CODEWITHSUNDEEP
androidpicasso
patrick.elmquist
patrick.elmquist

Reputation: 2140

Picasso image url lookup before load

So I'm currently investigating the possibility to replace a lot of custom image loading AsyncTasks in a project, with the Picasso library and it seems promising. However there is one issue that I'm not completely sure how to solve using Picasso.

In this case we are downloading Album Art for music tracks, however when our ListView is to be shown we only have the track ids. So first we have to lookup an Album Art URL based on the track id and then load it into an ImageView. Currently we have an AsyncTask where we in doInBackground() first lookup the image URL and then load a Bitmap from it, which is then pasted to onPostExecute.

Is there any way to make this pre-lookup using Picasso or will we have to wrap the Picasso call in a AsyncTask that first perform the lookup (and feels like it kinda defeats the purpose).

Update: How it works now:

private class AlbumArtTask extends AsyncTask<String, Bitmap, Bitmap> {

    @Override
    protected Bitmap doInBackground(String... strings) {
        final String id = strings[0];

        // This part is what I'm asking for, basically to be able to make an Async
        // lookup of the url that will later be used by Picasso
        final Uri uri = getAlbumArtUriFromTrackId(id);

        // Creating the Bitmap and return it to be used in an ImageView
        // This part is handled by Picasso
        return bitmap = createBitmapFromUri(uri);
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        // load image into ImageView
    }
}

Update 2: Made up example of what I'm after

Picasso.with(mContext)
    .load(new UriProvider() {         

        // Get the actual image URI here
        public Uri getImageUri() {
            return getAlbumArtUriFromTrackId(id);
        }

     })

      // And load it here
     .into(mImageView);

Upvotes: 3

Views: 970

Answers (2)

Henrique Miranda
Henrique Miranda

Reputation: 994

I had to solve the same problem for my app. I used OkHTTP interceptor to redirect the request.

This is my picassa declaration:

OkHttpClient client = new OkHttpClient();
client.interceptors().add(new PhotoInterceptor());
Picasso picasso = new Picasso.Builder(context)
    .downloader(new OkHttpDownloader(client))
    .build();

This is a basic implementation of the interceptor:

public class PhotoInterceptor implements Interceptor {

    Gson gson = new Gson();

    @Override
    public Response intercept(Chain chain) throws IOException {
        Request request = chain.request();
        Response response = chain.proceed(request);
        if (response.isSuccessful()) {
            Photo photo = gson.fromJson(response.body().charStream(), Photo.class);
            if (photo!=null) {
                request = request.newBuilder()
                    .url(photo.getPhoto_file_url())
                    .build();
                response = chain.proceed(request);
            }
        }

        return response;
    }
}

Upvotes: 1

Kirankumar Zinzuvadia
Kirankumar Zinzuvadia

Reputation: 1249

You have to load images from your Album Art URL using Piccaso while your listView is created. Then on Detail screen of Track you have to call your actual image url to set it in imageview.

Edited

private class AlbumArtTask extends AsyncTask<String, Bitmap, Uri> {

        ImageView  mImageView;
        Context mContext;    
        public AlbumArtTask(Context context,ImageView imageView){
           this.mImageView=imageView;
           this.mContext=context;

        }

                @Override 
                protected Uri doInBackground(String... strings) {
                    final String id = strings[0];

                    // This part is what I'm asking for, basically to be able to make an Async 
                    // lookup of the url that will later be used by Picasso 
                    final Uri uri = getAlbumArtUriFromTrackId(id);

                    // Creating the Bitmap and return it to be used in an ImageView 
                    // This part is handled by Picasso 
                    return uri;
                } 

                @Override 
                protected void onPostExecute(Uri uri) {

                    // You have to pass imageview in constructor.
                    // load image into ImageView 
            Picasso.with(mContext).load(uri)/* And load it here*/.into(mImageView);
                } 
            }

Upvotes: 0

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