Android Picasso Try offline disk cache first, then go online and fetch the image


Example

first add the OkHttp to the gradle build file of the app module

compile 'com.squareup.picasso:picasso:2.5.2'
compile 'com.squareup.okhttp:okhttp:2.4.0'
compile 'com.jakewharton.picasso:picasso2-okhttp3-downloader:1.0.2'

Then make a class extending Application

import android.app.Application;

import com.squareup.picasso.OkHttpDownloader;
import com.squareup.picasso.Picasso;

public class Global extends Application {
    @Override
    public void onCreate() {
        super.onCreate();

        Picasso.Builder builder = new Picasso.Builder(this);
        builder.downloader(new OkHttpDownloader(this,Integer.MAX_VALUE));
        Picasso built = builder.build();
        built.setIndicatorsEnabled(true);
        built.setLoggingEnabled(true);
        Picasso.setSingletonInstance(built);

    }
}

add it to the Manifest file as follows :

<application
        android:name=".Global"
        .. >

</application>

Normal Usage

Picasso.with(getActivity())
.load(imageUrl)
.networkPolicy(NetworkPolicy.OFFLINE)
.into(imageView, new Callback() {
    @Override
    public void onSuccess() {
        //Offline Cache hit
    }

    @Override
    public void onError() {
        //Try again online if cache failed
        Picasso.with(getActivity())
                .load(imageUrl)
                .error(R.drawable.header)
                .into(imageView, new Callback() {
            @Override
            public void onSuccess() {
                 //Online download
            }

            @Override
            public void onError() {
                Log.v("Picasso","Could not fetch image");
            }
        });
    }
});

Link to original answer