有人知道HarmonyOS Next当访问网络图片uri时，是否有保存网络图片的API吗 ？

Question

如题：HarmonyOS 当访问网络图片uri时，是否有保存网络图片的API

Answer 1

需要先使用http的request方式，下载文件。再将文件转成pixelMap的arrayBuffer，最后使用photoAccessHelper.getPhotoAccessHelper提供的访问相册接口，将文件存入本地

import { BusinessError, request, zlib } from '@kit.BasicServicesKit'; 
import { abilityAccessCtrl, common, Permissions } from '@kit.AbilityKit'; 
import fs from '@ohos.file.fs'; 
import { image } from '@kit.ImageKit'; 
import { photoAccessHelper } from '@kit.MediaLibraryKit'; 
import { http } from '@kit.NetworkKit'; 
import { promptAction } from '@kit.ArkUI'; 
import ResponseCode from '@ohos.net.http'; 
import { picker } from '@kit.CoreFileKit'; 
 
 
let context = getContext(this) as common.UIAbilityContext; 
let filesDir = context.filesDir 
const PERMISSIONS: Array<Permissions> = [ 
  'ohos.permission.READ_MEDIA', 
  'ohos.permission.WRITE_MEDIA' 
]; 
 
@Entry 
@Component 
struct Index { 
  @State image: PixelMap | undefined = undefined; 
  @State photoAccessHelper: photoAccessHelper.PhotoAccessHelper | undefined = undefined; // 相册模块管理实例 
  @State imageBuffer: ArrayBuffer | undefined = undefined; // 图片ArrayBuffer 
 
  /** 
   * 通过http的request方法从网络下载图片资源 
   */ 
  async getPicture() { 
    http.createHttp() 
      .request('https://xxx.com/harmonyos-cases/cases/raw/master/CommonAppDevelopment/feature/variablewatch/src/main/resources/base/media/grape.png', 
        (error: BusinessError, data: http.HttpResponse) => { 
          if (error) { 
            // 下载失败时弹窗提示检查网络，不执行后续逻辑 
            console.info("error") 
            return; 
          } 
          this.transcodePixelMap(data); 
          // 判断网络获取到的资源是否为ArrayBuffer类型 
          if (data.result instanceof ArrayBuffer) { 
            this.imageBuffer = data.result as ArrayBuffer; 
          } 
        } 
      ) 
  } 
 
  /** 
   * 使用createPixelMap将ArrayBuffer类型的图片装换为PixelMap类型 
   * @param data：网络获取到的资源 
   */ 
  transcodePixelMap(data: http.HttpResponse) { 
    if (ResponseCode.ResponseCode.OK === data.responseCode) { 
      const imageData: ArrayBuffer = data.result as ArrayBuffer; 
      // 通过ArrayBuffer创建图片源实例。 
      const imageSource: image.ImageSource = image.createImageSource(imageData); 
      const options: image.InitializationOptions = { 
        'alphaType': 0, // 透明度 
        'editable': false, 
        'pixelFormat': 3, // 像素格式 
        'scaleMode': 1, // 缩略值 
        'size': { height: 100, width: 100 } 
      }; // 创建图片大小 
 
      // 通过属性创建PixelMap 
      imageSource.createPixelMap(options).then((pixelMap: PixelMap) => { 
        this.image = pixelMap; 
      }); 
    } 
  } 
 
  /** 
   * 保存ArrayBuffer到图库 
   * @param buffer：图片ArrayBuffer 
   * @returns 
   */ 
  async saveImage(buffer: ArrayBuffer | string): Promise<void> { 
    const context = getContext(this) as common.UIAbilityContext; // 获取getPhotoAccessHelper需要的context 
    const helper = photoAccessHelper.getPhotoAccessHelper(context); // 获取相册管理模块的实例 
    const uri = await helper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg'); // 指定待创建的文件类型、后缀和创建选项，创建图片或视频资源 
    const file = await fs.open(uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE); 
    await fs.write(file.fd, buffer); 
    await fs.close(file.fd); 
  } 
 
  /** 
   * 保存ArrayBuffer到用户选择的路径 
   * @param buffer：图片ArrayBuffer 
   * @returns 
   */ 
  async pickerSave(buffer: ArrayBuffer | string): Promise<void> { 
    const photoSaveOptions = new picker.PhotoSaveOptions(); // 创建文件管理器保存选项实例 
    photoSaveOptions.newFileNames = ['PhotoViewPicker ' + new Date().getTime() + '.jpg']; // 保存文件名（可选） 
    const photoViewPicker = new picker.PhotoViewPicker; 
    photoViewPicker.save(photoSaveOptions) 
      .then(async (photoSvaeResult) => { 
        const uri = photoSvaeResult[0]; 
        const file = await fs.open(uri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE); 
        await fs.write(file.fd, buffer); 
        await fs.close(file.fd); 
        promptAction.showToast({ 
          message: "save", 
          duration: 2000 
        }) 
      }); 
  } 
 
  async aboutToAppear(): Promise<void> { 
    const context = getContext(this) as common.UIAbilityContext; 
    const atManager = abilityAccessCtrl.createAtManager(); 
    await atManager.requestPermissionsFromUser(context, PERMISSIONS); 
    this.getPicture(); 
  } 
 
  build() { 
    Column() { 
      Column() { 
        Text('title') 
          .fontSize(14) 
          .fontWeight(FontWeight.Me) 
          .margin({ bottom: 40}) 
        Text('content') 
      } 
      .backgroundColor(Color.White) 
      .borderRadius(14) 
      .padding(40) 
 
      Image(this.image) 
        .objectFit(ImageFit.Contain) 
        .width('50%') 
        .height(200) 
 
      SaveButton() 
        .width(200) 
        .onClick(async () => { 
          if (this.imageBuffer !== undefined) { 
            await this.saveImage(this.imageBuffer); 
            promptAction.showToast({ 
              message: 'success', 
              duration: 2000 
            }) 
          } 
        }) 
 
      Button('picker_save') 
        .margin({ top: 40 }) 
        .height(40) 
        .onClick(async () => { 
          if (this.imageBuffer !== undefined) { 
            this.pickerSave(this.imageBuffer); 
          } 
        }) 
    } 
    .height('100%') 
    .margin(40) 
  } 
}