Make Java API available on Android (microsoft#3030)

BUILD.md

@@ -274,18 +274,18 @@ To build ONNX Runtime with the NN API EP, first install Android NDK (see [Androi
 
 #### Build Instructions
 
-The basic build commands are below. There are also some other parameters for building the Android version under See [Android Build instructions](#android) for more details.
+The basic build commands are below. There are also some other parameters for building the Android version. See [Android Build instructions](#android) for more details.
 
 ##### Cross compiling on Windows
 
 ```bash
-./build.bat --android --android_ndk_path <android ndk path> --dnnlibrary
+./build.bat --android --android_sdk_path <android sdk path> --android_ndk_path <android ndk path> --dnnlibrary
 ```
 
 ##### Cross compiling on Linux
 
 ```bash
-./build.sh --android --android_ndk_path <android ndk path> --dnnlibrary
+./build.sh --android --android_sdk_path <android sdk path> --android_ndk_path <android ndk path> --dnnlibrary
 ```
 
 ---
@@ -580,21 +580,22 @@ ls -l /code/onnxruntime/build/Linux/MinSizeRel/dist/*.whl
 
 #### Pre-Requisites
 
-Install Android NDK from https://developer.android.com/ndk/downloads
+Install Android NDK in Android Studio or https://developer.android.com/ndk/downloads
 
 #### Build Instructions
 
 ##### Cross compiling on Windows
 
 ```bash
-./build.bat --android --android_ndk_path <android ndk path> --android_abi <android abi, e.g., arm64-v8a (default) or armeabi-v7a> --android_api <android api level, e.g., 27 (default)>
+./build.bat --android --android_sdk_path <android sdk path> --android_ndk_path <android ndk path> --android_abi <android abi, e.g., arm64-v8a (default) or armeabi-v7a> --android_api <android api level, e.g., 27 (default)>
 ```
 
 ##### Cross compiling on Linux
 
 ```bash
-./build.sh --android --android_ndk_path <android ndk path> --android_abi <android abi, e.g., arm64-v8a (default) or armeabi-v7a> --android_api <android api level, e.g., 27 (default)>
+./build.sh --android --android_sdk_path <android sdk path> --android_ndk_path <android ndk path> --android_abi <android abi, e.g., arm64-v8a (default) or armeabi-v7a> --android_api <android api level, e.g., 27 (default)>
 ```
 
-If you want to use NNAPI Execution Provider on Android, see [docs/execution_providers/NNAPI-ExecutionProvider.md](/docs/execution_providers/NNAPI-ExecutionProvider.md).
+Android Archive (AAR) files, which can be imported directly in Android Studio, will be generated in your_build_dir/java/build/outputs/aar.
 
+If you want to use NNAPI Execution Provider on Android, see [docs/execution_providers/NNAPI-ExecutionProvider.md](/docs/execution_providers/NNAPI-ExecutionProvider.md).

cmake/CMakeLists.txt

@@ -279,7 +279,6 @@ if(onnxruntime_BUILD_SHARED_LIB OR onnxruntime_ENABLE_PYTHON)
     find_package(PythonLibs 3.5 REQUIRED)
   else()
     find_package(PythonInterp 3.4 REQUIRED)
-    find_package(PythonLibs 3.4 REQUIRED)
   endif()
 endif()
 

cmake/onnxruntime_java.cmake

@@ -6,9 +6,11 @@
 # Setup Java compilation
 include(FindJava)
 find_package(Java REQUIRED)
-find_package(JNI REQUIRED)
 include(UseJava)
-include_directories(${JNI_INCLUDE_DIRS})
+if (NOT CMAKE_SYSTEM_NAME STREQUAL "Android")
+    find_package(JNI REQUIRED)
+    include_directories(${JNI_INCLUDE_DIRS})
+endif()
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c11")
 
 set(JAVA_ROOT ${REPO_ROOT}/java)
@@ -81,16 +83,34 @@ onnxruntime_add_include_to_target(onnxruntime4j_jni onnxruntime_session)
 target_include_directories(onnxruntime4j_jni PRIVATE ${REPO_ROOT}/include ${JAVA_ROOT}/build/headers)
 target_link_libraries(onnxruntime4j_jni PUBLIC onnxruntime)
 
+set(JAVA_PACKAGE_OUTPUT_DIR ${JAVA_OUTPUT_DIR}/build)
+file(MAKE_DIRECTORY ${JAVA_PACKAGE_OUTPUT_DIR})
+if (CMAKE_SYSTEM_NAME STREQUAL "Android")
+    set(ANDROID_PACKAGE_OUTPUT_DIR ${JAVA_PACKAGE_OUTPUT_DIR}/android)
+    file(MAKE_DIRECTORY ${ANDROID_PACKAGE_OUTPUT_DIR})
+endif()
 # expose native libraries to the gradle build process
-file(MAKE_DIRECTORY ${JAVA_OUTPUT_DIR}/build)
 set(JAVA_PACKAGE_DIR ai/onnxruntime/native/)
 set(JAVA_NATIVE_LIB_DIR ${JAVA_OUTPUT_DIR}/native-lib)
 set(JAVA_NATIVE_JNI_DIR ${JAVA_OUTPUT_DIR}/native-jni)
 set(JAVA_PACKAGE_LIB_DIR ${JAVA_NATIVE_LIB_DIR}/${JAVA_PACKAGE_DIR})
 set(JAVA_PACKAGE_JNI_DIR ${JAVA_NATIVE_JNI_DIR}/${JAVA_PACKAGE_DIR})
 file(MAKE_DIRECTORY ${JAVA_PACKAGE_LIB_DIR})
 file(MAKE_DIRECTORY ${JAVA_PACKAGE_JNI_DIR})
+if (CMAKE_SYSTEM_NAME STREQUAL "Android")
+    set(ANDROID_PACKAGE_JNILIBS_DIR ${JAVA_OUTPUT_DIR}/android)
+    set(ANDROID_PACKAGE_ABI_DIR ${ANDROID_PACKAGE_JNILIBS_DIR}/${ANDROID_ABI})
+    file(MAKE_DIRECTORY ${ANDROID_PACKAGE_JNILIBS_DIR})
+    file(MAKE_DIRECTORY ${ANDROID_PACKAGE_ABI_DIR})
+endif()
 add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E create_symlink $<TARGET_FILE:onnxruntime> ${JAVA_PACKAGE_LIB_DIR}/$<TARGET_LINKER_FILE_NAME:onnxruntime>)
 add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E create_symlink $<TARGET_FILE:onnxruntime4j_jni> ${JAVA_PACKAGE_JNI_DIR}/$<TARGET_LINKER_FILE_NAME:onnxruntime4j_jni>)
+if (CMAKE_SYSTEM_NAME STREQUAL "Android")
+    add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E create_symlink $<TARGET_FILE:onnxruntime> ${ANDROID_PACKAGE_ABI_DIR}/$<TARGET_LINKER_FILE_NAME:onnxruntime>)
+    add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${CMAKE_COMMAND} -E create_symlink $<TARGET_FILE:onnxruntime4j_jni> ${ANDROID_PACKAGE_ABI_DIR}/$<TARGET_LINKER_FILE_NAME:onnxruntime4j_jni>)
+endif()
 # run the build process (this copies the results back into CMAKE_CURRENT_BINARY_DIR)
 add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${GRADLE_EXECUTABLE} cmakeBuild -DcmakeBuildDir=${CMAKE_CURRENT_BINARY_DIR} WORKING_DIRECTORY ${JAVA_ROOT})
+if (CMAKE_SYSTEM_NAME STREQUAL "Android")
+    add_custom_command(TARGET onnxruntime4j_jni POST_BUILD COMMAND ${GRADLE_EXECUTABLE} -b build-android.gradle -c settings-android.gradle build -DjniLibsDir=${ANDROID_PACKAGE_JNILIBS_DIR} -DbuildDir=${ANDROID_PACKAGE_OUTPUT_DIR} WORKING_DIRECTORY ${JAVA_ROOT})
+endif()

cmake/onnxruntime_unittests.cmake

@@ -574,6 +574,13 @@ add_test(NAME onnx_test_pytorch_converted
 add_test(NAME onnx_test_pytorch_operator
   COMMAND onnx_test_runner ${PROJECT_SOURCE_DIR}/external/onnx/onnx/backend/test/data/pytorch-operator)
 
+if (CMAKE_SYSTEM_NAME STREQUAL "Android")
+    list(APPEND android_shared_libs log android)
+    if (onnxruntime_USE_NNAPI)
+        list(APPEND android_shared_libs neuralnetworks)
+    endif()
+endif()
+
 #perf test runner
 set(onnxruntime_perf_test_src_dir ${TEST_SRC_DIR}/perftest)
 set(onnxruntime_perf_test_src_patterns
@@ -611,6 +618,9 @@ if (onnxruntime_BUILD_SHARED_LIB)
   if(NOT WIN32)
     list(APPEND onnxruntime_perf_test_libs nsync_cpp)
   endif()
+  if (CMAKE_SYSTEM_NAME STREQUAL "Android")
+    list(APPEND onnxruntime_perf_test_libs ${android_shared_libs})
+  endif()
   target_link_libraries(onnxruntime_perf_test PRIVATE ${onnxruntime_perf_test_libs} Threads::Threads)
   if(WIN32)
     target_link_libraries(onnxruntime_perf_test PRIVATE debug dbghelp advapi32)
@@ -650,6 +660,9 @@ if (onnxruntime_BUILD_SHARED_LIB)
   if(NOT WIN32)
     list(APPEND onnxruntime_shared_lib_test_LIBS nsync_cpp)
   endif()
+  if (CMAKE_SYSTEM_NAME STREQUAL "Android")
+    list(APPEND onnxruntime_shared_lib_test_LIBS ${android_shared_libs})
+  endif()
   AddTest(DYN
           TARGET onnxruntime_shared_lib_test
           SOURCES ${onnxruntime_shared_lib_test_SRC} ${TEST_SRC_DIR}/providers/test_main.cc

java/build-android.gradle

@@ -0,0 +1,69 @@
+apply plugin: 'com.android.library'
+
+def jniLibsDir = System.properties['jniLibsDir']
+def buildDir = System.properties['buildDir']
+
+project.buildDir = buildDir
+
+buildscript {
+	repositories {
+		google()
+		jcenter()
+	}
+	dependencies {
+		classpath 'com.android.tools.build:gradle:3.5.3'
+
+		// NOTE: Do not place your application dependencies here; they belong
+		// in the individual module build.gradle files
+	}
+}
+
+allprojects {
+	repositories {
+		google()
+		jcenter()
+	}
+}
+
+android {
+	compileSdkVersion 29
+	buildToolsVersion "29.0.2"
+
+	defaultConfig {
+		minSdkVersion 24
+		targetSdkVersion 28
+		versionCode 1
+		versionName "1.0"
+
+		testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+
+	}
+
+	android {
+		lintOptions {
+			abortOnError false
+		}
+	}
+	buildTypes {
+		release {
+			minifyEnabled false
+			proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+		}
+	}
+	compileOptions {
+		sourceCompatibility = 1.8
+		targetCompatibility = 1.8
+	}
+
+	sourceSets {
+		main {
+			jniLibs.srcDirs = [jniLibsDir]
+		}
+	}
+}
+
+dependencies {
+	testImplementation 'org.junit.jupiter:junit-jupiter-api:5.1.1'
+	testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.1.1'
+	testImplementation 'com.google.protobuf:protobuf-java:3.10.0'
+}

java/settings-android.gradle

@@ -0,0 +1,2 @@
+rootProject.name = 'onnxruntime'
+rootProject.buildFileName = 'build-android.gradle'

java/src/main/AndroidManifest.xml

@@ -0,0 +1,2 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="ai.onnxruntime" />

java/src/main/java/ai/onnxruntime/OnnxRuntime.java

@@ -44,14 +44,16 @@ static synchronized void init() throws IOException {
     if (loaded) {
       return;
     }
-    Path tempDirectory = Files.createTempDirectory("onnxruntime-java");
+    Path tempDirectory = isAndroid() ? null : Files.createTempDirectory("onnxruntime-java");
     try {
       load(tempDirectory, ONNXRUNTIME_LIBRARY_NAME);
       load(tempDirectory, ONNXRUNTIME_JNI_LIBRARY_NAME);
       ortApiHandle = initialiseAPIBase(ORT_API_VERSION_1);
       loaded = true;
     } finally {
-      cleanUp(tempDirectory.toFile());
+      if (!isAndroid()) {
+        cleanUp(tempDirectory.toFile());
+      }
     }
   }
 
@@ -72,6 +74,15 @@ private static void cleanUp(File file) {
     }
   }
 
+  private static boolean isAndroid() {
+    try {
+      Class.forName("android.app.Activity");
+      return true;
+    } catch (ClassNotFoundException e) {
+      return false;
+    }
+  }
+
   /**
    * Load a shared library by name.
    *
@@ -80,6 +91,12 @@ private static void cleanUp(File file) {
    * @throws IOException If the file failed to read or write.
    */
   private static void load(Path tempDirectory, String library) throws IOException {
+    // On Android, we simply use System.loadLibrary
+    if (isAndroid()) {
+      System.loadLibrary("onnxruntime4j_jni");
+      return;
+    }
+
     // 1) The user may skip loading of this library:
     String skip = System.getProperty("onnxruntime.native." + library + ".skip");
     if (Boolean.TRUE.toString().equalsIgnoreCase(skip)) {

tools/ci_build/build.py

@@ -120,6 +120,7 @@ def parse_arguments():
             help='')
     parser.add_argument("--android_api", type=int, default=27,
             help='Android API Level, e.g. 21')
+    parser.add_argument("--android_sdk_path", type=str, help='Path to the Android SDK')
     parser.add_argument("--android_ndk_path", default="", help="Path to the Android NDK")
 
     # Arguments needed by CI
@@ -443,7 +444,7 @@ def clean_targets(cmake_path, build_dir, configs):
 
         run_subprocess(cmd_args)
 
-def build_targets(cmake_path, build_dir, configs, parallel):
+def build_targets(args, cmake_path, build_dir, configs, parallel):
     for config in configs:
         log.info("Building targets for %s configuration", config)
         build_dir2 = get_config_build_dir(build_dir, config)
@@ -463,7 +464,11 @@ def build_targets(cmake_path, build_dir, configs, parallel):
             cmd_args += [ "--" ]
             cmd_args += build_tool_args
 
-        run_subprocess(cmd_args)
+        env = {}
+        if args.android:
+            env['ANDROID_SDK_ROOT']=args.android_sdk_path
+
+        run_subprocess(cmd_args, env=env)
 
 def add_dir_if_exists(dir, dir_list):
     if (os.path.isdir(dir)):
@@ -994,7 +999,7 @@ def main():
     setup_dml_build(args, cmake_path, build_dir, configs)
 
     if (args.build):
-        build_targets(cmake_path, build_dir, configs, args.parallel)
+        build_targets(args, cmake_path, build_dir, configs, args.parallel)
 
     if args.test :
         run_onnxruntime_tests(args, source_dir, ctest_path, build_dir, configs,

tools/ci_build/github/azure-pipelines/android-x86_64-crosscompile-ci-pipeline.yml

@@ -10,6 +10,6 @@ jobs:
       displayName: Clone submodules
     - script: echo "y" | $ANDROID_HOME/tools/bin/sdkmanager --install 'ndk-bundle'
       displayName: Install Android NDK
-    - script: tools/ci_build/build.py --android --build_dir build --android_ndk $ANDROID_HOME/ndk-bundle --android_abi=x86_64 --skip_submodule_sync --parallel --use_dnnlibrary
+    - script: tools/ci_build/build.py --android --build_dir build --android_sdk_path $ANDROID_HOME --android_ndk_path $ANDROID_HOME/ndk-bundle --android_abi=x86_64 --skip_submodule_sync --parallel --use_dnnlibrary
       displayName: Build and Test on Android Emulator