HarmonyOS @ohos.data.preferences 数据处理

import dataPreferences from '@ohos.data.preferences'; 
import { BusinessError } from '@kit.BasicServicesKit'; 
import { util } from '@kit.ArkTS'; 
 
 
let context: Context = getContext(this) 
 
 
function creatUuid(): string { 
  let rand = util.generateRandomUUID(true) 
  console.info(`UUID IS:` + rand) 
  return rand 
} 
 
function T() { 
  let preferences: dataPreferences.Preferences | null = null; 
  dataPreferences.getPreferences(context, 'myStore', (err: BusinessError, val: dataPreferences.Preferences) => { 
    if (err) { 
      console.error("Failed to get preferences. code =" + err.code + ", message =" + err.message); 
      return; 
    } 
    preferences = val; 
    console.info("Succeeded in getting preferences."); 
    let uuid: string = creatUuid() 
    preferences.put('startup', uuid, (err: BusinessError) => { 
      if (err) { 
        console.error("Failed to put value of 'startup'. code =" + err.code + ", message =" + err.message); 
        return; 
      } 
      preferences?.flush() 
      console.info("Succeeded in putting value of 'startup'."); 
    }) 
  }) 
} 
 
function T1() { 
  let preferences: dataPreferences.Preferences | null = null; 
  dataPreferences.getPreferences(context, 'myStore', (err: BusinessError, val: dataPreferences.Preferences) => { 
    if (err) { 
      console.error("Failed to get preferences. code =" + err.code + ", message =" + err.message); 
      return; 
    } 
    preferences = val; 
    console.info("Succeeded in getting preferences."); 
    preferences.get('startup', -1, (err: BusinessError, val: dataPreferences.ValueType) => { 
      if (err) { 
        console.error("Failed to get value of 'startup'. code =" + err.code + ", message =" + err.message); 
        return; 
      } 
      console.info("Succeeded in getting value of 'startup'. val： " + val); 
      if (typeof (val) == "string") { 
        console.info("val is string") 
      } else { 
        console.info("val is not string") 
      } 
    }) 
  }) 
} 
 
 
@Entry 
@Component 
struct Index { 
  @State message: string = 'Hello World'; 
 
  build() { 
    Row() { 
      Column() { 
        Text(this.message) 
          .fontSize(50) 
          .fontWeight(FontWeight.Bold) 
 
        Button("添加数据").onClick((event: ClickEvent) => { 
          T() 
        }) 
 
        Button("取出数据").onClick((event: ClickEvent) => { 
          T1() 
        }) 
      } 
      .width('100%') 
    } 
    .height('100%') 
  } 
}
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