Binder Bp 在不同进程中被使用

场景：

1）IMediaPlayer.cpp

Bn -> Bp

sp<IGraphicBufferProducer> bufferProducer =

interface_cast<IGraphicBufferProducer>(data.readStrongBinder());

reply->writeInt32(setVideoSurfaceTexture(bufferProducer));

在mediaplayerservice中使用
     sp<IGraphicBufferProducer>& bufferProducer 该Bp 与Bn 交互

2） 将mediaplayerservice进程中该Bp对象传递给另外一个进程中使用

virtual status_t connect(const sp<IGraphicBufferProducer> &bufferProduce,    sp<IRemoteDisplayClient> &sinkClient)

{

Parcel data, reply;

data.writeInterfaceToken(IRemoteDisplay::getInterfaceDescriptor());

data.writeStrongBinder(IInterface::asBinder(bufferProduce));

data.writeStrongBinder(IInterface::asBinder(sinkClient));

remote()->transact(CONNECT, data, &reply);

return reply.readInt32();

}

status_t BnRemoteDisplay::onTransact(..........）{.........

case CONNECT:{

CHECK_INTERFACE(IRemoteDisplay, data, reply);

sp<IGraphicBufferProducer> bufferproducer = IGraphicBufferProducer::asInterface(data.readStrongBinder());  //从mediaplayerservice进程中获取到的Bp对象在这边也可以被使用

sp<IRemoteDisplayClient> clientsink =  interface_cast<IRemoteDisplayClient>(data.readStrongBinder());

reply->writeInt32(connect(bufferproducer,clientsink));

return NO_ERROR;

}

3） 一个BnXX  可以被多个类继承，然后在不同接口处 得到的Bp

return interface_cast<IRemoteDisplay>(reply.readStrongBinder());

自身能够区分出来对应是哪个类的Bn

<IRemoteDisplay> 与RemoteDisplay 不是一一对应， IRemoteDisplay 可能对应多个类