HarmonyOS 鸿蒙Next 如何将用户数据存储到文件管理里面

参考以下demo。首先通过Picker选择文件保存地址，再用uri保存该地址，再使用ohos.file.fs对文件进行读写。同理，你可以先获取文件保存地址后，再将数据存入。

import { common } from '@kit.AbilityKit';
import { picker } from '@kit.CoreFileKit';
import { BusinessError } from '@kit.BasicServicesKit';
import { fileIo as fs } from '@kit.CoreFileKit';

@Entry
@Component
struct Picker {
  @State message1: string = '点我新建文件';
  @State message2: string = '点我写入文件'
  @State uri: string = ''

  build() {
    Row() {
      Column() {
        Text(this.message1)
          .fontSize(30)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {
            let context = getContext(this) as common.Context; // 请确保getContext(this)返回结果为UIAbilityContext
            try {
              let documentSaveOptions = new picker.DocumentSaveOptions();
              documentSaveOptions.newFileNames = ['DocumentViewPicker01.txt'];
              let documentPicker = new picker.DocumentViewPicker(context);
              documentPicker.save(documentSaveOptions).then((documentSaveResult: Array<string>) => {
                this.uri = documentSaveResult[0];
                console.info('DocumentViewPicker.save successfully, documentSaveResult uri: ' + this.uri);
              }).catch((err: BusinessError) => {
                console.error('DocumentViewPicker.save failed with err: ' + JSON.stringify(err));
              });
              let file = fs.openSync(this.uri, fs.OpenMode.READ_WRITE);
              console.info('file fd: ' + file.fd);
              let writeLen: number = fs.writeSync(file.fd, 'hello, world');
              console.info('write data to file succeed and size is:' + writeLen);
              fs.closeSync(file);
            } catch (error) {
              let err: BusinessError = error as BusinessError;
              console.error('DocumentViewPicker failed with err: ' + JSON.stringify(err));
            }
          })
          .margin({bottom:23})
        Text(this.message2)
          .fontSize(30)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {
            let file = fs.openSync(this.uri, fs.OpenMode.READ_WRITE);
            console.info('file fd: ' + file.fd);
            let writeLen: number = fs.writeSync(file.fd, 'hello, world');
            console.info('write data to file succeed and size is:' + writeLen);
            fs.closeSync(file);
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}