Android Studio Kotlin 将lifecycleScope.launchWhenCreated 从Fragment 移动到onBindViewHolder

如何解决Android Studio Kotlin 将lifecycleScope.launchWhenCreated 从Fragment 移动到onBindViewHolder

使用 Android Studio Kotlin 我有获取 flickr 图像的工作代码。当我获取超过几页的照片（即，每页获取 100 张照片大约 1 秒）时，此代码非常慢。我的 recycleView 中有大约 4000 个项目。理想情况下，我只想在查看器图像进入视图时获取照片，并在视图通过时取消。我想我希望从 ViewHolder onBindViewHolder 运行生命周期范围.launchWhenCreated。但是当我这样做时，生命周期范围不被识别为可编译。根据我的阅读，lifecycleScope 仅在片段的范围内。

问题是，如何让代码在 viewHolder 级别运行？

这是我的 Fragment 中的代码。

private lateinit var figurePhotoListRecyclerView: RecyclerView
private val photosViewModel: PhotosViewModel by viewModels()

...

lifecycleScope.launchWhenCreated {

            // list of all photos
            val fullImageList = mutableListOf<FlickrPhoto>()

            // if all figures,just get the primary front images
                    figureListForSeries.forEach { figure ->
                        if (figure.flickrPrimaryPhoto == null) {

                            val figureImageName = "${figure.figureGlobalUniqueId}_$PRIMARY_FRONT_IMAGE_TEXT"

                            val pageCounter = 1
                            val imageList: MutableList<FlickrPhoto> =
                                photosViewModel.fetchImagesText(
                                    figureImageName,pageCounter.toString()
                                ) as MutableList<FlickrPhoto>

                            fullImageList.addAll(imageList)

                            // set photo to figure contains figureId and not counterfeit
                            figure.flickrPrimaryPhoto =
                                fullImageList.firstOrNull { primaryImage ->
                                    primaryImage.title == figureImageName
                                }
                        }

                        figurePhotoListRecyclerView.adapter?.notifyDataSetChanged()
                    }
                

            figurePhotoListRecyclerView.adapter?.notifyDataSetChanged()
        }

我想在viewHolder中运行这里的代码

    override fun onBindViewHolder(holder: FigurePhotoListViewHolder,position: Int) {
    // get the series for the position
    val figure = figureFilterList[position]

    // click listener
    holder.itemView.setOnClickListener {
        clickListener.figureClicked(figure)
    }

    // set photo
    if (figure.flickrPrimaryPhoto != null) {
        holder.bind(figure.flickrPrimaryPhoto!!)
    }
    else {

        <------ run the photolookup here! ------->

        holder.imageViewFigure.setImageResource(R.drawable.mytoybox_logo)
    }

...

来自 https://medium.com/@yoavgray/mvvm-flickr-android-app-with-common-dev-use-cases-part-3-6586133321b6 的 Flickr 照片代码

class PhotosViewModel : ViewModel() {
private val mutablePhotosLiveData = MutableLiveData<List<FlickrPhoto>>()
val photosLiveData: LiveData<List<FlickrPhoto>> = mutablePhotosLiveData

suspend fun fetchImagesText(searchText: String,page: String): List<FlickrPhoto> {
    if (searchText.isBlank()) {
        return emptyList()
    }
    val searchResponse = WebClient.clientText.fetchImages(searchText,page)
    return searchResponse.photos.photo.map { photo ->
        FlickrPhoto(
            id = photo.id,url = "https://farm${photo.farm}.staticflickr.com/${photo.server}/${photo.id}_${photo.secret}.jpg",title = photo.title
        )
    }
}
}

get 调用 https://medium.com/@yoavgray/mvvm-flickr-android-app-with-common-dev-use-cases-part-3-6586133321b6

interface FlickrAPIServiceText {
companion object {
    const val FLICKR_API_KEY: String = "xxx"
    const val FLICKR_USER_ID: String = "yyy"
}

    @GET("?method=flickr.photos.search&format=json&nojsoncallback=1&extras=original_format&user_id=$FLICKR_USER_ID&api_key=$FLICKR_API_KEY")
    suspend fun fetchImages(
        @Query("text") text: String,@Query("page") page: String): PhotosSearchResponse
}

来自 https://medium.com/@yoavgray/mvvm-flickr-android-app-with-common-dev-use-cases-part-3-6586133321b6 的 Web 客户端实用程序

// Retrofit's base urls must end with a "/" or OkHttp will through an exception!
private const val BASE_URL = "https://api.flickr.com/services/rest/"
private const val CONNECTION_TIMEOUT_MS: Long = 10

object WebClient {

val clientText: FlickrAPIServiceText by lazy {
    Retrofit.Builder().baseUrl(BASE_URL)
        .addConverterFactory(
            GsonConverterFactory.create(
                GsonBuilder()
                    .setFieldNamingPolicy(FieldNamingPolicy.LOWER_CASE_WITH_UNDERSCORES)
                    .create()
            )
        )
        .client(
            OkHttpClient.Builder().connectTimeout(
                CONNECTION_TIMEOUT_MS,TimeUnit.SECONDS
            ).addInterceptor(HttpLoggingInterceptor().apply {
                level = HttpLoggingInterceptor.Level.BASIC
            }).build()
        )
        .build()
        .create(FlickrAPIServiceText::class.java)
}
}