原址
前面几篇博客中系统地介绍了本地服务的注册、检索以及使用过程。这篇博客我们将完成一个属于自己的本地服务:AllenService。
由前面的学习知道，要完成一个自己的本地服务，需要有IAllenService接口、BnAllenService服务Stub、AllenService、BpAllenService。UML图如下：
各文件的路径如下：
-
frameworks/base/include/allen/IAllenService.h,AllenService.h
-
frameworks/base/libs/allen/IAllenService.cpp,AllenService.cpp
-
frameworks/base/cmds/allen/main_allenclient.cpp,main_allenservice.cpp
1.IAllenService.h文件
该头文件中包含了接口描述符以及枚举类。另外，与Android中的服务接口文件类似，这里将BnAllenService的定义也放在该头文件中，所以该头文件的代码如下：
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| #ifndef FRAMEWORKS_BASE_INCLUDE_IALLENSERVICE_H_
#define FRAMEWORKS_BASE_INCLUDE_IALLEN_SERVICE_H_
#include <utils/Errors.h>
#include <utils/KeyedVector.h>
#include <utils/RefBase.h>
#include <utils/String8.h>
#include <binder/IInterface.h>
#include <binder/Parcel.h>
#include <AllenService.h>
namespace android{
#define MATH_ERROR int32(-1)
#define ALLEN_DESCRIPTOR "android.allen.IAllenService"
enum{
ALLEN_PRINT=IBinder::FIRST_CALL_TRANSACTION,
ALLEN_ADD,
ALLEN_SUB
};
class IAllenService:public IInterface
{
public:
//宏定义
DECLARE_META_INTERFACE(AllenService);
virtual status_t print(const char*str)=0;
virtual int32 add(int32 a,int32 b)=0;
virtual int32 sub(int32 a,int32 b)=0;
};
class BnAllenService:public BnInterface<IAllenService>
{
public:
virtual status_t onTransact(uint32_t code,
const Parcel& data,
Parcel*reply,
uint32_t flags=0);
};
};//namespace android
#endif
|
- AllenService.h
AllenService头文件的代码如下：
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| #ifndef FRAMEWORKS_BASE_INCLUDE_ALLEN_ALLENSERVICE_H_
#define FRAMEWORKS_BASE_INCLUDE_ALLEN_ALLENSERVICE_H_
#include <utils/Log.h>
#include <utils/threads.h>
#include <utils/List.h>
#include <utils/Errors.h>
#include <utils/KeyedVector.h>
#include <utils/String8.h>
#include <utils/Vector.h>
#include <IAllenService.h>
namespace android{
class AllenService:public BnAllenService{
public:
static void instantiate();
virtual status_t print(const char*str);
virtual int32 add(int32 a,int32 b);
virtual int32 sub(int32 a,int32 b);
virtual status_t onTransact(
uint32_t code,
const Parcel& data,
Parcel* reply,
uint32_t flags);
private:
AllenService();
virtual ~AllenService();
};
}; //namespace android
#endif
|
- IAllenService.cpp
该文件中不仅有IAllenService中宏接口的实现，还有BnAllenService的实现，另外，还有BpAllenService的定义以及实现。
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| #include <stdint.h>
#include <sys/types.h>
#include <binder/Parcel.h>
#include <binder/IMemory.h>
#include <allen/IAllenService.h>
#include <allen/AllenService.h>
#include <utils/Errors.h>
namespace android{
class BpAllenService: public BpInterface<IAllenService>
{
public:
BpAllenService(const sp<IBinder>& impl):BpInterface<IAllenService>(impl)
{
}
virtual status_t print(const char*str)
{
Parcel data,reply;
data.writeInterfaceToken(IAllenService::getInterfaceDescriptor());
data.writeCString(str);
status_t status=remote()->transact(ALLEN_PRINT,data,&reply);
if(status!=NO_ERROR){
LOGE("print str error:%s",strerror(-status));
}else{
status=reply.readInt32();
}
return status;
}
virtual int32 add(int32 a,int32 b)
{
Parcel data,reply;
data.writeInterfaceToken(IAllenService::getInterfaceDescriptor());
data.writeInt32(a);
data.writeInt32(b);
status_t status=remote()->transact(ALLEN_ADD,data,&reply);
return reply.readInt32();
}
virtual int32 sub(int32 a,int32 b)
{
Parcel data,reply;
data.writeInterfaceToken(IAllenService::getInterfaceDescriptor());
data.writeInt32(a);
data.writeInt32(b);
status_t status=remote()->transact(ALLEN_SUB,data,&reply);
return reply.readInt32();
}
};
//宏实现
IMPLEMENT_META_INTERFACE(AllenService,ALLEN_DESCRIPTOR)
status BnAllenService::onTransact(uint32_t code,const Parcel& data,Parcel* reply,uint32_t flags)
{
switch(code){
case ALLEN_PRINT:{
CHECK_INTERFACE(IAllenService,data,reply);
const char*str=data.readCString();
reply->writeInt32(print(str));
return NO_ERROR;
}break;
case ALLEN_ADD:{
CHECK_INTERFAC(IAllenService,data,reply);
int32 a=data.readInt32();
int32 b=data.readInt32();
reply->writeInt32(this->add(a,b));
return NO_ERROR;
}break;
case ALLEN_SUB:{
CHECK_INTERFACE(IAllenService,data,reply);
int32 a=data.readInt32();
int32 b=data.readInt32();
reply->writeInt32(this->sub(a,b));
return NO_ERROR;
}break;
default:
return BBinder::onTransact(code,data,reply,flags);
}
}
};
|
4.AllenService.cpp
该文件实现服务接口。代码如下：
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| namespace android{
void AllenService::instantiate(){
defaultServiceManager()->addService(
String16(ALLEN_DESCRIPTOR),new AllenService());
}
status_t AllenService::print(const char*str){
LOGI("%s\n",str);
printf("%s\n",str);
return NO_ERROR;
}
int32 AllenService::add(int32 a,int32 b){
LOGI("a=%d,b=%d",a,b);
return a+b;
}
int32 AllenService::sub(int32 a,int32 b){
LOGI("a=%d,b=%d",a,b);
return a-b;
}
};
|
5.main_allenservice.cpp
创建好AllenService后，如果想要运行它，就需要有服务客户端和Service Server进程，服务代理运行在服务客户端中，服务运行在Service Server进程中。如下图所示：
main_allenservice.cpp的代码如下：
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| int main(int argc,char** argv)
{
sp<ProcessState>proc(ProcessState::self());
sp<IServiceManager>sm=defaultServiceManager();
LOGI("ServiceManager: %p",sm.get());
AllenService::instantiate();
ProcessState::self()->startThreadPool();
ProcessState::self()->joinThreadPool();
return 0;
}
|
6.main_allenclient.cpp
main_allenclient.cpp的代码如下：
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| int main(int argc,char *argv[])
{
LOGI("allenservice cleint is now starting");
sp<IServiceManager>sm=defaultServiceManager();
sp<IBinder>binder;
sp<IAllenService>allenService;
do{
binder=sm->getService(String16(ALLEN_DESCRIPTOR));
if(binder!=0)
{
break;
}
LOGI("AllenService is not working,try again...");
usleep(500000);
}while(true);
allenService=interface_cast<IAllenService>(binder);
allenService->print("Hello world!\nI'm Allen and I'm coning.\n");
allenService->add(3,6);
allenService->sub(1,1);
return 0;
}
|
7.编译AllenService系统服务
若想编译AllenService服务代码，需要将AllenService的源码包含进Android平台源码中，再进行整体编译。首先保证头文件在/frameworks/base/include/allen下，源代码文件在/frameworks/base/libs/allen下，而后编写Android.mk文件，编写完成后，将其放到源代码目录中，以便将源代码与Android平台代码一起编译。
Android.mk文件内容如下：
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| LOCAL_PATH:=$(call my-dir)
include &(CLEAR_VARS)
LOCAL_SRC_FILES:= \
IAllenService.cpp \
AllenService.cpp
LOCAL_SHARED_LIBRARES :=\
libcutils \
libutils \
libbinder \
LOCAL_PRELINK_MODULE := false
LOCAL_MODULE :=liballen
include $(BUILD_SHARED_LIBRARY)
|
接着，编写运行main_allenservice.cpp和main_allenclient.cpp的Android.mk文件，内容如下：
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| LOCAL_PATH:= $(call my-dir)
include $(CLEAR_VARS)
LOCAL_SRC_FILES:= \
main_allenserver.cpp
LOCAL_SHARED_LIBRARIES := \
libutils \
libbinder \
liballen
base := $(LOCAL_APTH)/../..
LOCAL_MODULE:= allenservice
incldue $(BUILD_EXECUTABLE)
include $(CLEAR_VARS)
LOCAL_SRC_FILES:= \
main_allenclient.cpp
LOCAL_SHARED_LIBRARIES := \
libutils \
libbinder \
liballen
base :=$(LOCAL_PATH)/../..
LOCAL_MODULE:=allenclient
include $(BUILD_EXECUTABLE)
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Posted by AllenWang Mar 1st, 2016 11:59 am android_deep_analysis
