1. 导入库

在build.gradle中添加glide库，kotlin用kapt，java用annotationProcessor

dependencies {
    implementation 'com.github.bumptech.glide:glide:4.13.2'
    kapt 'com.github.bumptech.glide:compiler:4.13.2'
    annotationProcessor 'com.github.bumptech.glide:compiler:4.13.2'
}

ProjectGlideModule继承AppGlideModule，需要添加GlideModule注释。applyOptions方法中可以对builder进行全局配置。

@GlideModule
class ProjectGlideModule : AppGlideModule() {

    override fun applyOptions(context: Context, builder: GlideBuilder) {
        super.applyOptions(context, builder)
    }

    override fun registerComponents(context: Context, glide: Glide, registry: Registry) {
        super.registerComponents(context, glide, registry)
    }
    
}

2. OKHttp配置

Glide 默认的请求网络框架是HttpURLConnection，想要改成OkHttp就需要用到registerComponents函数。首先需要导入okhttp3-integration库

implementation 'com.github.bumptech.glide:okhttp3-integration:4.13.2'

在registerComponents函数内调用Registry的replace方法替代网络请求框架。

override fun registerComponents(context: Context, glide: Glide, registry: Registry) {
    super.registerComponents(context, glide, registry)

    registry.replace(GlideUrl::class.java, InputStream::class.java, OkHttpUrlLoader.Factory(NetworkUtil.getOKHttpClient()))
}

3. 自定义模型

在实际项目中，我们往往会有一些特殊需要。比如我们通过url返回图片的字节流，还需要Base64解码才能使用。

• 定义GlideDownloadPic类，继承com.bumptech.glide.load.Key，需要实现updateDiskCacheKey函数

  class GlideDownloadPic(val picUrl: String) : Key {
      private var mGlideUrl = GlideUrl(picUrl)
  
      override fun updateDiskCacheKey(messageDigest: MessageDigest) {
          mGlideUrl.updateDiskCacheKey(messageDigest)
      }
  
  }
  

• 定义GlideDownloadPicModelLoader，继承ModelLoader。Factory继承ModelLoaderFactory，在后面注册时使用。buildLoadData函数用来获取图片数据。

  class GlideDownloadPicModelLoader : ModelLoader<GlideDownloadPic, InputStream> {
  
      class Factory : ModelLoaderFactory<GlideDownloadPic, InputStream> {
  
          override fun build(multiFactory: MultiModelLoaderFactory): ModelLoader<GlideDownloadPic, InputStream> {
              return GlideDownloadPicModelLoader()
          }
  
          override fun teardown() {
          }
  
      }
  
      override fun buildLoadData(
          model: GlideDownloadPic,
          width: Int,
          height: Int,
          options: Options
      ): ModelLoader.LoadData<InputStream>? {
          return ModelLoader.LoadData(model, GlideDownloadPicDataFetcher(model))
      }
  
      override fun handles(model: GlideDownloadPic): Boolean {
          return true
      }
  
  }
  

• 定义GlideDownloadPicDataFetcher，继承DataFetcher

  class GlideDownloadPicDataFetcher(downloadPic: GlideDownloadPic) : DataFetcher<InputStream> {
  
      private var mDownloadPic = downloadPic
  
      override fun loadData(priority: Priority, callback: DataFetcher.DataCallback<in InputStream>) {
          downloadPic(mDownloadPic.picUrl, {
              callback.onDataReady(ByteArrayInputStream(Base64.decode(it, Base64.DEFAULT)))
          }, {
              callback.onLoadFailed(it)
          })
      }
  
      // 下载图片
      private fun downloadPic(picUrl: String, onSuccess:(ByteArray) -> Unit, onFail:(Exception) -> Unit) {
          if (picUrl.startsWith("http")) {
              NetworkUtil.getOKHttpClient()
                  .newCall(Request.Builder().url(picUrl).build())
                  .enqueue(object : Callback{
                      override fun onResponse(call: Call, response: Response) {
                          if (response.isSuccessful) {
                              var bodyByteArray = response.body()?.bytes()
                              if (bodyByteArray != null) {
                                  onSuccess(bodyByteArray)
                                  return
                              }
                          }
                          onFail(IOException("wrong url $picUrl"))
                      }
  
                      override fun onFailure(call: Call, e: IOException) {
                          onFail(IOException("wrong url $picUrl"))
                      }
                  })
          } else {
              onFail(IOException("wrong url $picUrl"))
          }
      }
  
      override fun getDataClass(): Class<InputStream> {
          return InputStream::class.java
      }
  
      override fun cleanup() {
      }
  
      override fun getDataSource(): DataSource {
          return DataSource.REMOTE
      }
  
      override fun cancel() {
      }
  }
  

• 在registerComponents函数内注册

  registry.replace(GlideDownloadPic::class.java, InputStream::class.java,
          GlideDownloadPicModelLoader.Factory())
  

• 使用自定义模型

  Glide.with(this).load(GlideDownloadPic("xxx.jpg"))
          .error(getDrawable(R.drawable.xxx))
          .into(findViewById(R.id.image_view))
  

源码下载: https://github.com/nai-chen/AndroidBlog