Html.fromHtml barely has any documentations about which tags it supports.
It is written that it does support the "font" tag on many websites (like here), but I can't find out which fonts are available when setting "face" attribute within this tag.
Which fonts can I assume that are always available? Which of them are only from specific Android versions? Is there a list of them somewhere?
EDIT: it seems the answer should be in "/system/etc/fonts.xml" file. Here's its content on Android 6.0.1 :
<familyset version="22">
<!-- first font is default -->
<family name="sans-serif">
<font weight="100" style="normal">Roboto-Thin.ttf</font>
<font weight="100" style="italic">Roboto-ThinItalic.ttf</font>
<font weight="300" style="normal">Roboto-Light.ttf</font>
<font weight="300" style="italic">Roboto-LightItalic.ttf</font>
<font weight="400" style="normal">Roboto-Regular.ttf</font>
<font weight="400" style="italic">Roboto-Italic.ttf</font>
<font weight="500" style="normal">Roboto-Medium.ttf</font>
<font weight="500" style="italic">Roboto-MediumItalic.ttf</font>
<font weight="900" style="normal">Roboto-Black.ttf</font>
<font weight="900" style="italic">Roboto-BlackItalic.ttf</font>
<font weight="700" style="normal">Roboto-Bold.ttf</font>
<font weight="700" style="italic">Roboto-BoldItalic.ttf</font>
</family>
<!-- Note that aliases must come after the fonts they reference. -->
<alias name="sans-serif-thin" to="sans-serif" weight="100" />
<alias name="sans-serif-light" to="sans-serif" weight="300" />
<alias name="sans-serif-medium" to="sans-serif" weight="500" />
<alias name="sans-serif-black" to="sans-serif" weight="900" />
<alias name="arial" to="sans-serif" />
<alias name="helvetica" to="sans-serif" />
<alias name="tahoma" to="sans-serif" />
<alias name="verdana" to="sans-serif" />
<family name="sans-serif-condensed">
<font weight="300" style="normal">RobotoCondensed-Light.ttf</font>
<font weight="300" style="italic">RobotoCondensed-LightItalic.ttf</font>
<font weight="400" style="normal">RobotoCondensed-Regular.ttf</font>
<font weight="400" style="italic">RobotoCondensed-Italic.ttf</font>
<font weight="700" style="normal">RobotoCondensed-Bold.ttf</font>
<font weight="700" style="italic">RobotoCondensed-BoldItalic.ttf</font>
</family>
<alias name="sans-serif-condensed-light" to="sans-serif-condensed" weight="300" />
<family name="serif">
<font weight="400" style="normal">NotoSerif-Regular.ttf</font>
<font weight="700" style="normal">NotoSerif-Bold.ttf</font>
<font weight="400" style="italic">NotoSerif-Italic.ttf</font>
<font weight="700" style="italic">NotoSerif-BoldItalic.ttf</font>
</family>
<alias name="times" to="serif" />
<alias name="times new roman" to="serif" />
<alias name="palatino" to="serif" />
<alias name="georgia" to="serif" />
<alias name="baskerville" to="serif" />
<alias name="goudy" to="serif" />
<alias name="fantasy" to="serif" />
<alias name="ITC Stone Serif" to="serif" />
<family name="monospace">
<font weight="400" style="normal">DroidSansMono.ttf</font>
</family>
<alias name="sans-serif-monospace" to="monospace" />
<alias name="monaco" to="monospace" />
<family name="serif-monospace">
<font weight="400" style="normal">CutiveMono.ttf</font>
</family>
<alias name="courier" to="serif-monospace" />
<alias name="courier new" to="serif-monospace" />
<family name="casual">
<font weight="400" style="normal">ComingSoon.ttf</font>
</family>
<family name="cursive">
<font weight="400" style="normal">DancingScript-Regular.ttf</font>
<font weight="700" style="normal">DancingScript-Bold.ttf</font>
</family>
<family name="sans-serif-smallcaps">
<font weight="400" style="normal">CarroisGothicSC-Regular.ttf</font>
</family>
<!-- fallback fonts -->
<family variant="elegant">
<font weight="400" style="normal">NotoNaskhArabic-Regular.ttf</font>
<font weight="700" style="normal">NotoNaskhArabic-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoNaskhArabicUI-Regular.ttf</font>
<font weight="700" style="normal">NotoNaskhArabicUI-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansEthiopic-Regular.ttf</font>
<font weight="700" style="normal">NotoSansEthiopic-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansHebrew-Regular.ttf</font>
<font weight="700" style="normal">NotoSansHebrew-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansThai-Regular.ttf</font>
<font weight="700" style="normal">NotoSansThai-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansThaiUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansThaiUI-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansArmenian-Regular.ttf</font>
<font weight="700" style="normal">NotoSansArmenian-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansGeorgian-Regular.ttf</font>
<font weight="700" style="normal">NotoSansGeorgian-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansDevanagari-Regular.ttf</font>
<font weight="700" style="normal">NotoSansDevanagari-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansDevanagariUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansDevanagariUI-Bold.ttf</font>
</family>
<!-- Gujarati should come after Devanagari -->
<family variant="elegant">
<font weight="400" style="normal">NotoSansGujarati-Regular.ttf</font>
<font weight="700" style="normal">NotoSansGujarati-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansGujaratiUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansGujaratiUI-Bold.ttf</font>
</family>
<!-- Gurmukhi should come after Devanagari -->
<family variant="elegant">
<font weight="400" style="normal">NotoSansGurmukhi-Regular.ttf</font>
<font weight="700" style="normal">NotoSansGurmukhi-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansGurmukhiUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansGurmukhiUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansTamil-Regular.ttf</font>
<font weight="700" style="normal">NotoSansTamil-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansTamilUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansTamilUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansMalayalam-Regular.ttf</font>
<font weight="700" style="normal">NotoSansMalayalam-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansMalayalamUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansMalayalamUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansBengali-Regular.ttf</font>
<font weight="700" style="normal">NotoSansBengali-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansBengaliUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansBengaliUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansTelugu-Regular.ttf</font>
<font weight="700" style="normal">NotoSansTelugu-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansTeluguUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansTeluguUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansKannada-Regular.ttf</font>
<font weight="700" style="normal">NotoSansKannada-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansKannadaUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansKannadaUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansOriya-Regular.ttf</font>
<font weight="700" style="normal">NotoSansOriya-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansOriyaUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansOriyaUI-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansSinhala-Regular.ttf</font>
<font weight="700" style="normal">NotoSansSinhala-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansKhmer-Regular.ttf</font>
<font weight="700" style="normal">NotoSansKhmer-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansKhmerUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansKhmerUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansLao-Regular.ttf</font>
<font weight="700" style="normal">NotoSansLao-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansLaoUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansLaoUI-Bold.ttf</font>
</family>
<family variant="elegant">
<font weight="400" style="normal">NotoSansMyanmar-Regular.ttf</font>
<font weight="700" style="normal">NotoSansMyanmar-Bold.ttf</font>
</family>
<family variant="compact">
<font weight="400" style="normal">NotoSansMyanmarUI-Regular.ttf</font>
<font weight="700" style="normal">NotoSansMyanmarUI-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansThaana-Regular.ttf</font>
<font weight="700" style="normal">NotoSansThaana-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansCham-Regular.ttf</font>
<font weight="700" style="normal">NotoSansCham-Bold.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansBalinese-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansBamum-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansBatak-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansBuginese-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansBuhid-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansCanadianAboriginal-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansCherokee-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansCoptic-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansGlagolitic-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansHanunoo-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansJavanese-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansKayahLi-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansLepcha-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansLimbu-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansLisu-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansMandaic-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansMeeteiMayek-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansNewTaiLue-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansNKo-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansOlChiki-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansRejang-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansSaurashtra-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansSundanese-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansSylotiNagri-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansSyriacEstrangela-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansTagbanwa-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansTaiTham-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansTaiViet-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansTibetan-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansTifinagh-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansVai-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansYi-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansSymbols-Regular-Subsetted.ttf</font>
</family>
<family lang="zh-Hans">
<font weight="400" style="normal">NotoSansSC-Regular.otf</font>
</family>
<family lang="zh-Hant">
<font weight="400" style="normal">NotoSansTC-Regular.otf</font>
</family>
<family lang="ja">
<font weight="400" style="normal">NotoSansJP-Regular.otf</font>
</family>
<family lang="ko">
<font weight="400" style="normal">NotoSansKR-Regular.otf</font>
</family>
<family>
<font weight="400" style="normal">NanumGothic.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoColorEmoji.ttf</font>
</family>
<family>
<font weight="400" style="normal">DroidSansFallback.ttf</font>
</family>
<family lang="ja">
<font weight="400" style="normal">MTLmr3m.ttf</font>
</family>
<!--
Tai Le and Mongolian are intentionally kept last, to make sure they don't override
the East Asian punctuation for Chinese.
-->
<family>
<font weight="400" style="normal">NotoSansTaiLe-Regular.ttf</font>
</family>
<family>
<font weight="400" style="normal">NotoSansMongolian-Regular.ttf</font>
</family>
</familyset>
Using the "/system/etc/fonts.xml" file, I've created this code:
textView.setText(Html.fromHtml("Normal <br/>" +
"<font face='sans-serif'>sans-serif</font> <br/>" +
"<font face='sans-serif-thin'>sans-serif-thin</font> <br/>" +
"<font face='sans-serif-light'>sans-serif-light</font> <br/>" +
"<font face='sans-serif-medium'>sans-serif-medium</font> <br/>" +
"<font face='sans-serif-black'>sans-serif-black</font> <br/>" +
"<font face='sans-serif-condensed'>sans-serif-condensed</font> <br/>" +
"<font face='sans-serif-condensed-light'>sans-serif-condensed-light</font> <br/>" +
"<font face='serif'>serif</font> <br/>" +
"<font face='monospace'>monospace</font> <br/>" +
"<font face='serif-monospace'>serif-monospace</font> <br/>" +
"<font face='casual'>casual</font> <br/>" +
"<font face='cursive'>cursive</font> <br/>" +
"<font face='sans-serif-smallcaps'>sans-serif-smallcaps</font> <br/>" +
"<font face='elegant'>elegant</font> <br/>" +
"<font face='compact'>compact</font> <br/>"
));
And here is the result:
So it seems that all of those are supported, except maybe "elegant" and "compact", which don't seem to be real fonts there (so maybe I didn't understand their purpose).
Also, this was tested on Android 6.0.1 . I wonder how well it works on older versions, which are available there, and if there are new ones in Android N.
Here's the result of running this code on Android 4.0 emulator:
seems that it doesn't have most of the fonts.
And here is what I see for Xperia J with Android 4.1.2 :
So here it seems a bit more fonts became available.