fresco研究

SimpleDraweeView

  public void setImageURI(Uri uri, @Nullable Object callerContext) {
    DraweeController controller = mSimpleDraweeControllerBuilder
        .setCallerContext(callerContext)
        .setUri(uri)
        .setOldController(getController())
        .build();
    setController(controller);  ---->attachController--->subscribe

AbstractDraweeControllerBuilder

 buildController() {
    AbstractDraweeController controller = obtainController();

PipelineDraweeController

obtainController(){
....
newController(
          obtainDataSourceSupplier(),
          generateUniqueControllerId(),
          getCallerContext());
obtainDataSourceSupplier()

AbstractDraweeControllerBuilder

obtainDataSourceSupplier()
....
getDataSourceSupplierForRequest(imageRequest, /* bitmapCacheOnly */ false);

PipelineDraweeControllerBuilder

  protected DataSource<CloseableReference<CloseableImage>> getDataSourceForRequest(
      ImageRequest imageRequest,
      Object callerContext,
      boolean bitmapCacheOnly) {
    if (bitmapCacheOnly) {
      return mImagePipeline.fetchImageFromBitmapCache(imageRequest, callerContext);
    } else {
      return mImagePipeline.fetchDecodedImage(imageRequest, callerContext);
    }

ImagePipeline

submitFetchRequest

DecodeProducer

produceResults
.....
mJobScheduler.scheduleJob();