
start,
end
)
Typeface.BOLD_ITALIC -> addStyle(
SpanStyle(
fontWeight = FontWeight.Bold,
fontStyle = FontStyle.Italic
),
start,
end
)
}
is TypefaceSpan -> addStyle(
SpanStyle(
fontFamily = when (it.family) {
FontFamily.SansSerif.name -> FontFamily.SansSerif
FontFamily.Serif.name -> FontFamily.Serif
FontFamily.Monospace.name -> FontFamily.Monospace
FontFamily.Cursive.name -> FontFamily.Cursive
else -> FontFamily.Default
}
),
start,
end
)
is BulletSpan -> {
Log.d("StringResources", "BulletSpan not supported yet")
addStyle(SpanStyle(), start, end)
}
is AbsoluteSizeSpan -> addStyle(
SpanStyle(fontSize = if (it.dip) it.size.dp.toSp() else it.size.toSp()),
start,
end
)
is RelativeSizeSpan -> addStyle(
SpanStyle(fontSize = it.sizeChange.em),
start,
end
)
is StrikethroughSpan -> addStyle(
SpanStyle(textDecoration = TextDecoration.LineThrough),
start,
end
)
is UnderlineSpan -> addStyle(
SpanStyle(textDecoration = TextDecoration.Underline),
start,
end
)
is SuperscriptSpan -> addStyle(
SpanStyle(baselineShift = BaselineShift.Superscript),
start,
end
)
is SubscriptSpan -> addStyle(
SpanStyle(baselineShift = BaselineShift.Subscript),
start,
end
)
is ForegroundColorSpan -> addStyle(
SpanStyle(color = Color(it.foregroundColor)),
start,
end
)
else -> addStyle(SpanStyle(), start, end)
}
}
}
}
} else {
AnnotatedString(text.toString())
}
}
Source: https://issuetracker.google.com/issues/139320238#comment11
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