Java tutorial
/* * Twidere - Twitter client for Android * * Copyright (C) 2012-2014 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.mariotaku.twidere.loader; import static org.mariotaku.twidere.util.Utils.getTwitterInstance; import static org.mariotaku.twidere.util.Utils.truncateStatuses; import android.content.Context; import android.content.SharedPreferences; import android.database.sqlite.SQLiteDatabase; import android.os.Handler; import org.mariotaku.jsonserializer.JSONFileIO; import org.mariotaku.twidere.R; import org.mariotaku.twidere.app.TwidereApplication; import org.mariotaku.twidere.model.ParcelableStatus; import org.mariotaku.twidere.task.CacheUsersStatusesTask; import org.mariotaku.twidere.util.TwitterWrapper.StatusListResponse; import twitter4j.Paging; import twitter4j.Status; import twitter4j.Twitter; import twitter4j.TwitterException; import java.io.File; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.List; import java.util.concurrent.CopyOnWriteArrayList; public abstract class Twitter4JStatusesLoader extends ParcelableStatusesLoader { private final Context mContext; private final long mAccountId; private final long mMaxId, mSinceId; private final boolean mHiResProfileImage; private final SQLiteDatabase mDatabase; private final Handler mHandler; private final Object[] mSavedStatusesFileArgs; public Twitter4JStatusesLoader(final Context context, final long account_id, final long max_id, final long since_id, final List<ParcelableStatus> data, final String[] saved_statuses_args, final int tab_position) { super(context, data, tab_position); mContext = context; mAccountId = account_id; mMaxId = max_id; mSinceId = since_id; mHiResProfileImage = context.getResources().getBoolean(R.bool.hires_profile_image); mDatabase = TwidereApplication.getInstance(context).getSQLiteDatabase(); mHandler = new Handler(); mSavedStatusesFileArgs = saved_statuses_args; } @SuppressWarnings("unchecked") @Override public final List<ParcelableStatus> loadInBackground() { final File serializationFile = getSerializationFile(); final List<ParcelableStatus> data = getData(); if (isFirstLoad() && getTabPosition() >= 0 && serializationFile != null) { final List<ParcelableStatus> cached = getCachedData(serializationFile); if (cached != null) { data.addAll(cached); Collections.sort(data); return new CopyOnWriteArrayList<ParcelableStatus>(data); } } final List<Status> statuses; 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 - 1); } statuses = new ArrayList<Status>(); truncated = truncateStatuses(getStatuses(getTwitter(), paging), statuses, mSinceId); } catch (final TwitterException e) { // mHandler.post(new ShowErrorRunnable(e)); e.printStackTrace(); return new CopyOnWriteArrayList<ParcelableStatus>(data); } final long minStatusId = statuses.isEmpty() ? -1 : Collections.min(statuses).getId(); final boolean insertGap = minStatusId > 0 && statuses.size() > 1 && !data.isEmpty() && !truncated; mHandler.post(CacheUsersStatusesTask.getRunnable(context, new StatusListResponse(mAccountId, statuses))); for (final Status status : statuses) { final long id = status.getId(); final boolean deleted = deleteStatus(data, id); data.add(new ParcelableStatus(status, mAccountId, minStatusId == id && insertGap && !deleted, mHiResProfileImage)); } Collections.sort(data); final ParcelableStatus[] array = data.toArray(new ParcelableStatus[data.size()]); for (int i = 0, size = array.length; i < size; i++) { final ParcelableStatus status = array[i]; if (shouldFilterStatus(mDatabase, status) && !status.is_gap && i != size - 1) { deleteStatus(data, status.id); } } saveCachedData(serializationFile, data); return new CopyOnWriteArrayList<ParcelableStatus>(data); } protected abstract List<Status> getStatuses(Twitter twitter, Paging paging) throws TwitterException; protected final Twitter getTwitter() { return getTwitterInstance(mContext, mAccountId, true, true); } protected abstract boolean shouldFilterStatus(final SQLiteDatabase database, final ParcelableStatus status); private List<ParcelableStatus> 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<ParcelableStatus> 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<ParcelableStatus> activities = data.subList(0, Math.min(databaseItemLimit, data.size())); JSONFileIO.writeArray(file, activities.toArray(new ParcelableStatus[activities.size()])); } catch (final IOException e) { e.printStackTrace(); } } }