Java tutorial
/* * Popular Movies | The app allow users to discover the most popular movies playing * Copyright (C) <2016> <Alaa Elias> * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 3 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package com.example.android.popularmovies.app; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.content.SharedPreferences; import android.os.Bundle; import android.preference.PreferenceManager; import android.support.v4.app.Fragment; import android.support.v4.content.LocalBroadcastManager; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.AbsListView; import android.widget.AdapterView; import android.widget.GridView; import java.util.ArrayList; import java.util.HashMap; public class PopularMoviesFragment extends Fragment { // referance to grid view adapter public MoviesAdapter moviesAdapter; // declare broadcast tasks public static final int BROADCAST_TASK_CLEAN_LIST_AND_UPDATE = 900; public static final int BROADCAST_TASK_UPDATE_FRAGMENT_LAYOUT = 901; // reference to gridview private GridView gridView; // define log tag private final String LOG_TAG = PopularMovies.class.getSimpleName(); /** * The fragment argument representing the section number for this * fragment. */ private static final String ARG_SECTION_NUMBER = "section_number"; public PopularMoviesFragment() { } /** * Returns a new instance of this fragment for the given section * number. */ public static PopularMoviesFragment newInstance(int sectionNumber) { PopularMoviesFragment fragment = new PopularMoviesFragment(); Bundle args = new Bundle(); args.putInt(ARG_SECTION_NUMBER, sectionNumber); fragment.setArguments(args); return fragment; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.fragment_popular_movies, container, false); // get a reference to ListView gridView = (GridView) rootView.findViewById(R.id.movies_grid_view); // add on scroll listener to the grid view gridView.setOnScrollListener(new AbsListView.OnScrollListener() { public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { } public void onScrollStateChanged(AbsListView view, int scrollState) { if (scrollState == 0) { // before 2 last items witch are in the view port of the screen // we add page to the adapter counter to request data if (view.getCount() - view.getLastVisiblePosition() < 3) { // if the current page = the next page that means // its loading so we avoid send request again if (moviesAdapter.getNextPage() == moviesAdapter.getCurrentPage()) { moviesAdapter.setNextPage(); // get movies from api by page updateMovies(moviesAdapter.getNextPage()); } } } } }); gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { // when movie row clicked start the single movie details activity // and we pass the selected hashmap item to the details activity // via Intent Intent intent = new Intent(getActivity().getApplicationContext(), MovieDetails.class) .putExtra(MovieDetails.INTENT_HASHMAP, moviesAdapter.getItem(position)); startActivity(intent); } }); // create and attach adapter to gridview createGridViewAdapter(); return rootView; } // to fetch movies from api by page private void updateMovies(int page) { // check the movie view mode and change the grid columns numbers in one row if (moviesAdapter.MOVIES_VIEW.equalsIgnoreCase(getString(R.string.pref_movies_view_grid))) { gridView.setNumColumns(GridView.AUTO_FIT); } else if (moviesAdapter.MOVIES_VIEW.equalsIgnoreCase(getString(R.string.pref_movies_view_list))) { gridView.setNumColumns(1); } // run background task and fetch from api data FetchMoviesTask moviesTask = new FetchMoviesTask(getContext(), moviesAdapter); moviesTask.execute(String.valueOf(page)); } @Override public void onStart() { super.onStart(); updateMovies(1); } @Override public void onResume() { super.onResume(); // register the broadcast receiver IntentFilter fragmentTaskFilter = new IntentFilter("fragment.tasks"); LocalBroadcastManager.getInstance(getActivity()).registerReceiver(popularMoviesFragmentBCReceiver, fragmentTaskFilter); } @Override public void onDestroy() { super.onDestroy(); // register the broadcast receiver LocalBroadcastManager.getInstance(getActivity()).unregisterReceiver(popularMoviesFragmentBCReceiver); } private BroadcastReceiver popularMoviesFragmentBCReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { final int task = intent.getIntExtra("pupular.movies.fragment", -1); if (task == BROADCAST_TASK_CLEAN_LIST_AND_UPDATE) { // recreate and attach adapter to gridview createGridViewAdapter(); // reload the gridview with data from api updateMovies(1); } else if (task == BROADCAST_TASK_UPDATE_FRAGMENT_LAYOUT) { // recreate and attach adapter to gridview createGridViewAdapter(); // reload the gridview with data from api updateMovies(1); } } }; // get the saved value from sharedPreferences private void updateMoviesViewMode() { SharedPreferences sharedPreferences = PreferenceManager .getDefaultSharedPreferences(getActivity().getApplicationContext()); String moviesViewMode = sharedPreferences.getString(getString(R.string.pref_movies_view), getString(R.string.pref_movies_view_list)); // update the value inside the adapter moviesAdapter.MOVIES_VIEW = moviesViewMode; } private void createGridViewAdapter() { // MoviesAdapter will take the data from a the list and create the the ListView items moviesAdapter = new MoviesAdapter(new ArrayList<HashMap<String, String>>(), getActivity(), getContext(), gridView); updateMoviesViewMode(); // attach adapter to gridview gridView.setAdapter(moviesAdapter); } }