How to add an app with Android Room as a system app compiled with the makefile?

Question

Trying to install a simple app that uses the Android Room to build a database, as a system app in AOSP. Stuck at what to include in the Android.mk makefile.

LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES := $(call all-java-files-under,src)
LOCAL_RESOURCE_DIR := /home/<username>/WORKING_DIRECTORY/packages/apps/appname/res
LOCAL_PROGUARD_ENABLED := disabled
LOCAL_MODULE_TAGS := optional
LOCAL_USE_AAPT2 := true
LOCAL_STATIC_JAVA_LIBRARIES := \
    android-common 

LOCAL_STATIC_ANDROID_LIBRARIES := \
    androidx.annotation_annotation \
    androidx.legacy_legacy-support-core-ui \
    androidx.appcompat_appcompat \
    androidx.core_core \
    androidx.recyclerview_recyclerview \
    androidx.room_room-common \
    androidx.room_room-migration \
    androidx.room_room-runtime \
    androidx.room_room-testing \
    android-support-annotations \
    androidx.cursoradapter_cursoradapter \
    androidx.sqlite_sqlite \
    androidx.sqlite_sqlite-framework \
    androidx.lifecycle_lifecycle-common \
    androidx.lifecycle_lifecycle-common-java8 \
    androidx.lifecycle_lifecycle-runtime \
    androidx.lifecycle_lifecycle-service 

LOCAL_ANNOTATION_PROCESSOR_CLASSES := \
    androidx.room.RoomProcessor

LOCAL_PACKAGE_NAME := com.app.appname
LOCAL_PRIVATE_PLATFORM_APIS := true
LOCAL_CERTIFICATE := platform
LOCAL_PRIVILEGED_MODULE := true

include $(BUILD_PACKAGE)

However, upon running the emulator after "make -j4" it gives the error -

E AndroidRuntime: java.lang.RuntimeException: cannot find implementation for com.app.appname.RoleManagerDB. RoleManagerDB_Impl does not exist

E AndroidRuntime: at com.app.appname.RoleManagerDB.getDatabase(RoleManagerDB.java:27) E AndroidRuntime: at com.app.appname.MainActivity.lambda$onCreate$0$MainActivity(MainActivity.java:28)

E AndroidRuntime: at com.app.appname.-$$Lambda$MainActivity$xxx.run(Unknown Source:4) W ActivityTaskManager: Force finishing activity com.app.appname/.MainActivity

My app compiles and runs smoothly on Android Studio, so what am I missing in the makefile?

My guess is I cannot seem to translate the gradle line:

annotationProcessor "androidx.room:room-compiler:$room_version"

to its makefile equivalent. Any help is much appreciated!

yes that might be the issue. before compilation android studio does the annotation processing which creates the necessary files like the implmentations of the room interfaces. so google about annotation processing in android.mk — Harkal, Oct 11 '20 at 18:41
@Harkal Yes I did that however I did not encounter a correct annotation processor statement for Android.mk file. I tried: "androidx.room_room-compiler-nodeps" "androidx.annotation_annotation" and "android-arch-room-rxjava2" yet it failed. — SamT01, Oct 11 '20 at 22:43

score 2 · Accepted Answer · edited May 17 '21 at 01:18

I had a lot of trouble finding information about this too.

The Android 10 Bluetooth Application uses Room, and the AnnotationProcessor is configured in its makefile (https://cs.android.com/android/platform/superproject/+/android-10.0.0_r30:packages/apps/Bluetooth/Android.mk)

In my module, I added:

include $(CLEAR_VARS)

...

LOCAL_ANNOTATION_PROCESSORS := annotation
LOCAL_ANNOTATION_PROCESSORS += room-common
LOCAL_ANNOTATION_PROCESSORS += room-compiler
LOCAL_ANNOTATION_PROCESSORS += room-migration
LOCAL_ANNOTATION_PROCESSORS += s-antlr4         # a later version of antlr4 is already on the classpath, be we want this version
LOCAL_ANNOTATION_PROCESSORS += apache-commons-codec
LOCAL_ANNOTATION_PROCESSORS += auto-common
LOCAL_ANNOTATION_PROCESSORS += s-javapoet       #the name javapoet is already defined - prefix for uniqueness
LOCAL_ANNOTATION_PROCESSORS += kotlin-metadata
LOCAL_ANNOTATION_PROCESSORS += sqlite-jdbc
LOCAL_ANNOTATION_PROCESSORS += jetbrain-annotations
LOCAL_ANNOTATION_PROCESSORS += guava-21.0
LOCAL_ANNOTATION_PROCESSORS += kotlin-stdlib

LOCAL_ANNOTATION_PROCESSOR_CLASSES := androidx.room.RoomProcessor


...

include $(BUILD_PACKAGE)

I also added a new module:

#These libraries get copied into out/host/common/obj/JAVA_LIBRARIES/
# and are required for annotation processing
include $(CLEAR_VARS)

LOCAL_LIBS_PATH := libs
COMMON_LIBS_PATH := ../../../prebuilts/tools/common/m2/repository

LOCAL_PREBUILT_STATIC_JAVA_LIBRARIES := \
        annotation:$(LOCAL_LIBS_PATH)/annotation-1.0.0-beta01.jar \
        room-common:$(LOCAL_LIBS_PATH)/room-common-2.0.0-beta01.jar \
        room-compiler:$(LOCAL_LIBS_PATH)/room-compiler-2.0.0-beta01.jar \
        room-migration:$(LOCAL_LIBS_PATH)/room-migration-2.0.0-beta01.jar \
        s-antlr4:$(COMMON_LIBS_PATH)/org/antlr/antlr4/4.5.3/antlr4-4.5.3.jar \
        apache-commons-codec:$(COMMON_LIBS_PATH)/org/eclipse/tycho/tycho-bundles-external/0.18.1/eclipse/plugins/org.apache.commons.codec_1.4.0.v201209201156.jar \
        auto-common:$(COMMON_LIBS_PATH)/com/google/auto/auto-common/0.9/auto-common-0.9.jar \
        s-javapoet:$(COMMON_LIBS_PATH)/com/squareup/javapoet/1.8.0/javapoet-1.8.0.jar \
        jetbrain-annotations:$(COMMON_LIBS_PATH)/org/jetbrains/annotations/13.0/annotations-13.0.jar \
        kotlin-metadata:$(COMMON_LIBS_PATH)/me/eugeniomarletti/kotlin-metadata/1.2.1/kotlin-metadata-1.2.1.jar \
        sqlite-jdbc:$(COMMON_LIBS_PATH)/org/xerial/sqlite-jdbc/3.20.1/sqlite-jdbc-3.20.1.jar
include $(BUILD_HOST_PREBUILT)

I stuck with the library versions that were used by Bluetooth on my device - I experienced dependency conflicts once I started upgrading libraries.

How to add an app with Android Room as a system app compiled with the makefile?

1 Answers1