AIDL原理

public static abstract class Stub extends android.os.Binder implements com.example.aidl.IPeopleManager
  {
    private static final java.lang.String DESCRIPTOR = "com.example.aidl.IPeopleManager";
    /** Construct the stub at attach it to the interface. */
    public Stub()
    {
      this.attachInterface(this, DESCRIPTOR);
    }
    /**
     * Cast an IBinder object into an com.example.aidl.IPeopleManager interface,
     * generating a proxy if needed.
     */
     // 我们在onServiceConnected()方法中，就是用这个asInterface()方法，来把Service的onBind()返回的IBinder对象转化为Stub对象或Proxy对象
    public static com.example.aidl.IPeopleManager asInterface(android.os.IBinder obj)
    {
      if ((obj==null)) {
        return null;
      }
       // 寻找本地Stub接口，也就是当前进程的Stub接口
      android.os.IInterface iin = obj.queryLocalInterface(DESCRIPTOR);
      // 如果找到了，就表示和aidl是在一个进程里
      // 否则，就不是一个进程里，比如Client
      if (((iin!=null)&&(iin instanceof com.example.aidl.IPeopleManager))) {
      // 在一个进程里，返回的是Service类里的Stub对象
        return ((com.example.aidl.IPeopleManager)iin);
      }
       // 不在一个进程里，就返回一个Proxy，所以Client获取的是proxy
            // 传入的参数，就是Service的onBind()方法返回值
      return new com.example.aidl.IPeopleManager.Stub.Proxy(obj);
    }
    @Override public android.os.IBinder asBinder()
    {
      return this;
    }
    // 此方法仅用于ipc，如果是一个进程里用不到
    @Override public boolean onTransact(int code, android.os.Parcel data, android.os.Parcel reply, int flags) throws android.os.RemoteException
    {
      java.lang.String descriptor = DESCRIPTOR;
      switch (code)
      {
        case INTERFACE_TRANSACTION:
        {
          reply.writeString(descriptor);
          return true;
        }
        case TRANSACTION_basicTypes:
        {
          data.enforceInterface(descriptor);
          int _arg0;
          _arg0 = data.readInt();
          long _arg1;
          _arg1 = data.readLong();
          boolean _arg2;
          _arg2 = (0!=data.readInt());
          float _arg3;
          _arg3 = data.readFloat();
          double _arg4;
          _arg4 = data.readDouble();
          java.lang.String _arg5;
          _arg5 = data.readString();
          this.basicTypes(_arg0, _arg1, _arg2, _arg3, _arg4, _arg5);
          reply.writeNoException();
          return true;
        }
        case TRANSACTION_getAge:
        {
          data.enforceInterface(descriptor);
          int _result = this.getAge();
          reply.writeNoException();
          reply.writeInt(_result);
          return true;
        }
        case TRANSACTION_getName:
        {
          data.enforceInterface(descriptor);
          java.lang.String _result = this.getName();
          reply.writeNoException();
          reply.writeString(_result);
          return true;
        }
        case TRANSACTION_addPeople:
        {
          data.enforceInterface(descriptor);
          com.example.aidl.People _arg0;
          if ((0!=data.readInt())) {
            _arg0 = com.example.aidl.People.CREATOR.createFromParcel(data);
          }
          else {
            _arg0 = null;
          }
          this.addPeople(_arg0);
          reply.writeNoException();
          return true;
        }
        case TRANSACTION_getPeople:
        {
          data.enforceInterface(descriptor);
          com.example.aidl.People _result = this.getPeople();
          reply.writeNoException();
          if ((_result!=null)) {
            reply.writeInt(1);
            _result.writeToParcel(reply, android.os.Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
          }
          else {
            reply.writeInt(0);
          }
          return true;
        }
        case TRANSACTION_updatePeople:
        {
          data.enforceInterface(descriptor);
          com.example.aidl.People _arg0;
          _arg0 = new com.example.aidl.People();
          com.example.aidl.People _result = this.updatePeople(_arg0);
          reply.writeNoException();
          if ((_result!=null)) {
            reply.writeInt(1);
            _result.writeToParcel(reply, android.os.Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
          }
          else {
            reply.writeInt(0);
          }
          if ((_arg0!=null)) {
            reply.writeInt(1);
            _arg0.writeToParcel(reply, android.os.Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
          }
          else {
            reply.writeInt(0);
          }
          return true;
        }
        case TRANSACTION_updatePeople2:
        {
          data.enforceInterface(descriptor);
          com.example.aidl.People _arg0;
          if ((0!=data.readInt())) {
            _arg0 = com.example.aidl.People.CREATOR.createFromParcel(data);
          }
          else {
            _arg0 = null;
          }
          com.example.aidl.People _result = this.updatePeople2(_arg0);
          reply.writeNoException();
          if ((_result!=null)) {
            reply.writeInt(1);
            _result.writeToParcel(reply, android.os.Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
          }
          else {
            reply.writeInt(0);
          }
          if ((_arg0!=null)) {
            reply.writeInt(1);
            _arg0.writeToParcel(reply, android.os.Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
          }
          else {
            reply.writeInt(0);
          }
          return true;
        }
        default:
        {
          return super.onTransact(code, data, reply, flags);
        }
      }
    }