Introduction

HUAWEI OneHop is a core part of Huawei's device distributed technology. Based on the traditional NFC technology, HUAWEI OneHop integrates more short-distance technologies to enable a more efficient interaction and collaboration between a smartphone and other devices with a simple tap.

What You Will Learn

In this CodeLab, you are supposed to create a demo project and integrate the HUAWEI OneHop SDK into the demo to allow the OneHop Kit service work on Linux compatible devices.

Hardware Requirements

• The device runs on the Linux system (with kernel version 3.10 or later recommended).
• The device supports NFC, having an NFC tag supporting reading and writing data.
• The Wi-Fi supports the P2P transfer protocols.

Software Requirements

• The system supports wpa_supplicant 2.6 or later.
• The phone for testing must run EMUI 10.1 or later.

Required Knowledge

• Basic development capability of integrating the OneHop Kit into a device running Linux system.

Development Procedures

(1) Creating a project

The specific procedure depends on the actual development environment. The directory structure for the project is shown as follows:

Upload the project to the Linux compilation environment.

(2) Project compilation

In the Linux compilation environment, run the compilation commands to compile the project. For details, see the README file in the sample code package. The generated onehopkit_demo file is shown as follows:

(3) Configuring environment variables

Configure variables for the Linux environment where the demo program runs. For details about how to configure environment variables, please refer to the README file in the sample code package. After the configuration, you can run the demo program. The following figure shows the commands for configuring environment variables and running the demo program.

Service Process

The following figure shows the overall process.

• The app on the device invokes OneHop Kit to enable Wi-Fi P2P GO mode and write the Wi-Fi data into the NFC tag. In this step, the app on the device needs to invoke the APIs to initialize and enable the OneHop services.
• Users select the file they need to transfer on the phone and tap the phone against the NFC tag on the device.
• The phone obtains the Wi-Fi connection data and establishes a connection with the device.
• The phone sends the image transfer notification, and the OneHop Kit integrated on the device receives the notification, and further sends this notification to the app on the device to start transferring files, pending for user's confirmation.
• User confirms the reception, then the phone sends the file, and the device receives it. After that, the device will send a notification for the app on the device to proceed to the next step. After the app on the device receives the notification, it will start the printing process.

For details on the API definitions, refer to the API Description.

The following shows how OneHop demo program invokes APIs for OneHop printing.
onehop_demo.c

int main()
{
   signal(SIGINT, p_exit);
   InitCallback();
   InitDriverAdapt();
   /* Service Initialization APIs*/
   if (InitOneHop(NULL) != 0) {
       printf("*****Init OneHop failed!*****\n");
       return -1;
   }
   /* OneHop service is running
   * Press Ctrl and C keys to terminate the service
   */
   while (g_running) {
       if (g_serviceEndFlag == SERVICE_STOPPED) {
           g_serviceEndFlag = SERVICE_STARTED;
           printf("#####Start onehop service#####\n");
           if (StartOneHopService(&g_callBack) != 0) {
               printf("*****Start onehop service failed!*****\n");
               if (StopOneHopService() != 0) {
                   printf("*****Stop onehop service failed!*****\n");
                   UninitOneHop();
                   return -1;
               }
               g_serviceEndFlag = SERVICE_STOPPED;
           }
       }
       sleep(1);
   }
   /* Invoke the end OneHop service API */
   printf("#####Stop onehop service#####\n");
   if (StopOneHopService() != 0) {
       printf("*****Stop onehop service failed!*****\n");
       UninitOneHop();
       return -1;
   }
   /* Invoke the deinitialization OneHop service API */
   printf("#####Uninit onehop kit#####\n");
   UninitOneHop();
   return 0;
}

You have successfully completed this CodeLab and learned:

• Setting up a demo and integrate the HUAWEI OneHop SDK into it.
• Completing the initialization, launching, termination, and deinitialization process of the OneHop Kit.

For more information about HUAWEI OneHop, click the following links:
HUAWEI OneHop Introduction

Downloading Source Code