Android Fresco图片加载优化的方案

<com.facebook.drawee.view.SimpleDraweeView
  android:id="@+id/simple_drawee_view"
  android:layout_width="480dp"
  android:layout_height="270dp"
  android:layout_alignParentBottom="true"
  android:layout_centerHorizontal="true"
  app:layout_constraintBottom_toBottomOf="parent"
  app:layout_constraintLeft_toLeftOf="parent"
  app:layout_constraintRight_toRightOf="parent"
  app:layout_constraintTop_toTopOf="parent" />

val mImageUrl = "https://static.runoob.com/images/demo/demo4.jpg"
val simple_drawee_view = findViewById<SimpleDraweeView>(R.id.simple_drawee_view)
simple_drawee_view.setImageURI(mImageUrl)

ImageRequest request = ImageRequestBuilder.newBuilderWithSource(uri)
 .setResizeOptions(new ResizeOptions(width, height))
 .build();
PipelineDraweeController controller = Fresco.newDraweeControllerBuilder()
 .setOldController(mDraweeView.getController())
 .setImageRequest(request)
 .build();
mSimpleDraweeView.setController(controller);

.setDownsampleEnabled(true)

public class DesiredSimpleDraweeView extends SimpleDraweeView {

 Uri mUri;
 Object mCallerContext;

 public DesiredSimpleDraweeView(Context context) {
  super(context);
 }

 @Override
 public void setImageURI(Uri uri, Object callerContext) {
  mUri = uri;
  mCallerContext = callerContext;
 }

 private void setImageURI(int width, int height) {
  try {
   ImageRequest imageRequest = ImageRequestBuilder.newBuilderWithSource(mUri)
     .setResizeOptions(new ResizeOptions(width, height))
     .build();
   DraweeController controller =
     getControllerBuilder()
       .setOldController(getController())
       .setImageRequest(imageRequest)
       .build();
   setController(controller);
  } catch (Exception ex) {
   ex.printStackTrace();
  }
 }

 @Override
 public void onWindowFocusChanged(boolean hasWindowFocus) {
  super.onWindowFocusChanged(hasWindowFocus);
  if (hasWindowFocus) {
   setImageURI(getWidth(), getHeight());
  }
 }
}