Add no_samples_build option to Android SDK build

CMakeLists.txt

@@ -964,7 +964,7 @@ if(BUILD_opencv_apps)
 endif()
 
 # examples
-if(BUILD_EXAMPLES OR BUILD_ANDROID_EXAMPLES OR INSTALL_PYTHON_EXAMPLES OR INSTALL_C_EXAMPLES)
+if(BUILD_EXAMPLES OR BUILD_ANDROID_EXAMPLES OR INSTALL_ANDROID_EXAMPLES OR INSTALL_PYTHON_EXAMPLES OR INSTALL_C_EXAMPLES)
   add_subdirectory(samples)
 endif()
 
@@ -1199,7 +1199,7 @@ ocv_build_features_string(apps_status
   IF BUILD_EXAMPLES THEN "examples"
   IF BUILD_opencv_apps THEN "apps"
   IF BUILD_ANDROID_SERVICE THEN "android_service"
-  IF BUILD_ANDROID_EXAMPLES AND CAN_BUILD_ANDROID_PROJECTS THEN "android_examples"
+  IF (BUILD_ANDROID_EXAMPLES OR INSTALL_ANDROID_EXAMPLES) AND CAN_BUILD_ANDROID_PROJECTS THEN "android_examples"
   ELSE "-")
 status("    Applications:" "${apps_status}")
 ocv_build_features_string(docs_status

cmake/android/android_gradle_projects.cmake

@@ -105,17 +105,29 @@ macro(add_android_project target path)
 include ':${__dir}'
 ")
 
-  # build apk
-  set(APK_FILE "${ANDROID_BUILD_BASE_DIR}/${__dir}/build/outputs/apk/release/${__dir}-${ANDROID_ABI}-release-unsigned.apk")
-  ocv_update(OPENCV_GRADLE_VERBOSE_OPTIONS "-i")
-  add_custom_command(
-      OUTPUT "${APK_FILE}" "${OPENCV_DEPHELPER}/android_sample_${__dir}"
-      COMMAND ./gradlew ${OPENCV_GRADLE_VERBOSE_OPTIONS} "${__dir}:assemble"
-      COMMAND ${CMAKE_COMMAND} -E touch "${OPENCV_DEPHELPER}/android_sample_${__dir}"
-      WORKING_DIRECTORY "${ANDROID_BUILD_BASE_DIR}"
-      DEPENDS ${depends} opencv_java_android
-      COMMENT "Building OpenCV Android sample project: ${__dir}"
-  )
+  if (BUILD_ANDROID_EXAMPLES)
+    # build apk
+    set(APK_FILE "${ANDROID_BUILD_BASE_DIR}/${__dir}/build/outputs/apk/release/${__dir}-${ANDROID_ABI}-release-unsigned.apk")
+    ocv_update(OPENCV_GRADLE_VERBOSE_OPTIONS "-i")
+    add_custom_command(
+        OUTPUT "${APK_FILE}" "${OPENCV_DEPHELPER}/android_sample_${__dir}"
+        COMMAND ./gradlew ${OPENCV_GRADLE_VERBOSE_OPTIONS} "${__dir}:assemble"
+        COMMAND ${CMAKE_COMMAND} -E touch "${OPENCV_DEPHELPER}/android_sample_${__dir}"
+        WORKING_DIRECTORY "${ANDROID_BUILD_BASE_DIR}"
+        DEPENDS ${depends} opencv_java_android
+        COMMENT "Building OpenCV Android sample project: ${__dir}"
+    )
+  else()  # install only
+    # copy samples
+    add_custom_command(
+        OUTPUT "${OPENCV_DEPHELPER}/android_sample_${__dir}"
+        COMMAND ${CMAKE_COMMAND} -E touch "${OPENCV_DEPHELPER}/android_sample_${__dir}"
+        WORKING_DIRECTORY "${ANDROID_BUILD_BASE_DIR}"
+        DEPENDS ${depends} opencv_java_android
+        COMMENT "Copying OpenCV Android sample project: ${__dir}"
+    )
+  endif()
+
   file(REMOVE "${OPENCV_DEPHELPER}/android_sample_${__dir}")  # force rebuild after CMake run
 
   add_custom_target(android_sample_${__dir} ALL DEPENDS "${OPENCV_DEPHELPER}/android_sample_${__dir}" SOURCES "${ANDROID_SAMPLE_MANIFEST_PATH}")

platforms/android/build_sdk.py

@@ -151,6 +151,7 @@ def __init__(self, workdir, opencvdir, config):
         self.ninja_path = self.get_ninja()
         self.debug = True if config.debug else False
         self.debug_info = True if config.debug_info else False
+        self.no_samples_build = True if config.no_samples_build else False
 
     def get_cmake(self):
         if not self.config.use_android_buildtools and check_executable(['cmake', '--version']):
@@ -217,7 +218,7 @@ def build_library(self, abi, do_install):
             BUILD_TESTS="OFF",
             BUILD_PERF_TESTS="OFF",
             BUILD_DOCS="OFF",
-            BUILD_ANDROID_EXAMPLES="ON",
+            BUILD_ANDROID_EXAMPLES=("OFF" if self.no_samples_build else "ON"),
             INSTALL_ANDROID_EXAMPLES="ON",
         )
         if self.ninja_path != 'ninja':
@@ -243,8 +244,11 @@ def build_library(self, abi, do_install):
         execute(cmd)
         # full parallelism for C++ compilation tasks
         execute([self.ninja_path, "opencv_modules"])
-        # limit parallelism for Gradle steps (avoid huge memory consumption)
-        execute([self.ninja_path, '-j3', "install" if (self.debug_info or self.debug) else "install/strip"])
+        # limit parallelism for building samples (avoid huge memory consumption)
+        if self.no_samples_build:
+            execute([self.ninja_path, "install" if (self.debug_info or self.debug) else "install/strip"])
+        else:
+            execute([self.ninja_path, "-j1" if (self.debug_info or self.debug) else "-j3", "install" if (self.debug_info or self.debug) else "install/strip"])
 
     def build_javadoc(self):
         classpaths = []
@@ -323,6 +327,7 @@ def gather_results(self):
     parser.add_argument('--force_opencv_toolchain', action="store_true", help="Do not use toolchain from Android NDK")
     parser.add_argument('--debug', action="store_true", help="Build 'Debug' binaries (CMAKE_BUILD_TYPE=Debug)")
     parser.add_argument('--debug_info', action="store_true", help="Build with debug information (useful for Release mode: BUILD_WITH_DEBUG_INFO=ON)")
+    parser.add_argument('--no_samples_build', action="store_true", help="Do not build samples (speeds up build)")
     args = parser.parse_args()
 
     log.basicConfig(format='%(message)s', level=log.DEBUG)

platforms/android/gradle-wrapper/gradle.properties

@@ -9,7 +9,7 @@
 
 # Specifies the JVM arguments used for the daemon process.
 # The setting is particularly useful for tweaking memory settings.
-org.gradle.jvmargs=-Xmx1536m
+org.gradle.jvmargs=-Xmx2g
 
 # When configured, Gradle will run in incubating parallel mode.
 # This option should only be used with decoupled projects. More details, visit

samples/CMakeLists.txt

@@ -38,7 +38,7 @@ endif()
 if(UNIX AND NOT ANDROID AND (HAVE_VA OR HAVE_VA_INTEL))
   add_subdirectory(va_intel)
 endif()
-if(ANDROID AND BUILD_ANDROID_EXAMPLES)
+if(ANDROID AND (BUILD_ANDROID_EXAMPLES OR INSTALL_ANDROID_EXAMPLES))
   add_subdirectory(android)
 endif()
 if(INSTALL_PYTHON_EXAMPLES)