如何在自定义下载器中使用glide

您需要为Glide编写定制的Model Loader。本节介绍如何编写自定义模型加载器。

class FileDataFetcher(
        private val model: File
) : DataFetcher<ByteBuffer> {
    override fun getDataClass(): Class<ByteBuffer> = ByteBuffer::class.java

    override fun cleanup() {
        TODO("cleanup data fetcher | run on background thread")
    }

    override fun getDataSource(): DataSource {
        TODO("return DataSource.LOCAL or DataSource.LOCAL OR DataSource.MEMORY_CACHE or DataSource.REMOTE based on your need")
    }

    override fun cancel() {
        TODO("cancel download request | run on main thread")
    }

    override fun loadData(priority: Priority, callback: DataFetcher.DataCallback<in ByteBuffer>) {
        TODO("start download or load in external storage | run on background thread")
    }
}

class FileModelLoader : ModelLoader<File, ByteBuffer> {

    override fun buildLoadData(model: File, width: Int, height: Int, options: Options): ModelLoader.LoadData<ByteBuffer>? =
            ModelLoader.LoadData(ObjectKey(model), FileDataFetcher(model))

    override fun handles(model: File): Boolean = model.exists()
}

class FileModelLoaderFactory : ModelLoaderFactory<File, ByteBuffer> {

    override fun build(multiFactory: MultiModelLoaderFactory): ModelLoader<File, ByteBuffer> = FileModelLoader()

    override fun teardown() = Unit
}

@GlideModule
class GlideAppModule : AppGlideModule() {
    override fun registerComponents(context: Context, glide: Glide, registry: Registry) {
        registry.prepend(File::class.java, ByteBuffer::class.java, FileModelLoaderFactory())
        super.registerComponents(context, glide, registry)
    }
}

当您File使用Glide加载时

Glide.with(mContext)
   .load(new File(path))
   .into(holder.mImagePreview);

Glide称您的模型加载器