1沒寫節點文件，常見屬性
sys/class/power_supply
2沒寫注冊過程

batteryproperties Binder 服務的特色：

1. 能夠在java和C++之間傳遞對象（BatteryProperties對象）
2. 服務能夠主動給客戶端發送消息

一、電池電量從healthd傳到Java層的通信過程

C++:

system/core/healthd/healthd.cpp,
system/core/healthd/BatteryMonitor.cpp,
framework/native/services/batteryservice/include/batteryservice/IBatteryPropertiesListener.h
framework/native/services/batteryservice/IBatteryPropertiesListener.cpp
framework/native/services/batteryservice/include/batteryservice/IBatteryPropertiesRegistrar.h
system/core/healthd/BatteryPropertiesRegistor.cpp,
framework/native/services/batteryservice/include/batteryservice/IBatteryPropertiesRegistrar.h
framework/native/services/batteryservice/IBatteryPropertiesRegistrar.cpp
framework/base/core/java/android/os/IBatteryPropertiesListener.aidl

Java:

BatteryService, BatteryListener, IBatteryPropertiesListener.aidl, IBatteryPropertiesRegistrar.aidl,
BatteryState,BatteryStatesService(這兩個跟AMS相關，記錄更新應用耗電信息，暫未分析)

healthd進程除了讀取電池數據上報外，還有關機充電時繪制圖標的功能

先來張圖對Battery模塊有個整體認知

圖片.png

圖片.png

圖片.png

圖片.png

流程圖：

圖片.png

Battery框架的AIDL,java層和c層的交互

batteryproperties Binder服務

定義：
/frameworks/native/include/batteryservice/IBatteryPropertiesRegistrar.h
接口：
IBatteryPropertiesRegistrar

33class IBatteryPropertiesRegistrar : public IInterface {
34public:
35    DECLARE_META_INTERFACE(BatteryPropertiesRegistrar)
36
37    virtual void registerListener(const sp<IBatteryPropertiesListener>& listener) = 0;
38    virtual void unregisterListener(const sp<IBatteryPropertiesListener>& listener) = 0;
39    virtual status_t getProperty(int id, struct BatteryProperty *val) = 0;
40    virtual void scheduleUpdate() = 0;
41};

實現：
BnBatteryPropertiesRegistrar
/system/core/healthd/BatteryPropertiesRegistrar.cpp

sub 接口2：
IBatteryPoroertiesListener
C++語言定義的接口
/frameworks/native/include/batteryservice/IBatteryPropertiesListener.h

34class IBatteryPropertiesListener : public IInterface {
35public:
36    DECLARE_META_INTERFACE(BatteryPropertiesListener)
37
38    virtual void batteryPropertiesChanged(struct BatteryProperties props) = 0;
39};

java定義的接口（利用了AIDL）
/frameworks/base/core/java/android/os/IBatteryPropertiesListener.aidl

package android.os;
import android.os.BatteryProperties;

oneway interface IBatteryPropertiesListener {
    void batteryPropertiesChanged(in BatteryProperties props);
}

others :BatteryProperties類是如何在java和C++傳輸的

/frameworks/base/core/java/android/os/BatteryProperties.java 和 BatteryProperties.aidl
/frameworks/native/services/batteryservice/BatteryProperties.cpp
兩個保持一致，并且可序列化

參考資料：

（原創）android6.0系統Healthd深入分析
https://blog.csdn.net/u011311586/article/details/51082685
android 4.4 電池電量管理底層分析(C\C++層)
https://blog.csdn.net/daweibalang717/article/details/41446993

android 4.4 電池電量顯示分析（低電量提醒與電池圖標）Java 層
https://blog.csdn.net/daweibalang717/article/details/40615453
其他方面：
Android7.0BatteryStatsService[https://blog.csdn.net/gaugamela/article/details/52931949 ]
Android7.0BatteryService[https://blog.csdn.net/Gaugamela/article/details/52920222 ]
Android battery historian功耗分析之環境搭建[ http://www.lxweimin.com/p/5abd53abcc1e ]