package com.castelijns.mmdemo.app;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.View;

import butterknife.ButterKnife;
import butterknife.Unbinder;

public class BaseFragment extends Fragment implements BaseView {

    private Unbinder unbinder;

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        unbinder = ButterKnife.bind(this, view);
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();

        if (unbinder != null) {
            unbinder.unbind();
            unbinder = null;
        }
    }

    @Override
    public Context getContext() {
        return getActivity();
    }
}

package com.castelijns.mmdemo.app;

import android.content.Context;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.View;

import butterknife.ButterKnife;
import butterknife.Unbinder;

public abstract class BaseFragment extends Fragment implements BaseView {

    private Unbinder unbinder;

    @Override
    public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        unbinder = ButterKnife.bind(this, view);
    }

    @Override
    public void onDestroyView() {
        super.onDestroyView();

        if (unbinder != null) {
            unbinder.unbind();
            unbinder = null;
        }
    }

    @Override
    public Context getContext() {
        return getActivity();
    }
}

Make BaseFragment abstract