鴻蒙開發過程中，經常會進行系統調用，拍照、拍視頻、選擇圖庫圖片、選擇圖庫視頻、選擇文件。今天就給大家分享一個工具類。

1.話不多說，先展示樣式

2.設計思路

根據官方提供的指南開發工具類，基礎的拍照、拍視頻、圖庫選照片、選文件不過多綴述，圖庫選擇這里設計成集合形式，可返回圖片和視頻，視頻展示時不顯示內容，所以在工具類多加了一個獲取視頻縮略圖的功能。

![搜狗高速瀏覽器截圖20240326151450.png](//file1.elecfans.com/web2/M00/C5/D1/wKgZomYChGOAUaiiAADe1d8SeRY102.jpg)

**3.具體代碼**

import common from '@ohos.app.ability.common';
import picker from '@ohos.file.picker';
import mediaLibrary from '@ohos.multimedia.mediaLibrary';
import wantConstant from '@ohos.ability.wantConstant';
import { MediaBean } from '../bean/MediaBean';
import { StringUtils } from '../utils/StringUtils';

/**

• @description 多媒體輔助類
• @author Gwei
• @time 2024/3/1 15:57
  */
  export class MediaHelper {
  private readonly TAG: string = 'MediaHelper';

private mContext: common.Context;

constructor(context: common.Context) {
this.mContext = context;
}

/**

• 圖庫選擇,返回最大數量為9的圖片、視頻集合
  */
  public selectPicture(count:number): Promise< Array< MediaBean >> {

let imgList:Array< string > = [];
let mediaList:Array< MediaBean > = [];
try {
  let photoSelectOptions = new picker.PhotoSelectOptions();
  photoSelectOptions.MIMEType = picker.PhotoViewMIMETypes.IMAGE_TYPE;
  photoSelectOptions.maxSelectNumber = 9-count;
  let photoPicker = new picker.PhotoViewPicker();
  return photoPicker.select(photoSelectOptions)
    .then((photoSelectResult) = > {
      //Log.info(this.TAG, 'PhotoViewPicker.select successfully, PhotoSelectResult uri: ' + JSON.stringify(photoSelectResult));

      if (photoSelectResult && photoSelectResult.photoUris && photoSelectResult.photoUris.length > 0) {

        for (let i = 0; i < photoSelectResult.photoUris.length; i++) {
          imgList.push(photoSelectResult.photoUris[i]);
        }
        //Log.info(this.TAG, 'PhotoViewPicker.select successfully, PhotoSelectResult uri: ' + filePath);
        return imgList;
      }

    }).catch((err) = > {
      //Log.error(this.TAG, 'PhotoViewPicker.select failed with err: ' + err);
      return err;
    }).then(async (imgList) = > {
      for (let index = 0; index < imgList.length; index++) {
        const mediaBean = await this.buildMediaBean(imgList[index]);
        mediaList.push(mediaBean);
      }
      return mediaList;
    });
} catch (err) {
  //Log.error(this.TAG, 'PhotoViewPicker failed with err: ' + err);
  return Promise.reject(err);
}

}

/**

• 選擇文件
  */
  public selectFile(): Promise< MediaBean > {
  try {
  let documentSelectOptions = new picker.DocumentSelectOptions();
  let documentPicker = new picker.DocumentViewPicker();
  return documentPicker.select(documentSelectOptions)
  .then((documentSelectResult) = > {
  //Log.info(this.TAG, 'DocumentViewPicker.select successfully, DocumentSelectResult uri: ' + JSON.stringify(documentSelectResult));

   if (documentSelectResult && documentSelectResult.length > 0) {
     let filePath = documentSelectResult[0];
     //Log.info(this.TAG, 'DocumentViewPicker.select successfully, DocumentSelectResult uri: ' + filePath);
     return filePath;
   }
  

  }).catch((err) = > {
  //Log.error(this.TAG, 'PhotoViewPicker.select failed with err: ' + err);
  return err;
  }).then(async (filePath) = > {

   const mediaBean = await this.buildMediaBean(filePath);
   return mediaBean;
  

  });
  } catch (err) {
  //Log.error(this.TAG, 'PhotoViewPicker failed with err: ' + err);
  return Promise.reject(err);
  }
  }

/**

• 拍照
  */
  public async takePhoto(context: common.UIAbilityContext): Promise< MediaBean > {

let want = {
  'uri': '',
  'action': wantConstant.Action.ACTION_IMAGE_CAPTURE,
  'parameters': {},
};
return context.startAbilityForResult(want)
  .then((result) = > {
    //Log.info(this.TAG, `startAbility call back , ${JSON.stringify(result)}`);
    if (result.resultCode === 0 && result.want && StringUtils.isNotNullOrEmpty(result.want.uri)) {
      //拍照成功
      //Log.info(this.TAG, 'takePhoto successfully, takePhotoResult uri: ' + result.want.uri);
      return result.want.uri;
    }
  }).catch((error) = > {
    //Log.info(this.TAG, `startAbility error , ${JSON.stringify(error)}`);
    return error;
  }).then(async (uri: string) = > {
    const mediaBean = await this.buildMediaBean(uri);
    return mediaBean;
  });

}

/**

• 拍視頻
  */
  public async takeVideo(context: common.UIAbilityContext): Promise< MediaBean > {

let want = {
  'uri': '',
  'action': wantConstant.Action.ACTION_VIDEO_CAPTURE,
  'parameters': {},
};
return context.startAbilityForResult(want)
  .then((result) = > {
    //Log.info(this.TAG, `startAbility call back , ${JSON.stringify(result)}`);
    if (result.resultCode === 0 && result.want && StringUtils.isNotNullOrEmpty(result.want.uri)) {
      //拍照成功
      //Log.info(this.TAG, 'takePhoto successfully, takePhotoResult uri: ' + result.want.uri);
      return result.want.uri;
    }
  }).catch((error) = > {
    //Log.info(this.TAG, `startAbility error , ${JSON.stringify(error)}`);
    return error;
  }).then(async (uri: string) = > {
    const mediaBean = await this.buildMediaBean(uri);
    return mediaBean;
  });

}

/**

• 封裝多媒體實體類
• @param uri 文件路徑
  */
  private async buildMediaBean(uri: string): Promise< MediaBean > {

if (StringUtils.isNullOrEmpty(uri)) {
  return null;
}

const mediaBean: MediaBean = new MediaBean();
mediaBean.localUrl = uri;
await this.appendFileInfoToMediaBean(mediaBean, uri);
return mediaBean;

}

/**

• 通過Uri查找所選文件信息，插入到MediaBean中
• @param mediaBean
• @param uri
  */
  private async appendFileInfoToMediaBean(mediaBean: MediaBean, uri: string):Promise< MediaBean > {

if (StringUtils.isNullOrEmpty(uri)) {
  return;
}
let fileList: Array< mediaLibrary.FileAsset > = [];

const parts: string[] = uri.split('/');
const id: string = parts.length > 0 ? parts[parts.length - 1] : '-1';

try {

  let media = mediaLibrary.getMediaLibrary(this.mContext);
  let mediaFetchOptions: mediaLibrary.MediaFetchOptions = {
    selections: mediaLibrary.FileKey.ID + '= ?',
    selectionArgs: [id],
    uri: uri
  };

  let fetchFileResult = await media.getFileAssets(mediaFetchOptions);
  //Log.info(this.TAG, `fileList getFileAssetsFromType fetchFileResult.count = ${fetchFileResult.getCount()}`);
  fileList = await fetchFileResult.getAllObject();
  fetchFileResult.close();
  await media.release();

} catch (e) {
  //Log.error(this.TAG, "query: file data  exception ");
}

if (fileList && fileList.length > 0) {

  let fileInfoObj = fileList[0];
  //Log.info(this.TAG, `file id = ${JSON.stringify(fileInfoObj.id)} , uri = ${JSON.stringify(fileInfoObj.uri)}`);
  //Log.info(this.TAG, `file fileList displayName = ${fileInfoObj.displayName} ,size = ${fileInfoObj.size} ,mimeType = ${fileInfoObj.mimeType}`);

  mediaBean.fileName = fileInfoObj.displayName;
  mediaBean.fileSize = fileInfoObj.size;
  mediaBean.fileType = fileInfoObj.mimeType;
  mediaBean.pixelmap = await this.getPixelmap(fileInfoObj)
}

}

/**

• @description 獲取縮略圖
• @author Gwei
• @time 2024/3/1 15:57
  */
  getPixelmap(fileInfoObj) {
  return new Promise(function (resolve, reject) {
  fileInfoObj.getThumbnail((err, pixelmap) = > {
  if (!err) {
  resolve(pixelmap)
  }else{
  resolve('');
  }
  })
  })
  }
  }

**4.使用方法**

async handleClick(option: MediaOption) {
let mediaBean: MediaBean;
switch (option) {
case MediaOption.TakePhoto:
mediaBean = await this.mediaHelper.takePhoto(getContext() as common.UIAbilityContext);
this.imgList.push(mediaBean)
break;
case MediaOption.TakeVideo:
mediaBean = await this.mediaHelper.takeVideo(getContext() as common.UIAbilityContext);
this.imgList.push(mediaBean)
break;
case MediaOption.Picture:
let list: Array< MediaBean > = [];
list = await this.mediaHelper.selectPicture(this.imgList.length);
for (let i = 0; i < list.length; i++) {
this.imgList.push(list[i])
}
break;
case MediaOption.File:
mediaBean = await this.mediaHelper.selectFile();
this.audioList.push(mediaBean);
break;
default:
break;
}
}

工具類已經提供給大家了，希望能幫助到大家！！！

審核編輯 黃宇