Android4.4添加系统服务(aidl接口服务)

1. 编译好的Android4.4源码 用于获取系统服务CPU的Core数量。
2. AndroidStudio工具 用于编写apk调用系统接口

1. 添加aidl接口 frameworks/base/core/java/android/app/ICpuInfoManager.aidl

   package android.app;  interface ICpuInfoManager { 
                  int getCpuCore(); } 

2. 实现增加系统服务aidl文件的接口 frameworks/base/services/java/com/android/server/CpuInfoManagerService.java

   package com.android.server;import android.app.ICpuInfoManager; import android.content.Context; import android.util.Slog; public class CpuInfoManagerService extends ICpuInfoManager.Stub {        
              private Context mContext; public CpuInfoManagerService(Context context){        
              mContext = context; Slog.d("CPUINFO","Construct"); } @Override public int getCpuCore(){        
              return 4; } }  

3. 增加系统服务Manager frameworks/base/core/java/android/app/CpuInfoManager.java

   package android.app; import android.content.Context; import android.os.RemoteException; import android.util.Slog; public class CpuInfoManager { 
               Context mContext; ICpuInfoManager mService; public CpuInfoManager(Context context,ICpuInfoManager service){ 
               mContext = context; mService = service; } public int getCpuCore(){ 
               if(mService != null){ 
               try{ 
               return mService.getCpuCore(); }catch(RemoteException e){ 
               Slog.e("CPUINFO","RemoteException " + e); } } return -1; } } 

4. 将aidl文件添加至Android.mk参与编译 frameworks/base/Android.mk

   LOCAL_SRC_FILES += \
       core/java/android/app/ICpuInfoManager.aidl \
   

5. 添加Context中的Service常量 frameworks/base/core/java/android/content/Context.java

       /** * 用于Service的注册、SystemServer中的开机启动以及上层应用的使用 */
       public static final String CPU_INFO_SERVICE = "cpuinfo";
   

6. 将实现的服务注册到系统中去 frameworks/base/core/java/android/app/ContextImpl.java

           registerService(CONSUMER_IR_SERVICE, new ServiceFetcher() { 
             
               public Object createService(ContextImpl ctx) { 
             
                   return new ConsumerIrManager(ctx);
               }});
   
           // add register cpuinfo service
           registerService(CPU_INFO_SERVICE, new ServiceFetcher() { 
             
               public Object createService(ContextImpl ctx) { 
             
                   IBinder iBinder = ServiceManager.getService(Context.CPU_INFO_SERVICE);
                   return new CpuInfoManager(ctx, ICpuInfoManager.Stub.asInterface(iBinder));
               }});
   

7. 将注册的服务设置成开机启动 frameworks/base/services/java/com/android/server/SystemServer.java

           try { 
             
               display.systemReady(safeMode, onlyCore);
           } catch (Throwable e) { 
             
               reportWtf("making Display Manager Service ready", e);
           }
           
           // add cpuinfo service
           try{ 
             
               ServiceManager.addService(Context.CPU_INFO_SERVICE, new CpuInfoManagerService(context));
           } catch(Throwable e){ 
             
               Slog.e("CPUINFO","Failed to start CpuInfoManagerService " + e);
           }
   

8. 更新api接口并且编译源码

          make  update-api
          make -j32
   

   之后更新系统。

1. AndroidStudio中引入AOSP的jar包 此处导入out/target/common/obj/JAVA_LIBRARIES/framework_intermediates/classes.jar即可。

2. 编写app测试 调用部分代码：

          CpuInfoManager cm = (CpuInfoManager) getSystemService("cpuinfo"); // cpuinfo即Context.CPU_INFO_SERVICE, 不知道为什么，AndroidStudio引入frameworkjar包后，调不到。
          Log.d("CPUINFO", "getcpuinfo: " + cm.getCpuCore());
   

1. 查看服务是否启动 串口下输入

   service list | grep cpuinfo
   

   出现以下信息即为添加系统调用服务成功：

   53      cpuinfo: [android.app.ICpuInfoManager]
   

2. logcat查看app是否调用成功 串口下输入

   logcat -vthreadtime -s CPUINFO 
   

   出现以下打印(cpu core is 4)即为app调用成功：

   --------- beginning of /dev/log/system
   --------- beginning of /dev/log/main
   01-01 08:00:04.433  1930  1930 D CPUINFO : Construct
   05-18 15:03:26.770  4993  4993 D CPUINFO : cpu core is 4
   

Android AOSP 添加系统服务【aidl接口服务】Java层