How to use AIDL for cross-process communication

The steps for cross-process communication using AIDL (Android Interface Definition Language) are as follows:

1. Create AIDL file:

   1. Create an AIDL file in your Android project with an extension of .aidleg IMyService.aidl.
   2. Define interfaces and methods in AIDL files that will be used for cross-process communication

      // IMyService.aidl
      interface IMyService {
          void sendData(int data);
          String getData();
      }
      

2. Implement the AIDL interface:

   Create a Service in the server process and implement the AIDL interface just defined.

   public class MyService extends Service {
       private final IMyService.Stub binder = new IMyService.Stub() {
           @Override
           public void sendData(int data) {
               // 处理客户端发送的数据
           }
   
           @Override
           public String getData() {
               // 返回需要传递给客户端的数据
               return "Hello, client!";
           }
       };
   
       @Nullable
       @Override
       public IBinder onBind(Intent intent) {
           return binder;
       }
   }
   

3. Connect to server process:
   1. In the client process, use the code generated by AIDL to create a ServiceConnection object, which is used to connect to the Service of the server process and communicate across processes.

      private ServiceConnection serviceConnection = new ServiceConnection() {
          @Override
          public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
              // 连接到服务端进程的Service成功
              // 将IBinder对象转换为AIDL接口对象
              IMyService myService = IMyService.Stub.asInterface(iBinder);
      
              try {
                  // 调用服务端的方法进行跨进程通信
                  myService.sendData(123);
                  String result = myService.getData();
                  // 处理返回的数据
              } catch (RemoteException e) {
                  e.printStackTrace();
              }
          }
      
          @Override
          public void onServiceDisconnected(ComponentName componentName) {
              // 与服务端进程的Service断开连接
          }
      };
      
      // 绑定到服务端进程的Service
      Intent intent = new Intent();
      intent.setComponent(new ComponentName("服务端进程的包名", "服务端进程的Service类名"));
      bindService(intent, serviceConnection, Context.BIND_AUTO_CREATE);
      

      Through the above steps, you can use AIDL for cross-process communication. It should be noted that you need to set the package name and Service class name of the server process to correct values ​​so as to correctly connect to the Service of the server process. At the same time, AIDL also supports the definition of callback methods in the interface to achieve two-way communication. Detailed usage and examples can be found in the Android development documentation.