Java tutorial
/* * Firetweet - Twitter client for Android * * Copyright (C) 2012-2015 Mariotaku Lee <mariotaku.lee@gmail.com> * * 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 org.getlantern.firetweet.loader.support; import android.content.Context; import android.content.SharedPreferences; import android.database.sqlite.SQLiteDatabase; import android.os.Handler; import android.util.Pair; import org.getlantern.jsonserializer.JSONFileIO; import org.getlantern.firetweet.app.FiretweetApplication; import org.getlantern.firetweet.model.ParcelableActivity; import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.concurrent.CopyOnWriteArrayList; import twitter4j.Activity; import twitter4j.Paging; import twitter4j.Twitter; import twitter4j.TwitterException; import static org.getlantern.firetweet.util.Utils.getTwitterInstance; import static org.getlantern.firetweet.util.Utils.truncateActivities; public abstract class Twitter4JActivitiesLoader extends ParcelableActivitiesLoader { private final Context mContext; private final long mAccountIds; private final long mMaxId, mSinceId; private final SQLiteDatabase mDatabase; private final Handler mHandler; private final Object[] mSavedStatusesFileArgs; private Comparator<ParcelableActivity> mComparator; public Twitter4JActivitiesLoader(final Context context, final long accountId, final long sinceId, final long maxId, final List<ParcelableActivity> data, final String[] savedStatusesArgs, final int tabPosition) { super(context, data, tabPosition); mContext = context; mAccountIds = accountId; mSinceId = sinceId; mMaxId = maxId; mDatabase = FiretweetApplication.getInstance(context).getSQLiteDatabase(); mHandler = new Handler(); mSavedStatusesFileArgs = savedStatusesArgs; } @SuppressWarnings("unchecked") @Override public final List<ParcelableActivity> loadInBackground() { final File serializationFile = getSerializationFile(); final List<ParcelableActivity> data = getData(); if (isFirstLoad() && getTabPosition() >= 0 && serializationFile != null) { final List<ParcelableActivity> cached = getCachedData(serializationFile); if (cached != null) { data.addAll(cached); if (mComparator != null) { Collections.sort(data, mComparator); } else { Collections.sort(data); } return new CopyOnWriteArrayList<>(data); } } final List<Activity> activities; final boolean truncated; final Context context = getContext(); final SharedPreferences prefs = context.getSharedPreferences(SHARED_PREFERENCES_NAME, Context.MODE_PRIVATE); final int loadItemLimit = prefs.getInt(KEY_LOAD_ITEM_LIMIT, DEFAULT_LOAD_ITEM_LIMIT); try { final Paging paging = new Paging(); paging.setCount(loadItemLimit); if (mMaxId > 0) { paging.setMaxId(mMaxId); } if (mSinceId > 0) { paging.setSinceId(mSinceId); } activities = new ArrayList<>(); truncated = truncateActivities(getActivities(getTwitter(), paging), activities, mSinceId); } catch (final TwitterException e) { // mHandler.post(new ShowErrorRunnable(e)); e.printStackTrace(); return new CopyOnWriteArrayList<>(data); } final Pair<Long, Long> minId; if (activities.isEmpty()) { minId = new Pair<>(-1L, -1L); } else { final Activity minActivity = Collections.min(activities); minId = new Pair<>(minActivity.getMinPosition(), minActivity.getMaxPosition()); } final boolean insertGap = minId.first > 0 && minId.second > 0 && activities.size() > 1 && !data.isEmpty() && !truncated; // mHandler.post(CacheUsersStatusesTask.getRunnable(context, new StatusListResponse(mAccountIds, activities))); for (final Activity activity : activities) { final long min = activity.getMinPosition(), max = activity.getMaxPosition(); final boolean deleted = deleteStatus(data, max); final boolean isGap = minId.first == min && minId.second == max && insertGap && !deleted; data.add(new ParcelableActivity(activity, mAccountIds, isGap)); } // final ParcelableActivity[] array = data.toArray(new ParcelableActivity[data.size()]); // for (int i = 0, size = array.length; i < size; i++) { // final ParcelableActivity status = array[i]; // if (shouldFilterActivity(mDatabase, status) && !status.is_gap && i != size - 1) { // deleteStatus(data, status.max_position); // } // } if (mComparator != null) { Collections.sort(data, mComparator); } else { Collections.sort(data); } saveCachedData(serializationFile, data); return new CopyOnWriteArrayList<>(data); } public final void setComparator(Comparator<ParcelableActivity> comparator) { mComparator = comparator; } protected abstract List<Activity> getActivities(Twitter twitter, Paging paging) throws TwitterException; protected final Twitter getTwitter() { return getTwitterInstance(mContext, mAccountIds, true, true); } protected abstract boolean shouldFilterActivity(final SQLiteDatabase database, final ParcelableActivity activity); private List<ParcelableActivity> getCachedData(final File file) { if (file == null) return null; try { return JSONFileIO.readArrayList(file); } catch (final IOException e) { e.printStackTrace(); } return null; } private File getSerializationFile() { if (mSavedStatusesFileArgs == null) return null; try { return JSONFileIO.getSerializationFile(mContext, mSavedStatusesFileArgs); } catch (final IOException e) { e.printStackTrace(); } return null; } private void saveCachedData(final File file, final List<ParcelableActivity> data) { if (file == null || data == null) return; final SharedPreferences prefs = mContext.getSharedPreferences(SHARED_PREFERENCES_NAME, Context.MODE_PRIVATE); final int databaseItemLimit = prefs.getInt(KEY_DATABASE_ITEM_LIMIT, DEFAULT_DATABASE_ITEM_LIMIT); try { final List<ParcelableActivity> activities = data.subList(0, Math.min(databaseItemLimit, data.size())); JSONFileIO.writeArray(file, activities.toArray(new ParcelableActivity[activities.size()])); } catch (final IOException e) { e.printStackTrace(); } } }