Locales and Android Support

Android supports only a subset of the locales found in Java's Locale API, which uses the BCP47 spec for its language tags. However, Android uses a slight variation of the spec as seen below.

It is not always clear which language tags will compile with each formatting when adding them as resourceConfigurations and may require some experimentation.

• All Java locales
• Known Android-supported locales

Java Locale dash format (standard BCP47)

xx-Yyyy-ZZ

• xx = country code
• Yyyy = script code
• ZZ = region code

Script and region codes are optional, and the following examples are all correct.

tag	locale
es	español
fr-CH	français (Suisse)
sr-Latn	srpski (latinica)
az-Cyrl-AZ	азәрбајҹан (Кирил,Азәрбајҹан)

Android -r format

It seems Android generally doesn't support script codes in resourceConfigurations language tags, with one known exception below. This is possibly due to the need for the language tags to align with localized build resources, which were implemented differently (speculation). Most supported tags can be converted from 'Java dash' to this '-r' format.

xx-rZZ

• xx = country code
• r = resource (maybe?)
• ZZ = region code

Region codes are generally optional, but some tags will fail to compile with only the country code.

tag	locale
es	español
fr-rCH	français (Suisse)
sr-Latn	srpski (latinica)
az-Cyrl-AZ	doesn't compile

Android also has its own variation of some language tags that do not appear in the Locale API.

tag	locale
zh	中文
zh-rCN	中文 (中国)
zh-rTW	中文 (台灣)

Android b+ format

Another supported variation is the 'b+' format Android uses for locale resolution since API level 24. Some experimentation may be needed to determine if a resourceConfigurations will compile with 'b+' or '-r' formatting.

tag	locale
b+de+DE	Deutsch (Deutschland)
b+es	español
b+fr+CH	français (Suisse)
b+sr+Latn	srpski (latinica)