IPC系列->AIDL

没有AIDL方式启动目标Activity的方式
ActivityManagerProxy.startActivity

public int startActivity(IApplicationThread caller, String callingPackage, Intent intent,
            String resolvedType, IBinder resultTo, String resultWho, int requestCode,
            int startFlags, ProfilerInfo profilerInfo, Bundle options) throws RemoteException {
    Parcel data = Parcel.obtain();
    Parcel reply = Parcel.obtain();
    data.writeInterfaceToken(IActivityManager.descriptor);
    data.writeStrongBinder(caller != null ? caller.asBinder() : null);
    data.writeString(callingPackage);
    intent.writeToParcel(data, 0);
    data.writeString(resolvedType);
    data.writeStrongBinder(resultTo);
    data.writeString(resultWho);
    data.writeInt(requestCode);
    data.writeInt(startFlags);
    if (profilerInfo != null) {
        data.writeInt(1);
        profilerInfo.writeToParcel(data, Parcelable.PARCELABLE_WRITE_RETURN_VALUE);
    } else {
        data.writeInt(0);
    }
    if (options != null) {
        data.writeInt(1);
        options.writeToParcel(data, 0);
    } else {
        data.writeInt(0);
    }
    mRemote.transact(START_ACTIVITY_TRANSACTION, data, reply, 0);
    reply.readException();
    int result = reply.readInt();
    reply.recycle();
    data.recycle();
    return result;
}

  正如上面代码所示, 如果没有AIDL, 要实现进程间通信, App进行与system_server进程之间进行通信, 需要先将通讯请求转换成序列化的数据, 然后调用transact()函数发送给服务端, 而且还得制定对应的协议, 参数的先后顺序, 而且服务端与客户端都必须一致, 否则就会出错.

参考文章
https://www.zhihu.com/question/39440766
https://blog.csdn.net/xude1985/article/details/9232049
https://blog.csdn.net/tiefeng0606/article/details/51142518