鸿蒙 - 验证码功能

let listStr = ""
// 创建一个四个空元素的数组
// let arr: string[] = Array(4)
// for (let i = 0; i < arr.length; i++) {
//   arr[i] = listStr[Math.floor(Math.random() * listStr.length)]
// }@Entry
@Component
struct Day235 {@State message: string = '';@State str:string = ''aboutToAppear(): void {listStr = this.genStr(65,90)+this.genStr(97,122)+this.genStr(48,57)this.str = this.genCode()}genStr(start:number,end:number){let str = ''for (let i = start; i <= end; i++) {str+=String.fromCharCode(i)}return str}genCode(){this.str=''for (let i = 0; i < 4; i++) {let index = Math.floor(Math.random()*62)this.str += listStr[index]}return this.str}build() {Column() {Row(){TextInput({ text: $$this.message }).layoutWeight(1)Text(this.str.toString()).fontSize(50) }Button('验证').onClick(() => {if (this.message.toLowerCase() == this.str.toLowerCase()) {AlertDialog.show({message: 'OK'})} else {AlertDialog.show({message: 'Fail'})}})}.height('100%').width('100%')}
}