Extension of Volley's NetworkImageView that fades in images as they're loaded

FadeInNetworkImageView.java

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.drawable.*;
import android.util.AttributeSet;

import com.android.volley.toolbox.NetworkImageView;

public class FadeInNetworkImageView extends NetworkImageView {

    private static final int FADE_IN_TIME_MS = 250;

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

    public FadeInNetworkImageView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public FadeInNetworkImageView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    public void setImageBitmap(Bitmap bm) {
        TransitionDrawable td = new TransitionDrawable(new Drawable[]{
                new ColorDrawable(android.R.color.transparent),
                new BitmapDrawable(getContext().getResources(), bm)
        });

        setImageDrawable(td);
        td.startTransition(FADE_IN_TIME_MS);
    }
}

For starters this will eliminate one "new".

private static ColorDrawable cd = new ColorDrawable(android.R.color.transparent);

and then

    TransitionDrawable td = new TransitionDrawable(new Drawable[]{
            cd,
            new BitmapDrawable(getContext().getResources(), bm)
    });

ColorDrawable can be replaced by getDrawable() if setDefaultImageResId() was called before.

Very useful! Is possible to remove the effect once that an image has been viewed? In a list of images the effect is annoying when scroll down and scroll up