Why HarmonyOS Is the Next Big Platform for Mobile Developers

1. HarmonyOS Overview

1.1 What is HarmonyOS?

HarmonyOS is Huawei's distributed operating system designed for all scenarios, based on a micro‑kernel architecture to enable fast connection, capability sharing, and resource sharing across different devices.

1.2 Development Background

Accelerated under the "China‑U.S. competition" context, the OS has seen multiple releases from 2019 to 2024, culminating in HarmonyOS Next, which abandons the AOSP and uses a self‑developed kernel.

Policy and strong technical/market advantages from Huawei.

IoT era post‑advantage: better adaptation to billions of IoT devices compared with Android and iOS.

By the end of March 2024, over 5,000 Android apps are planned to migrate to native HarmonyOS, covering lifestyle, travel, finance, social, productivity, entertainment, and gaming.

1.3 Advantages

Policy support and Huawei's technical strength.

IoT post‑advantage.

Distributed collaboration across devices.

Lightweight service model similar to mini‑programs.

AI‑driven intelligent distribution.

Hardware‑software co‑design AI capabilities.

2. HarmonyOS Application Forms and Development Benefits

2.1 Application Form Advantages

Beyond traditional installable apps, HarmonyOS supports a "mini‑program"‑like meta‑service that runs on demand, with a unified technology stack for both apps and meta‑services, and seamless cross‑device interaction.

2.2 Development Advantages

2.2.1 Distributed Development & Debugging

DevEco Studio provides one‑stop, multi‑device distributed development, including distributed debugging, performance tracing, multi‑device preview, and a "super terminal" that combines multiple simulators and real devices.

Distributed debugging: breakpoint and debug across devices.

Distributed tuning: trace calls, stacks, and performance data.

Dual‑direction preview: UI code preview on multiple devices with live updates.

Super terminal simulation: flexible combination of simulators and real devices.

2.2.2 Multi‑Device Unified Adaptation

HarmonyOS abstracts physical pixels to virtual pixels (vp) for consistent visual size across devices and unifies input events, providing a consistent API similar to web JS APIs.

2.2.3 Flexible Multi‑App Packaging

Hap modules contain code, resources, and third‑party libraries and can be installed independently. An App Pack aggregates one or more Haps, allowing selective installation of modules.

// cjf_stage1/entry/build-profile.json5
{
  "apiType": "stageMode",
  "buildOption": {},
  "targets": [
    {
      "name": "default",
      "runtimeOS": "HarmonyOS"
    },
    {
      "name": "free", // free version
      "runtimeOS": "HarmonyOS",
      "config": { "deviceType": ["phone"] },
      "source": { "pages": ["pages/index"] },
      "resource": { "directories": ["./src/main/resources_default", "./src/main/resources_free"] }
    },
    {
      "name": "pay", // paid version
      "runtimeOS": "HarmonyOS"
    }
  ]
}

2.3 AI Capability Integration

HarmonyOS integrates AI services, offering a one‑stop experience for developers to embed AI features.

3. HarmonyOS Application Technical System

3.1 ArkTS Language

ArkTS extends TypeScript with declarative UI, state management, and concurrency control, forming the primary language for HarmonyOS app development.

Declarative UI

State Management

@StorageLink and AppStorage provide Vue‑like state handling; variables must be decorated to trigger UI updates.

@Component
struct CountDownComponent {
  @Prop count: number;
  test: number = 1;

  build() {
    Column() {
      Text(`You have ${this.count} Nuggets left`)
      Button(`Try again`).onClick(() => { this.count -= this.test })
    }
  }
}

@Entry
@Component
struct ParentComponent {
  @State countValue: number = 10;

  build() {
    Column() {
      Button(`+1`).onClick(() => { this.countValue += 1 })
      CountDownComponent({ count: this.countValue, test: 2 })
    }
  }
}

Concurrency Control

Promise and async/await for I/O‑bound tasks.

TaskPool and Worker for CPU‑intensive or high‑concurrency scenarios.

3.2 ArkUI Framework

Provides UI components, layout, animation, interaction, and rendering. Supports two development paradigms:

Declarative (ArkTS) – data‑driven UI, suited for complex, team‑based projects.

Class‑Web (JS) – familiar to web front‑end developers, using a JS framework to map HTML‑like structures to ArkUI components.

3.3 Ability Concept

Ability abstracts an app's capabilities; UIAbility is the basic unit for UI rendering, similar to Android's Activity or Service.

import UIAbility from '@ohos.app.ability.UIAbility';
import hilog from '@ohos.hilog';

export default class EntryAbility extends UIAbility {
  onCreate(want, launchParam) {
    hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onCreate');
  }
  onBackground() {
    hilog.info(0x0000, 'testTag', '%{public}s', 'Ability onBackground');
  }
}

3.4 ArkCompiler

ArkCompiler compiles ArkTS/TS/JS to platform‑agnostic bytecode (ABC) and provides a runtime that optimizes execution, supports an Actor model, TaskPool, and strict‑mode JavaScript.

// Simple ArkCompiler bytecode example for adding two numbers
function add(a: number, b: number): number {
  .locals 1
  iload a
  iload b
  iadd
  istore result
  iload result
  ireturn
}

4. HarmonyOS Application Development Practice

4.1 Environment Setup

Install the standard DevEco Studio following the official wizard.

4.2 Development & Debugging

Download the official demo projects and run them to deepen understanding.

5. Conclusion

After a decade of mobile internet dominated by Android and iOS, HarmonyOS emerges with strong policy backing and IoT‑focused advantages, offering a fresh platform for developers to stay current with emerging technology trends.