CourseListFragment.java

package neongarage.slakr.Course;

/**
 * Created by Aaron on 1/22/2015.
 * Refactored to RecyclerView 10/5/2015
 */
import android.support.v4.app.Fragment;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import neongarage.slakr.MySQLiteHelper;
import neongarage.slakr.R;

public class CourseListFragment extends Fragment {
    private RecyclerView mRecyclerView;
    private MySQLiteHelper db;
    private CourseAdapter courseAdapter;
    private RecyclerView.LayoutManager mLayoutManager;
    List<Course> courses = new ArrayList<Course>();
    private View view;

    private static final String TAG = "RecyclerViewFragment";
    private static final String KEY_LAYOUT_MANAGER = "layoutManager";
    private static final int SPAN_COUNT = 2;

    private enum LayoutManagerType {
        GRID_LAYOUT_MANAGER,
        LINEAR_LAYOUT_MANAGER
    }

    protected LayoutManagerType mCurrentLayoutManagerType;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        // Inflate the layout for this fragment
        view = inflater.inflate(R.layout.fragment_course_list, container, false);
        db = new MySQLiteHelper(getActivity());
        courses = db.getAllCourses();

        mRecyclerView =  (RecyclerView) view.findViewById(R.id.my_recycler_view);
        mLayoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
        mCurrentLayoutManagerType = LayoutManagerType.LINEAR_LAYOUT_MANAGER;

        if (savedInstanceState != null) {
            // Restore saved layout manager type.
            mCurrentLayoutManagerType = (LayoutManagerType) savedInstanceState
                    .getSerializable(KEY_LAYOUT_MANAGER);
        }
        setRecyclerViewLayoutManager(mCurrentLayoutManagerType);

        courseAdapter = new CourseAdapter(courses);
        mRecyclerView.setAdapter(courseAdapter);

        return view;
    }

    public void onSaveInstanceState(Bundle savedState) {

        super.onSaveInstanceState(savedState);
    }

    private HashMap<String, String> createCourse(String key, String name) {

        HashMap<String, String> planet = new HashMap<String, String>();
        planet.put(key, name);
        return planet;
    }

    public void addCourse(Course newCourse){
        courses.add(newCourse);
        db.addCourse(newCourse);
        courseAdapter.notifyItemInserted(courses.size()-1);

    }

    public void setRecyclerViewLayoutManager(LayoutManagerType layoutManagerType) {
        int scrollPosition = 0;

        // If a layout manager has already been set, get current scroll position.
        if (mRecyclerView.getLayoutManager() != null) {
            scrollPosition = ((LinearLayoutManager) mRecyclerView.getLayoutManager())
                    .findFirstCompletelyVisibleItemPosition();
        }

        switch (layoutManagerType) {
            case GRID_LAYOUT_MANAGER:
                mLayoutManager = new GridLayoutManager(getActivity(), SPAN_COUNT);
                mCurrentLayoutManagerType = LayoutManagerType.GRID_LAYOUT_MANAGER;
                break;
            case LINEAR_LAYOUT_MANAGER:
            default:
                mLayoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
                mCurrentLayoutManagerType = LayoutManagerType.LINEAR_LAYOUT_MANAGER;
                break;
        }

        mRecyclerView.setLayoutManager(mLayoutManager);
        mRecyclerView.scrollToPosition(scrollPosition);
        mRecyclerView.getItemAnimator();
    }

}