场景：APP-A 服务端，APP-B 客户端。B启动service，通过IBinder，拿到服务端User列表，并向User表中添加人员信息。从而实现两个APP跨进程通讯

一，服务端APP

步骤：1，创建User实体类；2，实现AIDL接口，3，定义service；4，在AndroidManifast.xml配置service
注意：如果通过AIDL传递实体类，必须要继承Parcelable接口

1，创建User实体并实现Parcelable接口

public class User implements Parcelable {
    
    private String name;
    private int age;

    public User(String name, int age) {
    
        this.name = name;
        this.age = age;
    }

    protected User(Parcel in) {
    
        name = in.readString();
        age = in.readInt();
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
    
        dest.writeString(name);
        dest.writeInt(age);
    }

    //rebuild project 后会报找不到readFromParce方法 ，需要在实体类中创建
    public void readFromParcel(Parcel in) {
    
        this.name = in.readString();
        this.age = in.readInt();
    }

    @Override
    public int describeContents() {
    
        return 0;
    }

    public static final Creator<User> CREATOR = new Creator<User>() {
    
        @Override
        public User createFromParcel(Parcel in) {
    
            return new User(in);
        }

        @Override
        public User[] newArray(int size) {
    
            return new User[size];
        }
    };

    @Override
    public String toString() {
    
        return "User{" +
            "name='" + name + '\'' +
            ", age=" + age +
            '}';
    }
}

2，实现AIDL接口（User.aidl，IUserService.aidl)

创建过程：右键–>New–>AIDL–>AIDL File
自定义User类，必须声明parcelable类

// User.aidl
package com.example.demo;

// Declare any non-default types here with import statements
parcelable User;

定义接口用来获取User列表，以及添加人员

in：代表数据只能由客户端传递到服务端
out：代表数据只能由服务端传递到客户端
inout：代表数据可以双向流动

// IUserService.aidl
package com.example.demo;

// Declare any non-default types here with import statements
import com.example.demo.User;
interface IUserService {
    
    /**
     * Demonstrates some basic types that you can use as parameters
     * and return values in AIDL.
     */
    List<User> getList();
    void addUser(in User user);
}

创建完成后Rebuid Project。

3，创建UserService

public class UserService extends Service {
    

    private List<User> userList;

    @Override
    public void onCreate() {
    
        userList = new ArrayList<User>();
        Log.i("userService","service is open");
        initData();
    }

    private void initData() {
    
        User user = new User("xiaoming", 10);
        User user1 = new User("lihong", 12);
        userList.add(user);
        userList.add(user1);
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
    
        return super.onStartCommand(intent, flags, startId);
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
    
        return stub;
    }
    
	private final IUserService.Stub stub = new IUserService.Stub() {
    
        @Override
        public List<User> getList() throws RemoteException {
    
        	//向客户端返回的人员列表
            return userList;
        }

        @Override
        public void addUser(User user) throws RemoteException {
    
        	//客户端向服务端添加的人员信息
            userList.add(user);
            Log.i("UserService",user.toString());
        }
    };
}

4，配置AndroidManifast.xml（exported = true 必须要为true，允许跨进程访问）

 <service
       android:name="com.example.demo.UserService"
       android:enabled="true"
       android:process=":remote"
       android:exported="true"/>

二，客户端APP

步骤：1，将服务端的aidl文件，以及实体类拷贝到客户端（包名需要和服务端一致）；2，bindService启动服务；3，和服务端交互

1，将服务端的aidl文件，和实体类拷贝到客户端。只要保持包名一致就ok。拷贝完毕，Rebuild Project。

2，bindService 启动服务

 serviceConnection = new ServiceConnection() {
    
            @Override
            public void onServiceConnected(ComponentName name, IBinder service) {
    
            	//绑定成功回调
                iUserService = IUserService.Stub.asInterface(service);
                connected = true;
            }

            @Override
            public void onServiceDisconnected(ComponentName name) {
    
                connected = false;
            }
        };

 private void bindService() {
    
 		//第一个参数：服务端包名，第二个参数：服务端UserService类的包名（全路径）
        ComponentName componentName = new ComponentName("com.example.demo", "com.example.demo.UserService");
        Intent intent = new Intent();
        intent.setComponent(componentName);
        boolean result = this.bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
        Log.i(TAG, "bindService: " + result);
    }

注意：在写Demo的时候，一直无法启动service，最后发现需要在AndroidManifest.xml配置queries标签，声明我们App与其交互的包名，配置后即可启动

	//配置服务端的包名	
  <queries>
        <package android:name="com.example.demo" />
  </queries>

3，启动成功后即可数据交互

通过IUserService.Stub.asInterface(service); 将IBinder转成aidl接口，可直接调用其方法

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    

    private static final String TAG = "MainActivity";
    boolean connected = false; //是否链接
    private IUserService iUserService;
    private ServiceConnection serviceConnection;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
    
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.getUserList).setOnClickListener(this);
        findViewById(R.id.sendUser).setOnClickListener(this);
        findViewById(R.id.start_service).setOnClickListener(this);
        init();
    }

    private void init(){
    
        serviceConnection = new ServiceConnection() {
    
            @Override
            public void onServiceConnected(ComponentName name, IBinder service) {
    
                iUserService = IUserService.Stub.asInterface(service);
                connected = true;
            }

            @Override
            public void onServiceDisconnected(ComponentName name) {
    
                connected = false;
            }
        };
    }

    private void bindService() {
    
        ComponentName componentName = new ComponentName("com.example.demo", "com.example.demo.UserService");
        Intent intent = new Intent();
        intent.setComponent(componentName);
        boolean result = this.bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
        Log.i(TAG, "bindService: " + result);
    }

    @Override
    protected void onDestroy() {
    
        super.onDestroy();
        unbindService(serviceConnection);
    }

    @Override
    public void onClick(View v) {
    
        switch (v.getId()) {
    
            case R.id.start_service:
                bindService();
                break;
            case R.id.getUserList:
                if (connected) {
    
                    try {
    
                    	//获取服务器端User列表
                        List<User> userList = iUserService.getList();
                        for (User user : userList) {
    
                            Log.i("MainActivity", user.toString());
                        }
                    } catch (RemoteException e) {
    
                        e.printStackTrace();
                    }
                }
                break;
            case R.id.sendUser:
                if (connected) {
    
                    User user = new User("hanleilei", 15);
                    try {
    
                    	//向服务器端传递人员信息
                        iUserService.addUser(user);
                    } catch (RemoteException e) {
    
                        e.printStackTrace();
                    }
                }
                break;
            default:
                break;
        }
    }
}