/******************************************************************************* *                  I.MX6 Android frameworks services 文件架构 * 说明： *     这部分内容后续可能需要多给一点注意力了，因为这部分在做系统移植的时候经常 * 需要通过这部分来进行调试。 *                                           2016-3-19 深圳 南山平山村 曾剑锋 ******************************************************************************/一、cat frameworks/base/services/jni/Android.mk    # 获取当前路径    LOCAL_PATH:= $(call my-dir)    # 清理变量，但是不会清理LOCAL_PATH变量的值    include $(CLEAR_VARS)    # 指定jni cpp文件    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_power_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                            -----------------------------+                                                                           |    # 指定jni cpp依赖的头文件                                              |    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 \                   |        $(call include-path-for, libhardware_legacy)/hardware_legacy \     |                                                                           |    # 指定依赖的库文件                                                     |    LOCAL_SHARED_LIBRARIES := \                                            |        libandroid_runtime \                                               |        libandroidfw \                                                     |        libcutils \                                                        |        libhardware \                                                      |        libhardware_legacy \                                               |        libnativehelper \                                                  |        libsystem_server \                                                 |        libutils \                                                         |        libui \                                                            |        libinput \                                                         |        libskia \                                                          |        libgui \                                                           |        libusbhost \                                                       |        libsuspend                                                         |                                                                           |    ifeq ($(WITH_MALLOC_LEAK_CHECK),true)                                  |        LOCAL_CFLAGS += -DMALLOC_LEAK_CHECK                                |    endif                                                                  |                                                                           |    # 生成的模块的名字                                                     |    LOCAL_MODULE:= libandroid_servers                                      |                                                                           |    # 这里相当于开始编译                                                   |    include $(BUILD_SHARED_LIBRARY)                                        |                                                                           |二、cat frameworks/base/services/jni/onload.cpp             <--------------+    /*     * Copyright (C) 2009 The Android Open Source Project     *     * Licensed under the Apache License, Version 2.0 (the "License");     * you may not use this file except in compliance with the License.     * You may obtain a copy of the License at     *     *      http://www.apache.org/licenses/LICENSE-2.0     *     * Unless required by applicable law or agreed to in writing, software     * distributed under the License is distributed on an "AS IS" BASIS,     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.     * See the License for the specific language governing permissions and     * limitations under the License.     */    #include "JNIHelp.h"    #include "jni.h"    #include "utils/Log.h"    #include "utils/misc.h"    // 声明接下来的需要用到android命名空间中的jni函数    namespace android {    int register_android_server_AlarmManagerService(JNIEnv* env);    int register_android_server_BatteryService(JNIEnv* env);    int register_android_server_InputApplicationHandle(JNIEnv* env);    int register_android_server_InputWindowHandle(JNIEnv* env);    int register_android_server_InputManager(JNIEnv* env);    int register_android_server_LightsService(JNIEnv* env);    int register_android_server_PowerManagerService(JNIEnv* env);    int register_android_server_SerialService(JNIEnv* env);    int register_android_server_UsbDeviceManager(JNIEnv* env);    int register_android_server_UsbHostManager(JNIEnv* env);    int register_android_server_VibratorService(JNIEnv* env);    int register_android_server_SystemServer(JNIEnv* env);    int register_android_server_location_GpsLocationProvider(JNIEnv* env);    int register_android_server_connectivity_Vpn(JNIEnv* env);    };    // 使用命名空间    using namespace android;    // C语言JNI加载函数，用于调用前面的android命名空间总的函数，这些函数    // 主要是对JNI进行注册。    extern "C" jint JNI_OnLoad(JavaVM* vm, void* reserved)    {        JNIEnv* env = NULL;        jint result = -1;        if (vm->GetEnv((void**) &env, JNI_VERSION_1_4) != JNI_OK) {            ALOGE("GetEnv failed!");            return result;        }        ALOG_ASSERT(env, "Could not retrieve the env!");        register_android_server_PowerManagerService(env);   ---------------+        register_android_server_SerialService(env);                        |        register_android_server_InputApplicationHandle(env);               |        register_android_server_InputWindowHandle(env);                    |        register_android_server_InputManager(env);                         |        register_android_server_LightsService(env);                        |        register_android_server_AlarmManagerService(env);                  |        register_android_server_BatteryService(env);                       |        register_android_server_UsbDeviceManager(env);                     |        register_android_server_UsbHostManager(env);                       |        register_android_server_VibratorService(env);                      |        register_android_server_SystemServer(env);                         |        register_android_server_location_GpsLocationProvider(env);         |        register_android_server_connectivity_Vpn(env);                     |                                                 +-------------------------+        return JNI_VERSION_1_4;                  |       间接加载    }                                            |                                                 v三、cat frameworks/base/services/jni/com_android_server_BatteryService.cpp    ......    namespace android {    #define POWER_SUPPLY_PATH "/sys/class/power_supply"    static void android_server_BatteryService_update(JNIEnv* env, jobject obj)    {        setBooleanField(env, obj, gPaths.acOnlinePath, gFieldIds.mAcOnline);        setBooleanField(env, obj, gPaths.usbOnlinePath, gFieldIds.mUsbOnline);        setBooleanField(env, obj, gPaths.wirelessOnlinePath, gFieldIds.mWirelessOnline);        setBooleanField(env, obj, gPaths.batteryPresentPath, gFieldIds.mBatteryPresent);        setIntField(env, obj, gPaths.batteryCapacityPath, gFieldIds.mBatteryLevel);        setVoltageField(env, obj, gPaths.batteryVoltagePath, gFieldIds.mBatteryVoltage);        setIntField(env, obj, gPaths.batteryTemperaturePath, gFieldIds.mBatteryTemperature);        char prop[5];        // always report AC plug-in and capacity 100% if emulated.battery is set to 1        property_get("sys.emulated.battery", prop, "0");        if (!strcmp(prop, "1")){            env->SetBooleanField(obj, gFieldIds.mAcOnline, true);            env->SetIntField(obj, gFieldIds.mBatteryLevel, 100);        }        const int SIZE = 128;        char buf[SIZE];        if (readFromFile(gPaths.batteryStatusPath, buf, SIZE) > 0)            env->SetIntField(obj, gFieldIds.mBatteryStatus, getBatteryStatus(buf));        else            env->SetIntField(obj, gFieldIds.mBatteryStatus,                             gConstants.statusUnknown);        if (readFromFile(gPaths.batteryHealthPath, buf, SIZE) > 0)            env->SetIntField(obj, gFieldIds.mBatteryHealth, getBatteryHealth(buf));        if (readFromFile(gPaths.batteryTechnologyPath, buf, SIZE) > 0)            env->SetObjectField(obj, gFieldIds.mBatteryTechnology, env->NewStringUTF(buf));    }    static JNINativeMethod sMethods[] = {         /* name, signature, funcPtr */        {
    "native_update", "()V", (void*)android_server_BatteryService_update},    };    int register_android_server_BatteryService(JNIEnv* env)    {        ......        return jniRegisterNativeMethods(env, "com/android/server/BatteryService", sMethods, NELEM(sMethods));    }                                                       |                                                            |    } /* namespace android */                               |                                                            V四、cat frameworks/base/services/java/com/android/server/BatteryService.java    ......    public final class BatteryService extends Binder {        ......        private native void native_update();        ......        private void updateLocked() {            if (!mUpdatesStopped) {                // Update the values of mAcOnline, et. all.                native_update();                // Process the new values.                processValuesLocked();            }        }        ......    }