ChallengesContract is an agreement or contract between the View and Presenter

ChallengesContract.java

import android.database.Cursor;

/**
* The contract between the View and the Presenter
*/
public class ChallengesContract {

    public interface View {

        void showProgressBar();

        void dismissProgressBar();

        void showLayoutOnError(String message);

        void showLayoutOnSuccess();

        void showLayoutOnProgress();

        void showChallenges(Cursor cursor);

        void showLayoutOnEmpty();

    }

    public interface Presenter {

        void start();

        void clearOldChallenges();

        void getChallenges();
    }

}