android之aidl进程间通讯数据传输

一、前言

AIDL是Android中IPC（Inter-Process Communication）方式中的一种，AIDL是Android Interface definition language的缩写，AIDL的作用是绑定一个其他APP的service，用于进程间的通讯。

在Android系统中，每个进程都运行在一块独立的内存中，在其中完成自己的各项活动，与其他进程都分隔开来。可是有时候我们又有应用间进行互动的需求，比较传递数据或者任务委托等，AIDL就是为了满足这种需求而诞生的。通过AIDL，可以在一个进程中获取另一个进程的数据和调用其暴露出来的方法，从而满足进程间通信的需求。

二、使用

1、创建服务项目

（1）定义aidl接口UserRemoteService和实体类User.aidl

UserRemoteService.aidl

package com.example.server.user;import com.example.server.user.User;
interface UserRemoteService {User getUserByid(int id);int addUser(in  User user);//in 为客户端传输数据到服务端，out 为服务端传输数据到客户端void showToast(String msg);
}

User.aidl

package com.example.server.user;
parcelable User;

（2）编写java代码

User.java

public class User implements Parcelable, Serializable {private int id;private String username;private String password;public User() {}public User(int id, String username, String password) {this.id = id;this.username = username;this.password = password;}public User(Parcel in) {id = in.readInt();username = in.readString();password = in.readString();}public static final Creator<User> CREATOR = new Creator<User>() {@Overridepublic User createFromParcel(Parcel in) {return new User(in);}@Overridepublic User[] newArray(int size) {return new User[size];}};public int getId() {return id;}public void setId(int id) {this.id = id;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public String getPassword() {return password;}public void setPassword(String password) {this.password = password;}@Overridepublic int describeContents() {return 0;}@Overridepublic void writeToParcel(Parcel parcel, int flags) {parcel.writeInt(id);parcel.writeString(username);parcel.writeString(password);}@Overridepublic String toString() {return "User{" +"id=" + id +", username='" + username + '\'' +", password='" + password + '\'' +'}';}
}

注意：在构造函数中读取数据，读取的顺序要和写入的顺序一样，必须按照成员变量声明的顺序来，不然对象传输会丢失数据！已踩坑！
（3）编写服务service

UsersService.java

public class UsersService extends Service {@Overridepublic void onCreate() {super.onCreate();}@Overridepublic int onStartCommand(Intent intent, int flags, int startId) {return super.onStartCommand(intent, flags, startId);}@Nullable@Overridepublic IBinder onBind(Intent intent) {return new UserRemoteService.Stub(){@Overridepublic User getUserByid(int id) throws RemoteException {User user = new User(id,"123456","lss0555");return user;}@Overridepublic int addUser(User user) throws RemoteException {Log.e("添加用户：",""+user.toString());return 1;}@Overridepublic void showToast(String msg) throws RemoteException {Handler handler=new Handler(Looper.getMainLooper());handler.post(new Runnable(){public void run(){Toast.makeText(getApplicationContext(), "服务提示："+msg, Toast.LENGTH_LONG).show();}});}};}
}

（4）配置启动服务

在 AndroidManifest.xml 声明服务

<service android:name=".service.UsersService"android:enabled="true"android:exported="true"><intent-filter><action android:name="com.example.server.service.UsersService"/></intent-filter>
</service>

在界面种进行启动服务

Intent service = new Intent(getApplicationContext(),UsersService.class);
startService(service);

2、创建客户端项目

定义aidl
将服务的User.aidl、User.java、UserRemoteService.aidl复制到项目下，文件的路径必须一致！

测试类，连接远程服务，调用

MainActivity.java

public class MainActivity extends AppCompatActivity {private UserRemoteService userRemoteService;private ServiceConnection conn = new ServiceConnection() {@Overridepublic void onServiceDisconnected(ComponentName name) {Toast.makeText(getApplicationContext(),"服务已断开",Toast.LENGTH_SHORT).show();userRemoteService = null;}@Overridepublic void onServiceConnected(ComponentName name, IBinder service) {Toast.makeText(getApplicationContext(),"服务连接成功",Toast.LENGTH_SHORT).show();userRemoteService = UserRemoteService.Stub.asInterface(service);}};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);Intent intent = new Intent();intent.setPackage("com.example.server");intent.setAction("com.example.server.service.UsersService");bindService(intent, conn, Service.BIND_AUTO_CREATE);}//获取用户信息public void getUserInfo(View view) {try {User user = userRemoteService.getUserByid(888);Log.e("用户信息：",""+user.toString());} catch (RemoteException e) {e.printStackTrace();}}//添加用户public void addUser(View view) {try {User user = new User(33, "lss0555", "123");int addUser = userRemoteService.addUser(user);Toast.makeText(getApplicationContext(),"结果："+addUser,Toast.LENGTH_SHORT).show();} catch (RemoteException e) {e.printStackTrace();}}//提示功能public void maketip(View view) {try {userRemoteService.showToast("hello world");} catch (RemoteException e) {e.printStackTrace();}}@Overrideprotected void onDestroy() {super.onDestroy();if(conn!=null){unbindService(conn);}}
}

测试：

com.example.server E/添加用户：: User{id=33, username='lss0555', password='123'}com.example.client E/用户信息：: User{id=888, username='123456', password='lss0555'}