Changing the Android emulator locale automatically

Personally I think the simplest way is to start the emulator, probably a clean instance unless you are running integration tests that depends on other applications and then change locale using adb:

$ adb shell 'setprop persist.sys.language en;setprop persist.sys.country GB;stop;sleep 5;start'

or whatever locale you want to set.To verify that your change was successful just use

$ adb shell 'getprop persist.sys.language'

You may also want to run emulators on know ports, check my answer in this thread.

Note that you can also set system properties directly when starting the emulator:

emulator -avd my_avd -prop persist.sys.language=en -prop persist.sys.country=GB

This way, you can create a plain old emulator of any type then start it up immediately using the locale of your choice, without first having to make any modifications to the emulator images.

This locale will persist for future runs of the emulator, though of course you can always change it again at startup or during runtime.

Accepted answer doesn't work anymore. persist.sys.language and persist.sys.country are gone from emulator properties.

My solution is to use preinstalled on android emulator "Custom locale" application. Simply send intent with extra language parameter to it as below:

adb shell am broadcast -a com.android.intent.action.SET_LOCALE --es com.android.intent.extra.LOCALE EN

More information here - prepare android emulator for UI test automation.

UPDATE: based on comment from Jonas Alves the following command works on API 28+:

adb shell am broadcast -a com.android.intent.action.SET_LOCALE --es com.android.intent.extra.LOCALE "en_US" com.android.customlocale2

Seems that Android emulator now supports setting the locale when starting it:

emulator -avd <avd-name> -change-locale fr-CA

Source - https://androidstudio.googleblog.com/2019/09/emulator-29112-stable.html