How to shrink resources and remove unused language resources with Android.mk

Question

I am working on AOSP Settings application which builds properly.

I am trying to build "user build" and have enabled proguard using proguard.flags and disabled jack compilation

ANDROID_COMPILE_WITH_JACK := false
LOCAL_PROGUARD_FLAG_FILES := proguard.flags

My question is how can I shrink resources and strip/remove unneeded language string resources that we generally do in build.gradle using Android.mk file

android {
    buildTypes {
        release {
            // Enables code shrinking, obfuscation, and optimization for only
            // your project's release build type.
            minifyEnabled true

            // Enables resource shrinking, which is performed by the
            // Android Gradle plugin.
            shrinkResources true
        }
    }
}

And to keep only US and Indian English

android {
    defaultConfig {
        resConfigs "en_US", "en_IN"
    }
}

My Android.mk file

LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)

LOCAL_SRC_FILES := \
        $(call all-logtags-files-under, src)

LOCAL_MODULE := settings-logtags

include $(BUILD_STATIC_JAVA_LIBRARY)

# Build the Settings APK
include $(CLEAR_VARS)

LOCAL_PACKAGE_NAME := Settings
LOCAL_PRIVATE_PLATFORM_APIS := true
LOCAL_CERTIFICATE := platform
LOCAL_PRODUCT_MODULE := true
LOCAL_PRIVILEGED_MODULE := true
LOCAL_REQUIRED_MODULES := privapp_whitelist_com.android.settings
LOCAL_MODULE_TAGS := optional
LOCAL_USE_AAPT2 := true

LOCAL_SRC_FILES := $(call all-java-files-under, src)

LOCAL_STATIC_ANDROID_LIBRARIES := \
    androidx-constraintlayout_constraintlayout \
    androidx.slice_slice-builders \
    androidx.slice_slice-core \
    androidx.slice_slice-view \
    androidx.core_core \
    androidx.appcompat_appcompat \
    androidx.cardview_cardview \
    androidx.preference_preference \
    androidx.recyclerview_recyclerview \
    com.google.android.material_material \
    setupcompat \
    setupdesign

LOCAL_JAVA_LIBRARIES := \
    telephony-common \
    ims-common

LOCAL_STATIC_JAVA_LIBRARIES := \
    androidx-constraintlayout_constraintlayout-solver \
    androidx.lifecycle_lifecycle-runtime \
    androidx.lifecycle_lifecycle-extensions \
    guava \
    jsr305 \
    settings-contextual-card-protos-lite \
    settings-log-bridge-protos-lite \
    contextualcards \
    settings-logtags \
    zxing-core-1.7

LOCAL_PROGUARD_FLAG_FILES := proguard.flags

ANDROID_COMPILE_WITH_JACK := false

include frameworks/base/packages/SettingsLib/common.mk
include frameworks/base/packages/SettingsLib/search/common.mk

include $(BUILD_PACKAGE)

# ====  prebuilt library  ========================
include $(CLEAR_VARS)

LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES := \
    contextualcards:libs/contextualcards.aar
include $(BUILD_MULTI_PREBUILT)

# Use the following include to make our test apk.
ifeq (,$(ONE_SHOT_MAKEFILE))
include $(call all-makefiles-under,$(LOCAL_PATH))
endif

My proguard.flags file

# Some tests use thenThrow from Mockito which require information on
# checked exceptions.
-keepattributes Exceptions

# Keep all Fragments in this package, which are used by reflection.
-keep public class com.android.settings.** extends androidx.fragment.app.Fragment

# Keep all preference controllers needed by slice and DashboardFragment.
-keep class * extends com.android.settings.core.BasePreferenceController {
    *;
}

-keep class * extends com.android.settings.core.TogglePreferenceController {
    *;
}

# We want to keep methods in Activity that could be used in the XML attribute onClick.
-keepclassmembers class * extends android.app.Activity {
    public void *(android.view.View);
    public void *(android.view.MenuItem);
}

# Keep setters in Views so that animations can still work.
-keep public class * extends android.view.View {
    public <init>(android.content.Context);
    public <init>(android.content.Context, android.util.AttributeSet);
    public <init>(android.content.Context, android.util.AttributeSet, int);

    void set*(***);
    *** get*();
}

# Keep classes that may be inflated from XML.
-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet);
}
-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}
-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int, int);
}

# Keep annotated classes or class members.
-keep @androidx.annotation.Keep class *
-keepclassmembers class * {
    @androidx.annotation.Keep *;
}

# Keep specific fields used via reflection.
-keepclassmembers class * {
    public static ** SEARCH_INDEX_DATA_PROVIDER;
    public static ** SUMMARY_PROVIDER_FACTORY;
}
-keep class androidx.core.app.CoreComponentFactory

# Keep classes that implements CustomSliceable, which are used by reflection.
-keepclasseswithmembers class * implements com.android.settings.slices.CustomSliceable {
    public <init>(android.content.Context);
}

# Keep classes that extends SliceBackgroundWorker, which are used by reflection.
-keepclasseswithmembers class * extends com.android.settings.slices.SliceBackgroundWorker {
    public <init>(android.content.Context, android.net.Uri);
}

documentation of

• Android.mk
• Application.mk
• Proguard

Answer 1

You cannot set for one app, but you can set PRODUCT_LOCALES in device or product level, which will take effect for all apps built with aosp.

Take the following as example, it will only include en_US and en_IN.

PRODUCT_LOCALES := en_US en_IN