com.lkunic.libs.apptoolbox.twopane.fragments.ItemListFragment.java Source code

Introduction

Here is the source code for com.lkunic.libs.apptoolbox.twopane.fragments.ItemListFragment.java

Source

/**
 * Copyright (c) Luka Kunic 2015 / "ItemListFragment.java"
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software to deal in the software without restriction, including without
 * limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, provided that the licence notice is included
 * in all copies or substantial portions of the software.
 *
 * Created by lkunic on 08/04/2015.
 */
package com.lkunic.libs.apptoolbox.twopane.fragments;

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.ListView;

import com.lkunic.libs.apptoolbox.R;

/**
 * Base class for implementing a list fragment for the TwoPane master-detail flow.
 * Activities containing this fragment must implement the {@link ItemListFragment.OnItemSelectedListener}
 */
public abstract class ItemListFragment extends Fragment {
    /**
     * A dummy implementation of the {@link OnItemSelectedListener} interface that does
     * nothing. Used only when this fragment is not attached to an activity.
     */
    private static OnItemSelectedListener sDummyListener = new OnItemSelectedListener() {
        @Override
        public void onItemSelected(long id) {
            Log.e("ItemListFragment", "Dummy callback method called. Something is wrong with the implementation");
        }
    };

    // The fragment's current callback object, which is notified of list item clicks
    private OnItemSelectedListener mListener = sDummyListener;

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        // Activities containing this fragment must implement its callback
        if (!(activity instanceof OnItemSelectedListener)) {
            throw new IllegalStateException(
                    String.format("%s must implement fragment's callbacks.", activity.getClass().getName()));
        }

        mListener = (OnItemSelectedListener) activity;
    }

    // region Abstract methods

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_item_list, container, false);

        // Setup the item list
        ListView list = (ListView) view.findViewById(R.id.item_list);
        list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
                mListener.onItemSelected(id);
            }
        });

        // Call to the abstract method that is used by a derived class to add content to the list
        setupListContent(list);

        return view;
    }

    // endregion

    // region Listener implementation

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

        // Reset the active callback interface to the dummy implementation
        mListener = sDummyListener;
    }

    /**
     * Implement to set up list adapter and content. You can extend the ItemListCursorAdapter and use
     * it for populating your list using a cursor.
     */
    protected abstract void setupListContent(View list);

    /**
     * Returns the callback object.
     */
    protected OnItemSelectedListener getCallbacks() {
        return mListener;
    }

    /**
     * A callback interface that all activities containing this fragment must implement. This mechanism allows
     * activities to be notified of item selections.
     */
    public interface OnItemSelectedListener {
        /**
         * Callback for when an item has been selected.
         */
        void onItemSelected(long id);
    }

    // endregion
}