harmonyOS developer

HarmonyOS Developer Skills

Core Rules

Development Environment

ArkUI Basics

Components

// Basic component
@Entry
@Component
struct Index {
  @State message: string = 'Hello World'
  build() {
    Column() {
      Text(this.message)
        .fontSize(50)
        .fontWeight(FontWeight.Bold)
    }
    .alignItems(HorizontalAlign.Center)
    .width('100%')
    .height('100%')
  }
}

State Management

// @State - Component internal state
@State count: number = 0
// @Prop - Parent component prop
@Prop message: string
// @Link - Two-way binding
@Link childCount: number
// @Observed + @ObjectLink - Deep observation
@Observed
class Person {
  name: string = ''
  age: number = 0
}
@ObjectLink person: Person

Lifecycle

// Component lifecycle
aboutToAppear() {}    // About to display
onDidBuild() {}       // Build complete
aboutToDisappear() {} // About to destroy

Common Components

Layouts

// Linear layout
Column() { }  // Vertical
Row() { }     // Horizontal
// Flex layout
Flex() { 
  direction: FlexDirection.Row 
}
// Grid layout
Grid() { 
  columnsTemplate: '1fr 1fr 1fr' 
}
// Stack
Stack() { }

Routing

import router from '@ohos.router'
// Navigate
router.pushUrl('pages/Detail')
// Go back
router.back()
// With params
router.pushUrl({
  url: 'pages/Detail',
  params: { id: 123 }
})
// Get params
const params = router.getParams()

Network Requests

import http from '@ohos.net.http'
let httpRequest = http.createHttp()
httpRequest.request(
  'https://api.example.com/data',
  {
    method: http.RequestMethod.GET,
    header: { 'Content-Type': 'application/json' }
  },
  (err, data) => {
    if (!err) {
      console.log(JSON.stringify(data.result))
    }
  }
)

Local Storage

import preferences from '@ohos.data.preferences'
// Write
let preferences = await preferences.getPreferences(context, 'myPrefs')
await preferences.put('username', 'tom')
await preferences.flush()
// Read
let value = await preferences.get('username', 'default')

Permissions

import abilityAccessCtrl from '@ohos.abilityAccessCtrl'
// Declare in module.json5
// "requestPermissions": [
//   { "name": "ohos.permission.INTERNET" }
// ]
// Request at runtime
let atManager = abilityAccessCtrl.createAtManager()
atManager.requestPermissionsFromUser(context, ['ohos.permission.INTERNET'])

Common Permissions

Build & Signing

1. DevEco Studio → Build → Build Hap 2. Configure signing in Project Structure → Signing Configs 3. Requires .p12 certificate and .cer public key 4. Use debug signing for development, release for production

Quick Reference

| Need | Solution | |------|----------| | State management | @State, @Prop, @Link, @Observed | | Lists | List + ListItem | | Network | @ohos.net.http | | Storage | @ohos.data.preferences | | Routing | router.pushUrl() | | Toast | promptAction.showToast() | | Dialog | dialog.showDialog() |

Learning Resources