Is your phone just a phone? No! In the world of HarmonyOS, it can become much more. Today, let’s discuss the device virtualization technology of HarmonyOS, a cutting-edge technology that allows your phone to instantly transform into a smart home control center, managing your home’s lights, curtains, and refrigerator—all without the need to purchase expensive dedicated devices, just using the phone you hold every day!
What is virtualization technology?
In simple terms, it allows one device to “pretend” to be another device. Impressive, right?
The device virtualization in HarmonyOS differs from traditional virtual machine technology; it resembles a “possession” between devices. For example, your phone can “possess” a smart speaker, transforming it into an extension of your phone—not just simple remote control, but a true sharing and integration of capabilities. This is where HarmonyOS’s proud “distributed soft bus” comes into play.
How about traditional smart homes? A bunch of apps, seven or eight accounts, and dozens of interfaces to switch back and forth… it’s frustrating! HarmonyOS’s virtualization technology integrates all of this,allowing one interface to control all devices, and it can proactively adjust the home state based on your habits. Isn’t this the smart home hub we’ve always dreamed of?
Technical Principles: It’s More Than Just a Remote Control
The device virtualization in HarmonyOS is based on two core technologies: the “super terminal” and the “distributed soft bus.” What’s their relationship? Let’s put it this way—
The super terminal is like a city map, showing you what devices are around; the distributed soft bus is like the subway lines connecting various locations, responsible for communication between devices. Together, they form the infrastructure for seamless collaboration between devices.
1// Simplified code example for connecting nearby devices
2import deviceManager from '@ohos.distributedDeviceManager';
3
4// Discover nearby devices and establish connections
5function discoverNearbyDevices() {
6 // Define discovery type as all devices
7 const subscribeInfo = {
8 subscribeId: 1,
9 mode: 0xAA, // Discover all nearby devices
10 medium: 2, // COAP method
11 freq: 2, // High-frequency discovery
12 isSameAccount: false,
13 isWakeRemote: true
14 };
15
16 // Start device discovery
17 deviceManager.createDeviceManager('com.example.smarthome').then((dmInstance) => {
18 // Device discovery callback
19 dmInstance.on('deviceFound', (data) => {
20 console.info('Discovered device: ' + JSON.stringify(data));
21 // Here you can add the device to the device list
22 });
23
24 // Start device discovery
25 dmInstance.startDeviceDiscovery(subscribeInfo);
26 }).catch((error) => {
27 console.error('Failed to create device manager: ' + JSON.stringify(error));
28 });
29}
Feeling a bit dizzy looking at the code? No worries! The key is to understand—devices in HarmonyOS do not require complex pairing; as long as they are on the same network, they can almost connect and use immediately. It’s as natural as plugging a USB drive into a computer!
Practical Application: Turning Your Phone into a Smart Home Hub
Without further ado, let’s get hands-on!
The first step is to ensure your phone is running HarmonyOS (HarmonyOS 3.0 or above). Don’t have it? Well, just be envious… just kidding!
Next, we need DevEco Studio to develop a simple smart home control application. After installation, create a new project and select the “Stage model”—make sure not to select the FA model, as that is an outdated architecture; new applications use Stage.
HarmonyOS Stage model project creation interface
Here comes the critical step! We need to add distributed device management capabilities to the application. Open the <span>module.json5</span> file:
1{
2 "module": {
3 // ...other configurations
4 "abilities": [
5 {
6 // ...
7 "permissions": [
8 "ohos.permission.DISTRIBUTED_DEVICE_STATE_CHANGE",
9 "ohos.permission.GET_DISTRIBUTED_DEVICE_INFO",
10 "ohos.permission.DISTRIBUTED_SOFTBUS_CENTER"
11 ]
12 }
13 ]
14 }
15}
These permissions are—super important! Without them, your application will struggle to function.
Next is the UI part; ArkUI provides a complete set of smart home components, and using the <span>@Component</span> decorator, you can quickly create custom components:
1@Component
2struct SmartHomeControl {
3 @State lightStatus: boolean = false;
4 @State temperature: number = 24;
5
6 build() {
7 Column() {
8 Text('Living Room Smart Control')
9 .fontSize(24)
10 .fontWeight(FontWeight.Bold)
11 .margin({bottom: 20})
12
13 Row({space: 20}) {
14 Button('Light')
15 .backgroundColor(this.lightStatus ? '#FF6B00' : '#CCCCCC')
16 .onClick(() => {
17 this.toggleLight();
18 })
19
20 Slider({
21 value: this.temperature,
22 min: 16,
23 max: 32,
24 step: 1
25 })
26 .onChange((value: number) => {
27 this.temperature = value;
28 this.setTemperature(value);
29 })
30
31 Text(`${this.temperature}°C`)
32 .fontSize(20)
33 }
34 }
35 .width('100%')
36 .padding(20)
37 }
38
39 // Control light
40 toggleLight() {
41 // Here call distributed capabilities to control actual devices
42 // Actual code omitted...
43 this.lightStatus = !this.lightStatus;
44 }
45
46 // Set temperature
47 setTemperature(temp: number) {
48 // Actual control code omitted...
49 }
50}
Pitfalls and Solutions Encountered
During development, I encountered several pitfalls. Here are a few:
-
Unstable device connection – Initially, during testing, the devices kept disconnecting. After much hassle, I discovered that both WiFi and Bluetooth needed to be turned on! HarmonyOS device discovery uses a combination of two protocols.
-
Permission application errors – When applying for permissions, if you directly copy the code from the official documentation, it will likely throw an error. Why? Because… the permission names in the documentation are often updated, but the code examples do not keep up! Always check the latest API reference.
-
Real device debugging issues – At first, I could never connect to the devices, later realizing that USB debugging was not enabled. By going to “Settings → About Phone” and clicking the version number seven times, you can enable developer options.
Once, while working on temperature control, I mixed up Celsius and Fahrenheit… resulting in the air conditioning going from hot to cold, almost making my family think it was haunted! Remember, China uses Celsius, while the API may default to Fahrenheit, so be sure to handle unit conversions properly.
Practical Applications: More Than Just Fun
What is the practicality of this technology? There are so many applications!
For instance, smart care for the elderly—you can view environmental data from your parents’ home in real-time on your phone, automatically turning on the air conditioning if the temperature is too high, and alerting you in case of anomalies.
Or smart energy-saving—when everyone leaves home, the system automatically turns off unnecessary appliances, saving on electricity bills while being environmentally friendly.
Recently, I worked on a project where the client had a mischievous child who loved to press appliance switches. After using HarmonyOS virtualization technology, the parents’ phones could remotely lock certain physical buttons on devices, allowing control only through authorized phones. Parents are at ease, and the child is safe.
Looking to the Future
The device virtualization technology of HarmonyOS is still rapidly developing. In the future, we may see more exciting application scenarios: seamless integration of in-car systems with phones, instant connectivity of office devices, and even remote monitoring and control of medical devices…
Want to learn this technology? Get started! Begin with small examples, like creating a simple light control, and gradually expand. Remember, programming is a craft; just watching won’t make you proficient.
By the way, have you ever thought about using HarmonyOS’s device virtualization technology to solve any problems in your life? Or what do you think is the biggest obstacle to this technology? Share your thoughts in the comments!