Java tutorial
/* * Copyright (C) 2017 Emmanuel Galindo (https://emmanuel-galindo.github.io) * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.popumovies; import android.database.Cursor; import android.net.Uri; import android.os.Bundle; import android.support.annotation.Nullable; import android.support.v4.app.Fragment; import android.support.v4.app.LoaderManager; import android.support.v4.content.CursorLoader; import android.support.v4.content.Loader; import android.support.v4.widget.SwipeRefreshLayout; import android.support.v7.widget.GridLayoutManager; import android.support.v7.widget.RecyclerView; import android.util.Log; import android.view.LayoutInflater; import android.view.Menu; import android.view.MenuInflater; import android.view.MenuItem; import android.view.View; import android.view.ViewGroup; import android.widget.ListView; import com.popumovies.adapter.MovieAdapter; import com.popumovies.data.MovieContract.MovieEntry; import com.popumovies.sync.MovieSyncAdapter; import com.popumovies.utils.PrefUtil; /** * A placeholder fragment containing a simple view. */ public class MainActivityFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor> { private static final String LOG_TAG = MainActivityFragment.class.getSimpleName(); private static final String BUNDLE_RECYCLER_LAYOUT = "classname.recycler.layout"; private static final int MOVIE_LOADER = 0; private MovieAdapter mMovieAdapter; private RecyclerView mRecyclerView; private Menu mMenu; private int mPosition = ListView.INVALID_POSITION; private SwipeRefreshLayout mSwipeRefreshLayout; /** * A callback interface that all activities containing this fragment must * implement. This mechanism allows activities to be notified of item * selections. */ public interface Callback { /** * DetailFragmentCallback for when an item has been selected. */ void onItemSelected(int pos, long movieId); } public MainActivityFragment() { } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Log.d(LOG_TAG, "onCreate"); // Add this line in order for this fragment to handle menu events. setHasOptionsMenu(true); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { Log.d(LOG_TAG, "onCreateView"); View rootView = inflater.inflate(R.layout.fragment_main, container, false); mRecyclerView = (RecyclerView) rootView.findViewById(R.id.recycler_view); mSwipeRefreshLayout = (SwipeRefreshLayout) rootView.findViewById(R.id.swiperefresh); // use this setting to improve performance if you know that changes // in content do not change the layout size of the RecyclerView mRecyclerView.setHasFixedSize(true); mMovieAdapter = new MovieAdapter(getActivity(), null); mRecyclerView.setAdapter(mMovieAdapter); return rootView; } @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); // Prepare the loader. Either re-connect with an existing one, // or start a new one. getLoaderManager().initLoader(MOVIE_LOADER, null, this); } @Override public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) { inflater.inflate(R.menu.menu_main, menu); int item = PrefUtil.getInt(getActivity(), getString(R.string.pref_filter_label), R.id.action_sort_popularity); MenuItem menuItem = menu.findItem(item); if (menuItem == null) menuItem = menu.findItem(R.id.action_sort_popularity); menuItem.setChecked(true); mMenu = menu; } @Override public boolean onOptionsItemSelected(MenuItem item) { // Handle action bar item clicks here. The action bar will // automatically handle clicks on the Home/Up button, so long // as you specify a parent activity in AndroidManifest.xml. int id = item.getItemId(); if (id == R.id.action_refresh) { if (!mSwipeRefreshLayout.isRefreshing()) { mSwipeRefreshLayout.setRefreshing(true); updateMovie(); } return true; } else if ((id == R.id.action_sort_popularity) || (id == R.id.action_sort_votes) || (id == R.id.action_favorites)) { PrefUtil.setInt(getActivity(), getString(R.string.pref_filter_label), id); mMenu.findItem(R.id.action_sort_popularity).setChecked(false); mMenu.findItem(R.id.action_sort_votes).setChecked(false); mMenu.findItem(R.id.action_favorites).setChecked(false); mMenu.findItem(id).setChecked(true); restartLoader(); } else if (id == android.R.id.home) { getActivity().onBackPressed(); } return super.onOptionsItemSelected(item); } private void updateMovie() { Log.d(LOG_TAG, "in updateMovie"); MovieSyncAdapter.syncImmediately(getActivity()); } @Override public void onViewStateRestored(@Nullable Bundle savedInstanceState) { super.onViewStateRestored(savedInstanceState); if (savedInstanceState != null) { if (savedInstanceState.containsKey("scrollpos")) { int scrollToPos = savedInstanceState.getInt("scrollpos"); setPosition(scrollToPos); } } } @Override public void onSaveInstanceState(Bundle outState) { // - Make use of the LayoutManager capabilities to help saving the scroll position // When rotating, it will be only useful when returning to the orientation in where it was set. if (mRecyclerView != null) { outState.putParcelable(BUNDLE_RECYCLER_LAYOUT, mRecyclerView.getLayoutManager().onSaveInstanceState()); int scrollpos = ((GridLayoutManager) mRecyclerView.getLayoutManager()) .findFirstCompletelyVisibleItemPosition(); outState.putInt("scrollpos", scrollpos); } super.onSaveInstanceState(outState); } @Override public Loader<Cursor> onCreateLoader(int i, Bundle bundle) { Uri movieUri; int idFilter = PrefUtil.getInt(getActivity(), getString(R.string.pref_filter_label)); if (idFilter == R.id.action_sort_popularity) movieUri = MovieEntry.buildPopularMovieUri(); else if (idFilter == R.id.action_favorites) movieUri = MovieEntry.buildFavoriteMovieUri(); else if (idFilter == R.id.action_sort_votes) movieUri = MovieEntry.buildHighRatedMovieUri(); else movieUri = MovieEntry.buildPopularMovieUri(); return new CursorLoader(getActivity(), movieUri, null, null, null, null); } public void onLoadFinished(Loader<Cursor> loader, Cursor data) { Log.d(LOG_TAG, "onLoadFinished()"); int idFilter = PrefUtil.getInt(getActivity(), getString(R.string.pref_filter_label)); // if there's no data (as in initial load), refresh if (data.getCount() > 0 || idFilter == R.id.action_favorites) { mSwipeRefreshLayout.setRefreshing(false); mMovieAdapter.swapCursor(data); if (mPosition != ListView.INVALID_POSITION) { Log.d(LOG_TAG, "onLoadFinished - scrollToPosition " + mPosition); mRecyclerView.scrollToPosition(mPosition); } } else { updateMovie(); } } public void onLoaderReset(Loader<Cursor> loader) { // This is called when the last Cursor provided to onLoadFinished() // above is about to be closed. We need to make sure we are no // longer using it. mMovieAdapter.swapCursor(null); } public void restartLoader() { getLoaderManager().restartLoader(MOVIE_LOADER, null, this); } public void setPositionInList(int pos) { if (mRecyclerView.getLayoutManager() != null) mRecyclerView.getLayoutManager().scrollToPosition(pos); } public void setPosition(int position) { mPosition = position; } }