OpenHarmony页面级UI状态存储：LocalStorage 原创

let para: Record<string,number> = { 'PropA': 47 };
let storage: LocalStorage = new LocalStorage(para); // 创建新实例并使用给定对象初始化
let propA: number | undefined = storage.get('PropA') // propA == 47
let link1: SubscribedAbstractProperty<number> = storage.link('PropA'); // link1.get() == 47
let link2: SubscribedAbstractProperty<number> = storage.link('PropA'); // link2.get() == 47
let prop: SubscribedAbstractProperty<number> = storage.prop('PropA'); // prop.get() = 47
link1.set(48); // two-way sync: link1.get() == link2.get() == prop.get() == 48
prop.set(1); // one-way sync: prop.get()=1; but link1.get() == link2.get() == 48
link1.set(49); // two-way sync: link1.get() == link2.get() == prop.get() == 49

// 创建新实例并使用给定对象初始化
let para:Record<string,number> = { 'PropA': 47 };
let storage: LocalStorage = new LocalStorage(para);

@Component
struct Child {
  // @LocalStorageLink变量装饰器与LocalStorage中的'PropA'属性建立双向绑定
  @LocalStorageLink('PropA') storLink2: number = 1;

  build() {
    Button(`Child from LocalStorage ${this.storLink2}`)
      // 更改将同步至LocalStorage中的'PropA'以及Parent.storLink1
      .onClick(() => this.storLink2 += 1)
  }
}
// 使LocalStorage可从@Component组件访问
@Entry(storage)
@Component
struct CompA {
  // @LocalStorageLink变量装饰器与LocalStorage中的'PropA'属性建立双向绑定
  @LocalStorageLink('PropA') storLink1: number = 1;

  build() {
    Column({ space: 15 }) {
      Button(`Parent from LocalStorage ${this.storLink1}`) // initial value from LocalStorage will be 47, because 'PropA' initialized already
        .onClick(() => this.storLink1 += 1)
      // @Component子组件自动获得对CompA LocalStorage实例的访问权限。
      Child()
    }
  }
}

// 创建新实例并使用给定对象初始化
let para:Record<string,number> = { 'PropA': 47 };
let storage: LocalStorage = new LocalStorage(para);
// 使LocalStorage可从@Component组件访问
@Entry(storage)
@Component
struct CompA {
  // @LocalStorageProp变量装饰器与LocalStorage中的'PropA'属性建立单向绑定
  @LocalStorageProp('PropA') storProp1: number = 1;

  build() {
    Column({ space: 15 }) {
      // 点击后从47开始加1，只改变当前组件显示的storProp1，不会同步到LocalStorage中
      Button(`Parent from LocalStorage ${this.storProp1}`)
        .onClick(() => this.storProp1 += 1)
      Child()
    }
  }
}

@Component
struct Child {
  // @LocalStorageProp变量装饰器与LocalStorage中的'PropA'属性建立单向绑定
  @LocalStorageProp('PropA') storProp2: number = 2;

  build() {
    Column({ space: 15 }) {
      // 当CompA改变时，当前storProp2不会改变，显示47
      Text(`Parent from LocalStorage ${this.storProp2}`)
    }
  }
}

// 构造LocalStorage实例
let para:Record<string,number> = { 'PropA': 47 };
let storage: LocalStorage = new LocalStorage(para);
// 调用link9+接口构造'PropA'的双向同步数据，linkToPropA 是全局变量
let linkToPropA: SubscribedAbstractProperty<object> = storage.link('PropA');

@Entry(storage)
@Component
struct CompA {

  // @LocalStorageLink('PropA')在CompA自定义组件中创建'PropA'的双向同步数据，初始值为47，因为在构造LocalStorage已经给“PropA”设置47
  @LocalStorageLink('PropA') storLink: number = 1;

  build() {
    Column() {
      Text(`incr @LocalStorageLink variable`)
        // 点击“incr @LocalStorageLink variable”，this.storLink加1，改变同步回storage，全局变量linkToPropA也会同步改变

        .onClick(() => this.storLink += 1)

      // 并不建议在组件内使用全局变量linkToPropA.get()，因为可能会有生命周期不同引起的错误。
      Text(`@LocalStorageLink: ${this.storLink} - linkToPropA: ${linkToPropA.get()}`)
    }
  }
}

let ls:Record<string,number> = { 'countStorage': 1}
let storage:LocalStorage = new LocalStorage(ls);
@Component
struct Child {
  // 子组件实例的名字
  label: string = 'no name';
  // 和LocalStorage中“countStorage”的双向绑定数据
  @LocalStorageLink('countStorage') playCountLink: number = 0;

  build() {
    Row() {
      Text(this.label)
        .width(50).height(60).fontSize(12)
      Text(`playCountLink ${this.playCountLink}: inc by 1`)
        .onClick(() => {
          this.playCountLink += 1;
        })
        .width(200).height(60).fontSize(12)
    }.width(300).height(60)
  }
}

@Entry(storage)
@Component
struct Parent {
  @LocalStorageLink('countStorage') playCount: number = 0;

  build() {
    Column() {
      Row() {
        Text('Parent')
          .width(50).height(60).fontSize(12)
        Text(`playCount ${this.playCount} dec by 1`)
          .onClick(() => {
            this.playCount -= 1;
          })
          .width(250).height(60).fontSize(12)
      }.width(300).height(60)

      Row() {
        Text('LocalStorage')
          .width(50).height(60).fontSize(12)
        Text(`countStorage ${this.playCount} incr by 1`)
          .onClick(() => {
            storage.set<number|undefined>('countStorage', Number(storage.get<number>('countStorage')) + 1);
          })
          .width(250).height(60).fontSize(12)
      }.width(300).height(60)

      Child({ label: 'ChildA' })
      Child({ label: 'ChildB' })

      Text(`playCount in LocalStorage for debug ${storage.get<number>('countStorage')}`)
        .width(300).height(60).fontSize(12)
    }
  }
}

// EntryAbility.ts
import UIAbility from '@ohos.app.ability.UIAbility';
import window from '@ohos.window';
let para:Record<string,number> = { 'PropA': 47 };
let localStorage: LocalStorage = new LocalStorage(para);
export default class EntryAbility extends UIAbility {
storage: LocalStorage = localStorage

onWindowStageCreate(windowStage: window.WindowStage) {
windowStage.loadContent('pages/Index', this.storage);
}
}

// 通过getShared接口获取stage共享的LocalStorage实例
let storage = LocalStorage.getShared()

@Entry(storage)
@Component
struct CompA {
  // can access LocalStorage instance using 
  // @LocalStorageLink/Prop decorated variables
  @LocalStorageLink('PropA') varA: number = 1;

  build() {
    Column() {
      Text(`${this.varA}`).fontSize(50)
    }
  }
}