语法 - 比特日记

语法

build

build()里面，有且仅有1个根元素

定义


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1let h: string = 'hi'
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3const n: number = 5

函数


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 1@Entry
 2@Component
 3struct Index {
 4  username: string = 'Yang'
 5
 6  play() {
 7  }
 8
 9  show = () => {
10    this.play()
11    this.username = 'King'
12  }
13
14  func = (): void => {
15  }
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17  // 类型转换
18  num = Number('100')
19}

数组


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1export class User {
2  id: number = 1
3  name: string = 'Your'
4}


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1import { User } from '../utils/User'
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4let users1: string[] = ['Hellen', 'Jim']
5let users2: Array<string> = ['Hob']
6let users3: Array<User> = [new User(), new User()]
7let users5: Array<User> = [new User(), { id: 1, name: 'Haha' }]

枚举


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1enum OrderStatus {
2  payFail = 0,
3  paySuccess = 1,
4  payTimeout = 2
5}
6
7if (OrderStatus.paySuccess == 1) {
8  
9}


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 1@Entry
 2@Component
 3struct Index {
 4  @State message: string = 'Hello World';
 5
 6  build() {
 7    Column() {
 8      Text('字体样式')
 9        .fontWeight(FontWeight.Bold)
10        .textAlign(TextAlign.Center)
11        .fontStyle(FontStyle.Italic)
12    }
13    .height(100)
14    .width('100%')
15  }
16}

联合类型


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 1class User {
 2  id: number
 3
 4  constructor(id: number) {
 5    this.id = id
 6  }
 7}
 8
 9@Entry
10@Component
11struct Index {
12  @State message: string = 'Hello World';
13  @State user: User | null | undefined = null
14  username: string | undefined = undefined
15}

键值对


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 1@Entry
 2@Component
 3struct Index {
 4  @State map: Record<string, string> = {
 5    'name': 'Your',
 6    'position': 'Programmer'
 7  }
 8
 9  build() {
10  }
11}

横线


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1Divider()

颜色

英文单词、16进制、RGB、枚举


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1backgroundColor("rgb(201,202,245)")

主轴


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1justifyContent(FlexAlign.Start) // 主轴方向
2alignItems(HorizontalAlign.Start) // 侧轴方向