Java tutorial
/* * Copyright 2011 Google Inc. * Copyright 2011 Peter Kuterna * * 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 net.peterkuterna.android.apps.devoxxsched.ui; import net.peterkuterna.android.apps.devoxxsched.R; import net.peterkuterna.android.apps.devoxxsched.provider.CfpContract; import net.peterkuterna.android.apps.devoxxsched.provider.CfpContract.Sessions; import net.peterkuterna.android.apps.devoxxsched.provider.CfpContract.Tracks; import net.peterkuterna.android.apps.devoxxsched.util.ActivityHelper; import net.peterkuterna.android.apps.devoxxsched.util.AnalyticsUtils; import net.peterkuterna.android.apps.devoxxsched.util.UIUtils; import android.content.Context; import android.content.Intent; import android.database.ContentObserver; import android.database.Cursor; import android.net.Uri; import android.os.Bundle; import android.os.Handler; import android.os.SystemClock; import android.provider.BaseColumns; import android.support.v4.app.ListFragment; import android.support.v4.app.LoaderManager; import android.support.v4.app.LoaderManager.LoaderCallbacks; import android.support.v4.content.CursorLoader; import android.support.v4.content.Loader; import android.support.v4.widget.CursorAdapter; import android.text.Spannable; import android.text.TextUtils; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ListView; import android.widget.TextView; public class SessionsFragment extends ListFragment { private static final String STATE_CHECKED_POSITION = "checkedPosition"; public static final String EXTRA_TRACK = "net.peterkuterna.android.apps.devoxxsched.extra.TRACK"; public static final String EXTRA_TRACK_COLOR = "net.peterkuterna.android.apps.devoxxsched.extra.TRACK_COLOR"; private CursorAdapter mAdapter; private int mCheckedPosition = -1; private Uri mSessionsUri; private long mNewSessionTimestamp = -1; private String mTrackName = null; private int mTrackColor = -1; private Handler mHandler = new Handler(); private Handler mMessageQueueHandler = new Handler(); @Override public void onActivityCreated(Bundle savedInstanceState) { super.onActivityCreated(savedInstanceState); setEmptyText(getString(R.string.empty_sessions)); getListView().setChoiceMode(ListView.CHOICE_MODE_SINGLE); reloadFromArguments(getArguments(), false); setListShown(false); if (savedInstanceState != null) { mCheckedPosition = savedInstanceState.getInt(STATE_CHECKED_POSITION, -1); } } public void reloadFromArguments(Bundle arguments, boolean reset) { mCheckedPosition = -1; // Load new arguments final Intent intent = ActivityHelper.fragmentArgumentsToIntent(arguments); mSessionsUri = intent.getData(); if (mSessionsUri == null) { return; } mNewSessionTimestamp = intent.getLongExtra(NewSessionsActivity.EXTRA_NEW_SESSION_TIMESTAMP, -1); final int sessionsQueryId; if (!CfpContract.Sessions.isSearchUri(mSessionsUri)) { mAdapter = new SessionsAdapter(getActivity(), null); sessionsQueryId = SessionsQuery._TOKEN; } else { mAdapter = new SearchAdapter(getActivity(), null); sessionsQueryId = SearchQuery._TOKEN; } setListAdapter(mAdapter); if (!reset) { getLoaderManager().initLoader(sessionsQueryId, null, mSessionsLoaderCallback); } else { getLoaderManager().restartLoader(sessionsQueryId, null, mSessionsLoaderCallback); } mTrackName = intent.getStringExtra(Intent.EXTRA_TITLE); mTrackColor = intent.getIntExtra(EXTRA_TRACK_COLOR, -1); final Uri trackUri = intent.getParcelableExtra(SessionsFragment.EXTRA_TRACK); if (!TextUtils.isEmpty(mTrackName)) { AnalyticsUtils.getInstance(getActivity()).trackPageView("/Sessions/" + mTrackName); updateTrackData(); } if (TextUtils.isEmpty(mTrackName) && mTrackColor == -1 && trackUri != null) { Bundle args = new Bundle(); args.putParcelable("uri", trackUri); getLoaderManager().initLoader(TracksQuery._TOKEN, args, mTrackLoaderCallback); } } @Override public void onResume() { super.onResume(); mMessageQueueHandler.post(mRefreshSessionsRunnable); getActivity().getContentResolver().registerContentObserver(CfpContract.Sessions.CONTENT_URI, true, mSessionChangesObserver); if (mSessionsUri != null) { if (!CfpContract.Sessions.isSearchUri(mSessionsUri)) { getLoaderManager().restartLoader(SessionsQuery._TOKEN, null, mSessionsLoaderCallback); } else { getLoaderManager().restartLoader(SearchQuery._TOKEN, null, mSessionsLoaderCallback); } } } @Override public void onPause() { super.onPause(); mMessageQueueHandler.removeCallbacks(mRefreshSessionsRunnable); getActivity().getContentResolver().unregisterContentObserver(mSessionChangesObserver); } @Override public void onSaveInstanceState(Bundle outState) { super.onSaveInstanceState(outState); outState.putInt(STATE_CHECKED_POSITION, mCheckedPosition); } /** {@inheritDoc} */ @Override public void onListItemClick(ListView l, View v, int position, long id) { // Launch viewer for specific session, passing along any track knowledge // that should influence the title-bar. final Cursor cursor = (Cursor) mAdapter.getItem(position); final String sessionId = cursor.getString(SessionsQuery.SESSION_ID); final String title = cursor.getString(SessionsQuery.SESSION_TITLE); AnalyticsUtils.getInstance(getActivity()).trackEvent("Sessions", "Click", title, 0); getListView().setItemChecked(position, true); mCheckedPosition = position; final Uri sessionUri = CfpContract.Sessions.buildSessionUri(sessionId); final Intent intent = new Intent(Intent.ACTION_VIEW, sessionUri); intent.putExtra(Intent.EXTRA_TITLE, mTrackName); intent.putExtra(SessionDetailFragment.EXTRA_TRACK_COLOR, mTrackColor); ((BaseActivity) getSupportActivity()).openActivityOrFragment(intent); } public void clearCheckedPosition() { if (mCheckedPosition >= 0) { if (getView() != null) { getListView().setItemChecked(mCheckedPosition, false); } mCheckedPosition = -1; } } private void updateTrackData() { if (!UIUtils.isHoneycombTablet(getActivity())) { UIUtils.setActionBarData(getSupportActivity(), mTrackName, mTrackColor); } } private LoaderManager.LoaderCallbacks<Cursor> mSessionsLoaderCallback = new LoaderCallbacks<Cursor>() { @Override public Loader<Cursor> onCreateLoader(int id, Bundle args) { if (id == SessionsQuery._TOKEN) { final String selection = mNewSessionTimestamp != -1 ? (Sessions.SESSION_NEW_TIMESTAMP + "=?") : null; final String[] selectionArgs = mNewSessionTimestamp != -1 ? (new String[] { String.valueOf(mNewSessionTimestamp) }) : null; return new CursorLoader(getActivity(), mSessionsUri, SessionsQuery.PROJECTION, selection, selectionArgs, CfpContract.Sessions.DEFAULT_SORT); } else if (id == SearchQuery._TOKEN) { return new CursorLoader(getActivity(), mSessionsUri, SearchQuery.PROJECTION, null, null, CfpContract.Sessions.DEFAULT_SORT); } return null; } @Override public void onLoadFinished(Loader<Cursor> loader, Cursor data) { mAdapter.swapCursor(data); if (getView() != null) { if (isResumed()) { setListShown(true); } else { setListShownNoAnimation(true); } } if (mCheckedPosition >= 0 && getView() != null) { getListView().setItemChecked(mCheckedPosition, true); } } @Override public void onLoaderReset(Loader<Cursor> loader) { mAdapter.swapCursor(null); } }; private LoaderManager.LoaderCallbacks<Cursor> mTrackLoaderCallback = new LoaderCallbacks<Cursor>() { @Override public Loader<Cursor> onCreateLoader(int id, Bundle args) { final Uri uri = args.getParcelable("uri"); return new CursorLoader(getActivity(), uri, TracksQuery.PROJECTION, null, null, null); } @Override public void onLoadFinished(Loader<Cursor> loader, Cursor data) { if (!data.moveToFirst()) { return; } mTrackName = data.getString(TracksQuery.TRACK_NAME); mTrackColor = data.getInt(TracksQuery.TRACK_COLOR); mHandler.post(new Runnable() { @Override public void run() { updateTrackData(); } }); AnalyticsUtils.getInstance(getActivity()).trackPageView("/Sessions/" + mTrackName); } @Override public void onLoaderReset(Loader<Cursor> loader) { } }; private ContentObserver mSessionChangesObserver = new ContentObserver(new Handler()) { @Override public void onChange(boolean selfChange) { if (getActivity() != null) { if (mSessionsUri != null) { if (CfpContract.Sessions.isSearchUri(mSessionsUri)) { getLoaderManager().restartLoader(SearchQuery._TOKEN, null, mSessionsLoaderCallback); } else if (!CfpContract.Sessions.isNewSessionsUri(mSessionsUri)) { getLoaderManager().restartLoader(SessionsQuery._TOKEN, null, mSessionsLoaderCallback); } } } } }; private Runnable mRefreshSessionsRunnable = new Runnable() { public void run() { if (mAdapter != null) { // This is used to refresh session title colors. mAdapter.notifyDataSetChanged(); } // Check again on the next quarter hour, with some padding to // account for network // time differences. long nextQuarterHour = (SystemClock.uptimeMillis() / 900000 + 1) * 900000 + 5000; mMessageQueueHandler.postAtTime(mRefreshSessionsRunnable, nextQuarterHour); } }; /** * {@link CursorAdapter} that renders a {@link SessionsQuery}. */ private class SessionsAdapter extends CursorAdapter { public SessionsAdapter(Context context, Cursor cursor) { super(context, cursor, 0); } /** {@inheritDoc} */ @Override public View newView(Context context, Cursor cursor, ViewGroup parent) { return LayoutInflater.from(context).inflate(R.layout.list_item_session, parent, false); } /** {@inheritDoc} */ @Override public void bindView(View view, Context context, Cursor cursor) { final TextView titleView = (TextView) view.findViewById(R.id.session_title); final TextView subtitleView = (TextView) view.findViewById(R.id.session_subtitle); titleView.setText(cursor.getString(SessionsQuery.SESSION_TITLE)); // Format time block this session occupies final long blockStart = cursor.getLong(SessionsQuery.BLOCK_START); final long blockEnd = cursor.getLong(SessionsQuery.BLOCK_END); final String roomName = cursor.getString(SessionsQuery.ROOM_NAME); final String subtitle = UIUtils.formatSessionSubtitle(blockStart, blockEnd, roomName, context); subtitleView.setText(subtitle); final boolean starred = cursor.getInt(SessionsQuery.SESSION_STARRED) != 0; view.findViewById(R.id.star_button).setVisibility(starred ? View.VISIBLE : View.INVISIBLE); // Possibly indicate that the session has occurred in the past. UIUtils.setSessionTitleColor(blockStart, blockEnd, titleView, subtitleView); } } /** * {@link CursorAdapter} that renders a {@link SearchQuery}. */ private class SearchAdapter extends CursorAdapter { public SearchAdapter(Context context, Cursor cursor) { super(context, cursor, 0); } /** {@inheritDoc} */ @Override public View newView(Context context, Cursor cursor, ViewGroup parent) { return LayoutInflater.from(context).inflate(R.layout.list_item_session, parent, false); } /** {@inheritDoc} */ @Override public void bindView(View view, Context context, Cursor cursor) { ((TextView) view.findViewById(R.id.session_title)).setText(cursor.getString(SearchQuery.TITLE)); final String snippet = cursor.getString(SearchQuery.SEARCH_SNIPPET); final Spannable styledSnippet = UIUtils.buildStyledSnippet(snippet); ((TextView) view.findViewById(R.id.session_subtitle)).setText(styledSnippet); final boolean starred = cursor.getInt(SearchQuery.STARRED) != 0; view.findViewById(R.id.star_button).setVisibility(starred ? View.VISIBLE : View.INVISIBLE); } } /** * {@link Sessions} query parameters. */ private interface SessionsQuery { int _TOKEN = 0x1; String[] PROJECTION = { BaseColumns._ID, CfpContract.Sessions.SESSION_ID, CfpContract.Sessions.SESSION_TITLE, CfpContract.Sessions.SESSION_STARRED, CfpContract.Blocks.BLOCK_START, CfpContract.Blocks.BLOCK_END, CfpContract.Rooms.ROOM_NAME, }; int _ID = 0; int SESSION_ID = 1; int SESSION_TITLE = 2; int SESSION_STARRED = 3; int BLOCK_START = 4; int BLOCK_END = 5; int ROOM_NAME = 6; } /** * {@link Tracks} query parameters. */ private interface TracksQuery { int _TOKEN = 0x2; String[] PROJECTION = { CfpContract.Tracks.TRACK_NAME, CfpContract.Tracks.TRACK_COLOR, }; int TRACK_NAME = 0; int TRACK_COLOR = 1; } /** * {@link Sessions} search query parameters. */ private interface SearchQuery { int _TOKEN = 0x3; String[] PROJECTION = { BaseColumns._ID, CfpContract.Sessions.SESSION_ID, CfpContract.Sessions.SESSION_TITLE, CfpContract.Sessions.SEARCH_SNIPPET, CfpContract.Sessions.SESSION_STARRED, }; int _ID = 0; int SESSION_ID = 1; int TITLE = 2; int SEARCH_SNIPPET = 3; int STARRED = 4; } }