JNI的架構和實現方式
阿新 • • 發佈：2019-01-24
在android中提供JNI的方式，讓Java程式可以呼叫C語言程式。Android中很多Java類都具有native介面，這些native介面就是由本地實現，然後註冊到系統中去的。
在Android中，主要的JNI程式碼在這裡：
frameworks/base/core/jni/
這個路徑中的內容將被編譯成庫libandroid_runtime.so，這就是一個普通的動態庫，被放置在目標系統的/system/lib目錄中。
除此之外，android還包含其他的JNI庫，例如：
媒體部分的JNI在目錄frameworks/base/media/jni/中，被編譯成libmedia_jni.so.
服務部分的JN在目錄frameworks/base/services/jni中，被編譯成libandroid_services.so
關於native顯式註冊可以看這裡 http://blog.csdn.net/thinkinwm/article/details/8637238
frameworks/base/services/jni/Android.mk 檔案
LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_SRC_FILES:= \ com_android_server_AlarmManagerService.cpp \ com_android_server_BatteryService.cpp \ com_android_server_input_InputApplicationHandle.cpp \ com_android_server_input_InputManagerService.cpp \ com_android_server_input_InputWindowHandle.cpp \ com_android_server_LightsService.cpp \ com_android_server_PowerManagerService.cpp \ com_android_server_SerialService.cpp \ com_android_server_SystemServer.cpp \ com_android_server_UsbDeviceManager.cpp \ com_android_server_UsbHostManager.cpp \ com_android_server_VibratorService.cpp \ com_android_server_location_GpsLocationProvider.cpp \ com_android_server_connectivity_Vpn.cpp \ onload.cpp LOCAL_C_INCLUDES += \ $(JNI_H_INCLUDE) \ frameworks/base/services \ frameworks/base/core/jni \ external/skia/include/core \ libcore/include \ libcore/include/libsuspend \ $(call include-path-for, libhardware)/hardware \ $(call include-path-for, libhardware_legacy)/hardware_legacy \ LOCAL_SHARED_LIBRARIES := \ libandroid_runtime \ libandroidfw \ libcutils \ libhardware \ libhardware_legacy \ libnativehelper \ libsystem_server \ libutils \ libui \ libinput \ libskia \ libgui \ libusbhost \ libsuspend ifeq ($(WITH_MALLOC_LEAK_CHECK),true) LOCAL_CFLAGS += -DMALLOC_LEAK_CHECK endif LOCAL_MODULE:= libandroid_servers include $(BUILD_SHARED_LIBRARY)
frameworks\base\core\jni\Android.mk 檔案
LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_CFLAGS += -DHAVE_CONFIG_H -DKHTML_NO_EXCEPTIONS -DGKWQ_NO_JAVA LOCAL_CFLAGS += -DNO_SUPPORT_JS_BINDING -DQT_NO_WHEELEVENT -DKHTML_NO_XBL LOCAL_CFLAGS += -U__APPLE__ ifeq ($(TARGET_ARCH), arm) LOCAL_CFLAGS += -DPACKED="__attribute__ ((packed))" else LOCAL_CFLAGS += -DPACKED="" endif ifeq ($(WITH_JIT),true) LOCAL_CFLAGS += -DWITH_JIT endif ifneq ($(USE_CUSTOM_RUNTIME_HEAP_MAX),) LOCAL_CFLAGS += -DCUSTOM_RUNTIME_HEAP_MAX=$(USE_CUSTOM_RUNTIME_HEAP_MAX) endif ifeq ($(USE_OPENGL_RENDERER),true) LOCAL_CFLAGS += -DUSE_OPENGL_RENDERER endif LOCAL_CFLAGS += -DGL_GLEXT_PROTOTYPES -DEGL_EGLEXT_PROTOTYPES LOCAL_SRC_FILES:= \ AndroidRuntime.cpp \ Time.cpp \ com_android_internal_content_NativeLibraryHelper.cpp \ com_google_android_gles_jni_EGLImpl.cpp \ com_google_android_gles_jni_GLImpl.cpp.arm \ android_app_NativeActivity.cpp \ android_opengl_GLES10.cpp \ android_opengl_GLES10Ext.cpp \ android_opengl_GLES11.cpp \ android_opengl_GLES11Ext.cpp \ android_opengl_GLES20.cpp \ android_database_CursorWindow.cpp \ android_database_SQLiteCommon.cpp \ android_database_SQLiteConnection.cpp \ android_database_SQLiteGlobal.cpp \ android_database_SQLiteDebug.cpp \ android_emoji_EmojiFactory.cpp \ android_view_Display.cpp \ android_view_DisplayEventReceiver.cpp \ android_view_Surface.cpp \ android_view_TextureView.cpp \ android_view_InputChannel.cpp \ android_view_InputDevice.cpp \ android_view_InputEventReceiver.cpp \ android_view_KeyEvent.cpp \ android_view_KeyCharacterMap.cpp \ android_view_HardwareRenderer.cpp \ android_view_GLES20DisplayList.cpp \ android_view_GLES20Canvas.cpp \ android_view_MotionEvent.cpp \ android_view_PointerIcon.cpp \ android_view_VelocityTracker.cpp \ android_text_AndroidCharacter.cpp \ android_text_AndroidBidi.cpp \ android_os_Debug.cpp \ android_os_FileUtils.cpp \ android_os_MemoryFile.cpp \ android_os_MessageQueue.cpp \ android_os_ParcelFileDescriptor.cpp \ android_os_Parcel.cpp \ android_os_StatFs.cpp \ android_os_SystemClock.cpp \ android_os_SystemProperties.cpp \ android_os_Trace.cpp \ android_os_UEventObserver.cpp \ android_net_LocalSocketImpl.cpp \ android_net_NetUtils.cpp \ android_net_TrafficStats.cpp \ android_net_wifi_Wifi.cpp \ android_nio_utils.cpp \ android_text_format_Time.cpp \ android_util_AssetManager.cpp \ android_util_Binder.cpp \ android_util_EventLog.cpp \ android_util_Log.cpp \ android_util_FloatMath.cpp \ android_util_Process.cpp \ android_util_StringBlock.cpp \ android_util_XmlBlock.cpp \ android/graphics/AutoDecodeCancel.cpp \ android/graphics/Bitmap.cpp \ android/graphics/BitmapFactory.cpp \ android/graphics/Camera.cpp \ android/graphics/Canvas.cpp \ android/graphics/ColorFilter.cpp \ android/graphics/DrawFilter.cpp \ android/graphics/CreateJavaOutputStreamAdaptor.cpp \ android/graphics/Graphics.cpp \ android/graphics/HarfbuzzSkia.cpp \ android/graphics/Interpolator.cpp \ android/graphics/LayerRasterizer.cpp \ android/graphics/MaskFilter.cpp \ android/graphics/Matrix.cpp \ android/graphics/Movie.cpp \ android/graphics/NinePatch.cpp \ android/graphics/NinePatchImpl.cpp \ android/graphics/NinePatchPeeker.cpp \ android/graphics/Paint.cpp \ android/graphics/Path.cpp \ android/graphics/PathMeasure.cpp \ android/graphics/PathEffect.cpp \ android_graphics_PixelFormat.cpp \ android/graphics/Picture.cpp \ android/graphics/PorterDuff.cpp \ android/graphics/BitmapRegionDecoder.cpp \ android/graphics/Rasterizer.cpp \ android/graphics/Region.cpp \ android/graphics/Shader.cpp \ android/graphics/SurfaceTexture.cpp \ android/graphics/TextLayout.cpp \ android/graphics/TextLayoutCache.cpp \ android/graphics/Typeface.cpp \ android/graphics/Utils.cpp \ android/graphics/Xfermode.cpp \ android/graphics/YuvToJpegEncoder.cpp \ android_media_AudioRecord.cpp \ android_media_AudioSystem.cpp \ android_media_AudioTrack.cpp \ android_media_JetPlayer.cpp \ android_media_ToneGenerator.cpp \ android_hardware_Camera.cpp \ android_hardware_SensorManager.cpp \ android_hardware_SerialPort.cpp \ android_hardware_UsbDevice.cpp \ android_hardware_UsbDeviceConnection.cpp \ android_hardware_UsbRequest.cpp \ android_debug_JNITest.cpp \ android_util_FileObserver.cpp \ android/opengl/poly_clip.cpp.arm \ android/opengl/util.cpp.arm \ android_bluetooth_HeadsetBase.cpp \ android_bluetooth_common.cpp \ android_bluetooth_BluetoothAudioGateway.cpp \ android_bluetooth_BluetoothSocket.cpp \ android_bluetooth_c.c \ android_server_BluetoothService.cpp \ android_server_BluetoothEventLoop.cpp \ android_server_BluetoothA2dpService.cpp \ android_server_NetworkManagementSocketTagger.cpp \ android_server_Watchdog.cpp \ android_ddm_DdmHandleNativeHeap.cpp \ com_android_internal_os_ZygoteInit.cpp \ android_backup_BackupDataInput.cpp \ android_backup_BackupDataOutput.cpp \ android_backup_FileBackupHelperBase.cpp \ android_backup_BackupHelperDispatcher.cpp \ android_app_backup_FullBackup.cpp \ android_content_res_ObbScanner.cpp \ android_content_res_Configuration.cpp \ android_animation_PropertyValuesHolder.cpp LOCAL_C_INCLUDES += \ $(JNI_H_INCLUDE) \ $(LOCAL_PATH)/android/graphics \ $(LOCAL_PATH)/../../libs/hwui \ $(LOCAL_PATH)/../../../native/opengl/libs \ $(call include-path-for, bluedroid) \ $(call include-path-for, libhardware)/hardware \ $(call include-path-for, libhardware_legacy)/hardware_legacy \ $(TOP)/frameworks/av/include \ external/skia/include/core \ external/skia/include/effects \ external/skia/include/images \ external/skia/src/ports \ external/skia/include/utils \ external/sqlite/dist \ external/sqlite/android \ external/expat/lib \ external/openssl/include \ external/tremor/Tremor \ external/icu4c/i18n \ external/icu4c/common \ external/jpeg \ external/harfbuzz/contrib \ external/harfbuzz/src \ external/zlib \ frameworks/opt/emoji \ libcore/include LOCAL_SHARED_LIBRARIES := \ libandroidfw \ libexpat \ libnativehelper \ libcutils \ libutils \ libbinder \ libnetutils \ libui \ libgui \ libcamera_client \ libskia \ libsqlite \ libdvm \ libEGL \ libGLESv1_CM \ libGLESv2 \ libETC1 \ libhardware \ libhardware_legacy \ libsonivox \ libcrypto \ libssl \ libicuuc \ libicui18n \ libmedia \ libmedia_native \ libwpa_client \ libjpeg \ libusbhost \ libharfbuzz \ libz ifeq ($(USE_OPENGL_RENDERER),true) LOCAL_SHARED_LIBRARIES += libhwui endif ifeq ($(BOARD_HAVE_BLUETOOTH),true) LOCAL_C_INCLUDES += \ external/dbus \ system/bluetooth/bluez-clean-headers LOCAL_CFLAGS += -DHAVE_BLUETOOTH LOCAL_SHARED_LIBRARIES += libbluedroid libdbus endif LOCAL_SHARED_LIBRARIES += \ libdl # we need to access the private Bionic header # <bionic_tls.h> in com_google_android_gles_jni_GLImpl.cpp LOCAL_CFLAGS += -I$(LOCAL_PATH)/../../../../bionic/libc/private LOCAL_LDLIBS += -lpthread -ldl ifeq ($(WITH_MALLOC_LEAK_CHECK),true) LOCAL_CFLAGS += -DMALLOC_LEAK_CHECK endif LOCAL_MODULE:= libandroid_runtime include $(BUILD_SHARED_LIBRARY) include $(call all-makefiles-under,$(LOCAL_PATH))