Try configuring an OkHttp3 client with authenticator, depending on your scheme and situation:
OkHttpClient okHttpClient = new OkHttpClient.Builder()
.authenticator(new Authenticator()
{
@Override
public Request authenticate(Route route, Response response) throws IOException
{
String credential = Credentials.basic("user", "pass");
return response.request().newBuilder()
.header("Authorization", credential)
.build();
}
})
.build();
Then, use that client in forming your Picasso object, but with okhttp3 you will have to use a OkHttp3Downloader instead, like so:
Picasso picasso = new Picasso.Builder(context)
.downloader(new OkHttp3Downloader(okHttpClient))
.build();
You can get the OkHttp3Downloader from https://github.com/JakeWharton/picasso2-okhttp3-downloader