add background image to android ListView using Picasso

Question

I need to add a background image to a ListView. Normally I would call listview.setBackground(myImage). But the image is coming from server and so I need to use Picasso to load the image into the background of my ListView. How do I do that?

Generosity

Answer 1

Option One

Define an anonymous subclass of com.squareup.picasso.Target

Picasso.with(yourContext)
      .load(yourImageUri)
      .into(new Target() {
        @Override
        @TargetApi(16)
        public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
            int sdk = android.os.Build.VERSION.SDK_INT;
            if(sdk < android.os.Build.VERSION_CODES.JELLY_BEAN) {
                yourListView.setBackgroundDrawable(new BitmapDrawable(bitmap));
            } else {
                yourListView.setBackground(new BitmapDrawable(getResources(), bitmap));
            }
        }

        @Override
        public void onBitmapFailed(Drawable errorDrawable) {
            // use error drawable if desired
        }

        @Override
        public void onPrepareLoad(Drawable placeHolderDrawable) {
            // use placeholder drawable if desired
        }
    });

Option Two

Subclass ListView and implement com.squareup.picasso.Target

public class PicassoListView extends ListView implements Target {

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

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

    @Override
    @TargetApi(16)
    public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
        int sdk = android.os.Build.VERSION.SDK_INT;
        if(sdk < android.os.Build.VERSION_CODES.JELLY_BEAN) {
            setBackgroundDrawable(new BitmapDrawable(bitmap));
        } else {
            setBackground(new BitmapDrawable(getResources(), bitmap));
        }
    }

    @Override
    public void onBitmapFailed(Drawable errorDrawable) {
        // use error drawable if desired
    }

    @Override
    public void onPrepareLoad(Drawable placeHolderDrawable) {
        // use placeholder drawable if desired
    }

}

Which lets you do this:

Picasso.with(yourContext)
          .load(yourImageUri)
          .into(yourListView);

Oblique

This deserves a check and a +1. Thank you. – Generosity

If I call resize between load and into then onBitmapLoaded is never called. Is there a way around this problem? I would like to be able to resize. – Generosity

@Generosity That's odd. onBitmapLoaded is called for me in both examples when I call resize. I looked into the problem and found this SO question which seems relevant. Hope this helps – Oblique