android binder

android native（C++）层的service 一般都会用到binder，通过binder的机制对外提供接口，如果我们需要实现一个native 层的service，那么要怎么做呢？

这个基本上是一个固定的套路，所以我们需要先了解一下android 提供的binder （框架？）的关系。XXXService就是要基于binder通信的类。

    例如要实现一个TestService

    1、ITestService.h 

      

#ifndef ANDROID_HXIONG_ITEST_H#define ANDROID_HXIONG_ITEST_H#include <stdint.h>#include <sys/types.h>#include <utils/Errors.h>#include <utils/RefBase.h>#include <binder/IInterface.h>namespace android {class ITestService : public IInterface{public:    DECLARE_META_INTERFACE(ITestService);    virtual status_t test(int api) = 0;};// ----------------------------------------------------------------------------class BnTestService : public BnInterface<ITestService>{public:    virtual status_t    onTransact( uint32_t code,                                    const Parcel& data,                                    Parcel* reply,                                    uint32_t flags = 0);};// ----------------------------------------------------------------------------}; // namespace android#endif 

     2、ITestService.cpp

#include <binder/Parcel.h>#include <binder/IInterface.h>#include <ITestService.h>namespace android {// ----------------------------------------------------------------------------enum {    TEST = IBinder::FIRST_CALL_TRANSACTION,}class BpTestService : public BpInterface<ITestService>{    BpTestService()    {    }    virtual ~BpTestService();        virtual status_t test(int api) {        Parcel data, reply;        data.writeInterfaceToken(ITestService::getInterfaceDescriptor());        data.writeInt32(api);        remote()->transact(TEST, data, &reply);        result = reply.readInt32();        return result;    }};IMPLEMENT_META_INTERFACE(TestService, "com.hxiong.ITestService");status_t BnTestService::onTransact(    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags){    switch(code) {        case TEST: {            CHECK_INTERFACE(ITestService, data, reply);            int api = data.readInt32();            int result=test(api);    //这里会调用到TestService 的test函数            reply->writeInt32(result);            return NO_ERROR;        }    }    return BBinder::onTransact(code, data, reply, flags);}

     3、TestService.h

#ifndef ANDROID_HXIONFG_TEST_H#define ANDROID_HXIONFG_TEST_H#include <ITestService.h>namespace android {class TestService : public BnTestService{public:      TestService();    virtual ~TestService();       virtual status_t test(int api);};}#endif

4、TestService.cpp

#include <TestService.h>namespace android {TestService::TestService(){}TestService::~TestService() {}status_t TestService::test(int api){   return 0;}}