Java tutorial
package edu.mit.mobile.android.locast.ver2.itineraries; /* * Copyright (C) 2011 MIT Mobile Experience Lab * * 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 2 * 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, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ import android.accounts.Account; import android.content.ContentResolver; import android.content.ContentUris; import android.content.Intent; import android.content.SharedPreferences; import android.content.SyncStatusObserver; import android.database.Cursor; import android.net.Uri; import android.os.Bundle; import android.os.Handler; import android.os.Message; import android.preference.PreferenceManager; import android.support.v4.app.FragmentActivity; import android.support.v4.app.LoaderManager; import android.support.v4.content.CursorLoader; import android.support.v4.content.Loader; import android.support.v4.widget.CursorAdapter; import android.util.Log; import android.view.ContextMenu; import android.view.ContextMenu.ContextMenuInfo; import android.view.LayoutInflater; import android.view.View; import android.view.View.OnClickListener; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.ListView; import android.widget.TextView; import com.stackoverflow.ArrayUtils; import edu.mit.mobile.android.appupdater.AppUpdateChecker; import edu.mit.mobile.android.imagecache.ImageCache; import edu.mit.mobile.android.imagecache.ImageLoaderAdapter; import edu.mit.mobile.android.imagecache.SimpleThumbnailCursorAdapter; import edu.mit.mobile.android.locast.Constants; import edu.mit.mobile.android.locast.accounts.Authenticator; import edu.mit.mobile.android.locast.accounts.AuthenticatorActivity; import edu.mit.mobile.android.locast.data.Itinerary; import edu.mit.mobile.android.locast.data.MediaProvider; import edu.mit.mobile.android.locast.net.NetworkClient; import edu.mit.mobile.android.locast.sync.LocastSyncService; import edu.mit.mobile.android.locast.ver2.R; import edu.mit.mobile.android.locast.ver2.browser.BrowserHome; import edu.mit.mobile.android.widget.RefreshButton; public class ItineraryList extends FragmentActivity implements LoaderManager.LoaderCallbacks<Cursor>, OnItemClickListener, OnClickListener { @SuppressWarnings("unused") private static final String TAG = ItineraryList.class.getSimpleName(); private CursorAdapter mAdapter; private ListView mListView; private Uri mUri; private ImageCache mImageCache; private boolean firstTime; private static final boolean REQUIRE_LOGIN = false; private final String[] ITINERARY_DISPLAY = new String[] { Itinerary._TITLE, Itinerary._THUMBNAIL, Itinerary._DESCRIPTION }; private final String[] ITINERARY_PROJECTION = ArrayUtils.concat(new String[] { Itinerary._ID }, ITINERARY_DISPLAY); private AppUpdateChecker mAppUpdateChecker; private static String LOADER_DATA = "edu.mit.mobile.android.locast.LOADER_DATA"; private boolean mSyncWhenLoaded = true; private static final int MSG_SET_REFRESHING = 100, MSG_SET_NOT_REFRESHING = 101; private RefreshButton mRefresh; private Object mSyncHandle; private final Handler mHandler = new Handler() { @Override public void handleMessage(Message msg) { switch (msg.what) { case MSG_SET_REFRESHING: Log.d(TAG, "refreshing..."); ((TextView) findViewById(android.R.id.empty)).setText(R.string.loading_data); mRefresh.setRefreshing(true); break; case MSG_SET_NOT_REFRESHING: Log.d(TAG, "done loading."); ((TextView) findViewById(android.R.id.empty)).setText(R.string.error_no_items_in_this_list); mRefresh.setRefreshing(false); break; } }; }; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.simple_list_activity); findViewById(R.id.refresh).setOnClickListener(this); findViewById(R.id.home).setOnClickListener(this); mListView = (ListView) findViewById(android.R.id.list); mListView.setOnItemClickListener(this); mListView.addFooterView(LayoutInflater.from(this).inflate(R.layout.list_footer, null), null, false); mListView.setEmptyView(findViewById(android.R.id.empty)); mRefresh = (RefreshButton) findViewById(R.id.refresh); mRefresh.setOnClickListener(this); if (Constants.USE_APPUPDATE_CHECKER) { mAppUpdateChecker = new AppUpdateChecker(this, getString(R.string.app_update_url), new AppUpdateChecker.OnUpdateDialog(this, getString(R.string.app_name))); mAppUpdateChecker.checkForUpdates(); } final Intent intent = getIntent(); final String action = intent.getAction(); mImageCache = ImageCache.getInstance(this); firstTime = checkFirstTime(); if (REQUIRE_LOGIN) { final NetworkClient nc = NetworkClient.getInstance(this); if (!nc.isAuthenticated()) { startActivityForResult(new Intent(this, AuthenticatorActivity.class), REQUEST_SIGNIN); return; } } if (Intent.ACTION_VIEW.equals(action)) { loadData(intent.getData()); } else if (Intent.ACTION_MAIN.equals(action)) { loadData(Itinerary.CONTENT_URI); } } @Override protected void onResume() { super.onResume(); mSyncWhenLoaded = true; mSyncHandle = ContentResolver.addStatusChangeListener(0xff, new SyncStatusObserver() { @Override public void onStatusChanged(int which) { Account a = Authenticator.getFirstAccount(ItineraryList.this); if (!ContentResolver.isSyncActive(a, MediaProvider.AUTHORITY) && !ContentResolver.isSyncPending(a, MediaProvider.AUTHORITY)) { Log.d(TAG, "Sync finished, should refresh naw!!"); mHandler.sendEmptyMessage(MSG_SET_NOT_REFRESHING); } else { Log.d(TAG, "Sync Active or Pending!!"); mHandler.sendEmptyMessage(MSG_SET_REFRESHING); } } }); //check if synch is in progress Account a = Authenticator.getFirstAccount(ItineraryList.this); if (!ContentResolver.isSyncActive(a, MediaProvider.AUTHORITY) && !ContentResolver.isSyncPending(a, MediaProvider.AUTHORITY)) { Log.d(TAG, "Sync finished, should refresh naw!!"); mHandler.sendEmptyMessage(MSG_SET_NOT_REFRESHING); } else { Log.d(TAG, "Sync Active or Pending!!"); mHandler.sendEmptyMessage(MSG_SET_REFRESHING); } } @Override protected void onPause() { super.onPause(); if (mSyncHandle != null) { ContentResolver.removeStatusChangeListener(mSyncHandle); } } @Override public void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) { super.onCreateContextMenu(menu, v, menuInfo); } private void loadData(Uri data) { final String type = getContentResolver().getType(data); if (!MediaProvider.TYPE_ITINERARY_DIR.equals(type)) { throw new IllegalArgumentException("cannot load type: " + type); } mAdapter = new SimpleThumbnailCursorAdapter(this, R.layout.itinerary_item, null, ITINERARY_DISPLAY, new int[] { android.R.id.text1, R.id.media_thumbnail, android.R.id.text2 }, new int[] { R.id.media_thumbnail }, 0); mListView.setAdapter(new ImageLoaderAdapter(this, mAdapter, mImageCache, new int[] { R.id.media_thumbnail }, 48, 48, ImageLoaderAdapter.UNIT_DIP)); final LoaderManager lm = getSupportLoaderManager(); final Bundle loaderArgs = new Bundle(); loaderArgs.putParcelable(LOADER_DATA, data); lm.initLoader(0, loaderArgs, this); setTitle(R.string.itineraries); mUri = data; } @Override public void setTitle(CharSequence title) { super.setTitle(title); ((TextView) findViewById(android.R.id.title)).setText(title); } @Override public void setTitle(int title) { super.setTitle(title); ((TextView) findViewById(android.R.id.title)).setText(title); } private void refresh(boolean explicitSync) { LocastSyncService.startSync(this, mUri, explicitSync); } @Override public Loader<Cursor> onCreateLoader(int id, Bundle args) { final Uri data = args.getParcelable(LOADER_DATA); final CursorLoader cl = new CursorLoader(this, data, ITINERARY_PROJECTION, null, null, Itinerary.SORT_DEFAULT); cl.setUpdateThrottle(Constants.UPDATE_THROTTLE); return cl; } @Override public void onLoadFinished(Loader<Cursor> loader, Cursor c) { mAdapter.swapCursor(c); if (mSyncWhenLoaded) { mSyncWhenLoaded = false; if (mListView.getAdapter().isEmpty()) { LocastSyncService.startExpeditedAutomaticSync(this, mUri); } else { refresh(false); } } } @Override public void onLoaderReset(Loader<Cursor> arg0) { mAdapter.swapCursor(null); } @Override public void onItemClick(AdapterView<?> adapter, View v, int position, long id) { startActivity(new Intent(Intent.ACTION_VIEW, ContentUris.withAppendedId(mUri, id))); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.refresh: refresh(true); break; case R.id.home: startActivity(new Intent(this, BrowserHome.class)); break; } } private final static int REQUEST_SIGNIN = 0; /** * @return true if this seems to be the first time running the app */ private boolean checkFirstTime() { final SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this); final boolean skip = prefs.getBoolean(Authenticator.PREF_SKIP_AUTH, false); return skip; } @Override protected void onActivityResult(int requestCode, int resultCode, Intent data) { switch (requestCode) { case REQUEST_SIGNIN: if (resultCode == RESULT_CANCELED) { finish(); } else if (resultCode == RESULT_OK) { refresh(false); } break; default: break; } } }