HarmonyOS 如何获取手机上所有可访问目录下的PDF文件列表

请尝试以下代码是否满足您的需求：

import picker from '@ohos.file.picker';
import { BusinessError } from '@kit.BasicServicesKit';

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';

  DocSel() {
    let docSel = new picker.DocumentSelectOptions();
    let docPic = new picker.DocumentViewPicker();
    docSel.selectMode = picker.DocumentSelectMode.FILE;
    docSel.fileSuffixFilters = ['.pdf'];
    docPic.select(docSel).then((documentSelectResult: Array<string>) => {
      console.info('DocumentViewPicker.select successfully, documentSelectResult uri: ' + JSON.stringify(documentSelectResult));
    }).catch((err: BusinessError) => {
      console.error('DocumentViewPicker.select failed with err: ' + JSON.stringify(err));
    });
  }

  build() {
    RelativeContainer() {
      Button("test")
        .onClick(() => {
          this.DocSel()
        })
    }
    .height('100%')
    .width('100%')
  }
}