GlobalThis替代方案有哪些？

GlobalThis替代方案

HarmonyOS

放大电路

2024-05-26 17:55:47

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回答 1

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回答 1

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背景

ArkTS语法不支持直接使用globalThis。

解决方案

通过一个单例的map来做中转

import common from '@ohos.app.ability.common'; 
  
// 构造单例对象 
export class GlobalThis { 
  private constructor() {} 
  private static instance: GlobalThis; 
  private _uiContexts = new Map<string, common.UIAbilityContext>(); 
  private value = ''; 
  
  public static getInstance(): GlobalThis { 
    if (!GlobalThis.instance) { 
      GlobalThis.instance = new GlobalThis(); 
    } 
    return GlobalThis.instance; 
  } 
  
  getContext(key: string): common.UIAbilityContext | undefined { 
    return this._uiContexts.get(key); 
  } 
  
  setContext(key: string, value: common.UIAbilityContext): void { 
    this._uiContexts.set(key, value); 
  } 
  
  setValue(value:string){ 
    this.value = value 
  } 
  
  getValue():string{ 
    return this.value 
  } 
}

使用

import { GlobalThis } from '../utils/globalThis'; 
  
@Entry 
@Component 
struct Index { 
  @State value:string = GlobalThis.getInstance().getValue() 
  
  build() { 
    Row() { 
      Column() { 
        Text(this.value) 
          .fontSize(50) 
          .fontWeight(FontWeight.Bold) 
        Button("setValue") 
          .fontSize(50) 
          .fontWeight(FontWeight.Bold) 
          .onClick(() => { 
            GlobalThis.getInstance().setValue("TEST") 
          }) 
        Button("setValue") 
          .fontSize(50) 
          .fontWeight(FontWeight.Bold) 
          .onClick(() => { 
            this.value =  GlobalThis.getInstance().getValue() 
          }) 
      } 
      .width('100%') 
    } 
    .height('100%') 
  } 
}