【HarmonyOS】鸿蒙保存图片或视频到相册

前言

鸿蒙中保存图片或者视频，或者其他媒体文件到设备的媒体库，可以是相册，也可以是文件管理等。共有两种方式：

需要应用申请受限权限，获取文件读写的权限（调用需要ohos.permission.READ_IMAGEVIDEO和ohos.permission.WRITE_IMAGEVIDEO的权限），这样就可以将媒体资源（图片or视频or等等）保存到媒体库。
通过安全控件，用户触发后表示同意，可以临时授权给应用就行保存处理。

关于第二种安全控件，又分为saveButton保存按钮 和showAssetsCreationDialog授权弹框两种形式。前者的按钮样式不能自定义，所以后者以弹框的形式，让用户操作，触发入口的样式，应用就可以自定义了。后者算是前者的一种替代补充。

一、保存图片和视频授权示例

需要申请"ohos.permission.READ_IMAGEVIDEO"和"ohos.permission.WRITE_IMAGEVIDEO"权限。该权限是管制权限，需要你的应用去通过场景申请【申请使用受限权限】

配置权限READ_IMAGEVIDEO，WRITE_IMAGEVIDEO

dart 复制代码

"requestPermissions": [
  {
    "name": "ohos.permission.READ_IMAGEVIDEO",
    "usedScene": {
      "abilities": [
        "EntryAbility"
      ],
      "when": "inuse"
    },
    "reason": "$string:CAMERA"
  },
  {
    "name": "ohos.permission.WRITE_IMAGEVIDEO",
    "usedScene": {
      "abilities": [
        "EntryAbility"
      ],
      "when": "inuse"
    },
    "reason": "$string:CAMERA"
  }
]

向用户申请权限

dart 复制代码

  //  创建申请权限明细
  async reqPermissionsFromUser(): Promise<number[]> {
    let context = getContext() as common.UIAbilityContext;
    let atManager = abilityAccessCtrl.createAtManager();
    let grantStatus = await atManager.requestPermissionsFromUser(context, ['ohos.permission.READ_IMAGEVIDEO','ohos.permission.WRITE_IMAGEVIDEO']);
    return grantStatus.authResults;
  }

  // 用户申请权限
  async requestPermission() {
    let grantStatus = await this.reqPermissionsFromUser();
    for (let i = 0; i < grantStatus.length; i++) {
      if (grantStatus[i] === 0) {
        // 用户授权，可以继续访问目标操作



      }
    }
  }

保存图片到媒体库

dart 复制代码

public async savePicture(buffer: ArrayBuffer): Promise<void> {
  let helper : photoAccessHelper.PhotoAccessHelper = photoAccessHelper.getPhotoAccessHelper(getContext(this) as common.UIAbilityContext);
  let options: photoAccessHelper.CreateOptions = {
    title: Date.now().toString()
  };
  let photoUri: string = await helper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg', options);
  console.info(photoUri)
  // createAsset的调用需要ohos.permission.READ_IMAGEVIDEO和ohos.permission.WRITE_IMAGEVIDEO的权限
  let file: fs.File = fs.openSync(photoUri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
  await fs.write(file.fd, buffer);
  fs.closeSync(file);
}

二、saveButton示例

dart 复制代码

import { photoAccessHelper } from '@kit.MediaLibraryKit';

@Entry
@Component
struct saveButtonExample {
    saveButtonOptions: SaveButtonOptions = {
    icon: SaveIconStyle.FULL_FILLED,
    text: SaveDescription.SAVE_IMAGE,
    buttonType: ButtonType.Capsule
  } // 设置安全控件按钮属性

  build() {
    Row() {
      Column() {
        SaveButton(this.saveButtonOptions) // 创建安全控件按钮
          .onClick(async (event, result: SaveButtonOnClickResult) => {
             if (result == SaveButtonOnClickResult.SUCCESS) {
               try {
                 let context = getContext();
                 let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
                 // 需要确保fileUri对应的资源存在
                 let fileUri = 'file://com.example.temptest/data/storage/el2/base/haps/entry/files/test.jpg';
                 let assetChangeRequest: photoAccessHelper.MediaAssetChangeRequest = photoAccessHelper.MediaAssetChangeRequest.createImageAssetRequest(context, fileUri);
                 await phAccessHelper.applyChanges(assetChangeRequest);
                 console.info('createAsset successfully, uri: ' + assetChangeRequest.getAsset().uri);
               } catch (err) {
                 console.error(`create asset failed with error: ${err.code}, ${err.message}`);
               }
             } else {
               console.error('SaveButtonOnClickResult create asset failed');
             }
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}

三、 showAssetsCreationDialog示例

dart 复制代码

import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { fileIo } from '@kit.CoreFileKit';

let context = getContext(this);
let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);

async function showAssetsCreationDialogExample() {
  try {
    // 指定待保存到媒体库的位于应用沙箱的图片uri
    let srcFileUri = 'file://com.example.temptest/data/storage/el2/base/haps/entry/files/test.jpg';
    let srcFileUris: Array<string> = [
      srcFileUri
    ];
    // 指定待保存照片的创建选项，包括文件后缀和照片类型，标题和照片子类型可选
    let photoCreationConfigs: Array<photoAccessHelper.PhotoCreationConfig> = [
      {
        title: 'test', // 可选
        fileNameExtension: 'jpg',
        photoType: photoAccessHelper.PhotoType.IMAGE,
        subtype: photoAccessHelper.PhotoSubtype.DEFAULT, // 可选
      }
    ];
    // 基于弹窗授权的方式获取媒体库的目标uri
    let desFileUris: Array<string> = await phAccessHelper.showAssetsCreationDialog(srcFileUris, photoCreationConfigs);
    // 将来源于应用沙箱的照片内容写入媒体库的目标uri
    let desFile: fileIo.File = await fileIo.open(desFileUris[0], fileIo.OpenMode.WRITE_ONLY);
    let srcFile: fileIo.File = await fileIo.open(srcFileUri, fileIo.OpenMode.READ_ONLY);
    await fileIo.copyFile(srcFile.fd, desFile.fd);
    fileIo.closeSync(srcFile);
    fileIo.closeSync(desFile);
    console.info('create asset by dialog successfully');
  } catch (err) {
    console.error(`failed to create asset by dialog successfully errCode is: ${err.code}, ${err.message}`);
  }
}

注意：
1. 使用createAsset需要指定是视频还是图片， fileio.open并不校验文件内容
2. 使用createImageAssetRequest接口，如果要保存视频需要用createVideoeAssetRequest
或者还可以直接使用createAssetRequest和addResource的方式

【HarmonyOS】 鸿蒙保存图片或视频到相册