Binder实用指南 - 实战篇

Posted 2022-11-28 火山石

本章的内容主要说明如何在JavaFramework层和Native层自定义Client-Server组件，并且使用Binder进行通信。

一、Native Binder

源码目录结构:

alps/frameworks/native/cmds/NativeBinderDemo/

1 2 3 4 5 6

|-NativeBinderDemo |---ClientDemo.cpp: 客户端程序 |---ServerDemo.cpp：服务端程序 |---IMyService.h：自定义的MyService服务的头文件 |---IMyService.cpp：自定义的MyService服务 |---android.mk：源码build文件

1.1 服务端

alps/frameworks/native/cmds/NativeBinderDemo/ServerDemo.cpp

获取ServiceManager，注册service.myservice服务到ServiceManager，启动服务。

1 2 3 4 5 6 7 8 9

#include "IMyService.h" int main() sp < IServiceManager > sm = defaultServiceManager(); //获取service manager引用 sm->addService(String16("service.myservice"), new BnMyService()); //注册名为"service.myservice"的服务到service manager ProcessState::self()->startThreadPool(); //启动线程池 IPCThreadState::self()->joinThreadPool(); //把主线程加入线程池 return 0;

1.2 客户端

alps/frameworks/native/cmds/NativeBinderDemo/ClientDemo.cpp

获取ServiceManager，拿到service.myservice服务，再进行类型转换成IMyService，最后调用远程方法sayHello()

1 2 3 4 5 6 7 8 9

#include "IMyService.h" int main() sp < IServiceManager > sm = defaultServiceManager(); //获取service manager引用 sp < IBinder > binder = sm->getService(String16("service.myservice"));//获取名为"service.myservice"的binder接口 sp<IMyService> cs = interface_cast < IMyService > (binder);//将biner对象转换为强引用类型的IMyService cs->sayHello();//利用binder引用调用远程sayHello()方法 return 0;

1.3 MyService

alps/frameworks/native/cmds/NativeBinderDemo/IMyService.h

申明IMyService，申明BpMyService（Binder客户端），申明BnMyService（Binder的服务端）。

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

#ifndef MY_SERVICE_DEMO #define MY_SERVICE_DEMO #include <stdio.h> #include <binder/IInterface.h> #include <binder/Parcel.h> #include <binder/IBinder.h> #include <binder/Binder.h> #include <binder/ProcessState.h> #include <binder/IPCThreadState.h> #include <binder/IServiceManager.h> using namespace android; namespace android class IMyService : public IInterface public: DECLARE_META_INTERFACE(MyService); //使用宏，申明MyService virtual void sayHello()=0; //定义方法 ; //定义命令字段 enum HELLO = 1, ; //申明客户端BpMyService class BpMyService: public BpInterface<IMyService> public: BpMyService(const sp<IBinder>& impl); virtual void sayHello(); ; //申明服务端BnMyService class BnMyService: public BnInterface<IMyService> public: virtual status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags = 0); virtual void sayHello(); ; #endif

alps/frameworks/native/cmds/NativeBinderDemo/IMyService.cpp

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

#include "IMyService.h" namespace android IMPLEMENT_META_INTERFACE(MyService, "android.demo.IMyService"); //使用宏，完成MyService定义 //客户端 BpMyService::BpMyService(const sp<IBinder>& impl) : BpInterface<IMyService>(impl) // 实现客户端sayHello方法 void BpMyService::sayHello() printf("BpMyService::sayHello\\n"); Parcel data, reply; data.writeInterfaceToken(IMyService::getInterfaceDescriptor()); remote()->transact(HELLO, data, &reply); printf("get num from BnMyService: %d\\n", reply.readInt32()); //服务端，接收远程消息，处理onTransact方法 status_t BnMyService::onTransact(uint_t code, const Parcel& data, Parcel* reply, uint32_t flags) switch (code) case HELLO: //收到HELLO命令的处理流程 printf("BnMyService:: got the client hello\\n"); CHECK_INTERFACE(IMyService, data, reply); sayHello(); reply->writeInt32(2015); return NO_ERROR; break; default: break; return NO_ERROR; // 实现服务端sayHello方法 void BnMyService::sayHello() printf("BnMyService::sayHello\\n"); ;

1.4 Android.mk

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28

LOCAL_PATH := $(call my-dir) include $(CLEAR_VARS) LOCAL_SHARED_LIBRARIES := \\ libcutils \\ libutils \\ libbinder LOCAL_MODULE := ServerDemo LOCAL_SRC_FILES := \\ IMyService.cpp \\ ServerDemo.cpp LOCAL_MODULE_TAGS := optional include $(BUILD_EXECUTABLE) include $(CLEAR_VARS) LOCAL_SHARED_LIBRARIES := \\ libcutils \\ libutils \\ libbinder LOCAL_MODULE := ClientDemo LOCAL_SRC_FILES := \\ IMyService.cpp \\ ClientDemo.cpp LOCAL_MODULE_TAGS := optional include $(BUILD_EXECUTABLE)

1.5 原理图

1.6 运行

编译：
mm alps/frameworks/native/cmds/NativeBinderDemo目录，然后到alps/out/target/product/Project/system/bin/会生成ClientDemo和ServerDemo

执行：

1 2 3

adb remount adb push ServerDemo /system/bin adb push ClientDemo /system/bin

 

开两个窗口分别执行下面两个命令便可以看到结果了：
adb shell system/bin/ServerDemo ， adb shell system/bin/ClientDemo

二、JavaFramework Binder

源码目录结构:

alps/frameworks/base/cmds/FrameworkBinderDemo/

1 2 3 4 5 6 7 8

|-Server端 |---ServerDemo.java：可执行程序 |---IMyService.java: 定义IMyService接口 |---MyService.java：定义MyService |-Client端 |---ClientDemo.java：可执行程序 |---IMyService.java: 与Server端完全一致 |---MyServiceProxy.java：定义MyServiceProxy

2.1 Server端

(1)ServerDemo.java

可执行程序

1 2 3 4 5 6 7 8 9 10 11 12

public class ServerDemo public static void main(String[] args) System.out.println("MyService Start"); //准备Looper循环执行 Looper.prepareMainLooper(); //设置为前台优先级 android.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_FOREGROUND); //注册服务 ServiceManager.addService("MyService", new MyService()); Looper.loop();

(2)IMyService.java

定义sayHello()方法，DESCRIPTOR属性

1 2 3 4 5

public interface IMyService extends IInterface static final java.lang.String DESCRIPTOR = "com.yuanhh.frameworkBinder.MyServer"; public void sayHello(String str) throws RemoteException ; static final int TRANSACTION_say = android.os.IBinder.FIRST_CALL_TRANSACTION;

(3)MyService.java

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

public class MyService extends Binder implements IMyService public MyService() this.attachInterface(this, DESCRIPTOR); @Override public IBinder asBinder() return this; /** 将MyService转换为IMyService接口 **/ public static com.yuanhh.frameworkBinder.IMyService asInterface( android.os.IBinder obj) if ((obj == null)) return null; android.os.IInterface iInterface = obj.queryLocalInterface(DESCRIPTOR); if (((iInterface != null)&&(iInterface instanceof com.yuanhh.frameworkBinder.IMyService))) return ((com.yuanhh.frameworkBinder.IMyService) iInterface); return null; /** 服务端，接收远程消息，处理onTransact方法 **/ @Override protected boolean onTransact(int code, Parcel data, Parcel reply, int flags) throws RemoteException switch (code) case INTERFACE_TRANSACTION: reply.writeString(DESCRIPTOR); return true; case TRANSACTION_say: data.enforceInterface(DESCRIPTOR); String str = data.readString(); sayHello(str); reply.writeNoException(); return true; return super.onTransact(code, data, reply, flags); /** 自定义sayHello()方法 **/ @Override public void sayHello(String str) System.out.println("MyService:: Hello, " + str);

(4) Android.mk

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_SRC_FILES := $(call all-subdir-java-files) LOCAL_MODULE := ServerDemo LOCAL_MODULE_TAGS := optional include $(BUILD_JAVA_LIBRARY) include $(CLEAR_VARS) LOCAL_MODULE := ServerDemo LOCAL_MODULE_TAGS := optional LOCAL_MODULE_PATH := $(TARGET_OUT)/bin LOCAL_MODULE_CLASS := UTILITY_EXECUTABLES LOCAL_SRC_FILES := ServerDemo include $(BUILD_PREBUILT)

(5) ServerDemo

1 2 3

base=/system export CLASSPATH=$base/framework/ServerDemo.jar exec app_process $base/bin com.shun.frameworkBinder.ServerDemo "$@"

2.2 Client端

(1)ClientDemo.java

可执行程序

1 2 3 4 5 6 7 8 9 10

public class ClientDemo public static void main(String[] args) throws RemoteException System.out.println("Client start"); IBinder binder = ServiceManager.getService("MyService"); //获取名为"MyService"的服务 IMyService myService = new MyServiceProxy(binder); //创建MyServiceProxy对象 myService.sayHello("binder"); //通过MyServiceProxy对象调用接口的方法 System.out.println("Client end");

(2)IMyService.java

与Server端的IMyService是一致，基本都是拷贝一份过来。

(3)MyServiceProxy.java

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32

public class MyServiceProxy implements IMyService private android.os.IBinder mRemote; //代表BpBinder public MyServiceProxy(android.os.IBinder remote) mRemote = remote; public java.lang.String getInterfaceDescriptor() return DESCRIPTOR; /** 自定义的sayHello()方法 **/ @Override public void sayHello(String str) throws RemoteException android.os.Parcel _data = android.os.Parcel.obtain(); android.os.Parcel _reply = android.os.Parcel.obtain(); try _data.writeInterfaceToken(DESCRIPTOR); _data.writeString(str); mRemote.transact(TRANSACTION_say, _data, _reply, 0); _reply.readException(); finally _reply.recycle(); _data.recycle(); @Override public IBinder asBinder() return mRemote;

(4) Android.mk

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

LOCAL_PATH:= $(call my-dir) include $(CLEAR_VARS) LOCAL_SRC_FILES := $(call all-subdir-java-files) LOCAL_MODULE := ClientDemo LOCAL_MODULE_TAGS := optional include $(BUILD_JAVA_LIBRARY) include $(CLEAR_VARS) LOCAL_MODULE := ClientDemo LOCAL_MODULE_TAGS := optional LOCAL_MODULE_PATH := $(TARGET_OUT)/bin LOCAL_MODULE_CLASS := UTILITY_EXECUTABLES LOCAL_SRC_FILES := ClientDemo include $(BUILD_PREBUILT)

(5) ClientDemo

1 2 3

base=/system export CLASSPATH=$base/framework/ClientDemo.jar exec app_process $base/bin com.shun.frameworkBinder.ClientDemo "$@"

2.3 原理图

2.4 运行

编译：

mm alps/frameworks/base/cmds/FrameworkBinderDemo/目录，然后：
alps/out/target/product/Project/system/bin/ 生成ClientDemo和ServerDemo
alps/out/target/product/Project/system/framework/ 生成ClientDemo.jar和ServerDemo.jar。

执行：

1 2 3 4 5

adb remount adb push ServerDemo /system/bin adb push ClientDemo /system/bin adb push ServerDemo.jar /system/framework/ adb push ClientDemo.jar /system/framework/

开两个窗口分别执行下面两个命令便可以看到结果了：
adb shell system/bin/ServerDemo ， adb shell system/bin/ClientDemo

 

文章非常好，转自 http://maoao530.github.io/2016/12/25/android-binder-02/