Java tutorial
/* * Copyright (C) 2011 - 2013 Niall 'Rivernile' Scott * * This software is provided 'as-is', without any express or implied * warranty. In no event will the authors or contributors be held liable for * any damages arising from the use of this software. * * The aforementioned copyright holder(s) hereby grant you a * non-transferrable right to use this software for any purpose (including * commercial applications), and to modify it and redistribute it, subject to * the following conditions: * * 1. This notice may not be removed or altered from any file it appears in. * * 2. Any modifications made to this software, except those defined in * clause 3 of this agreement, must be released under this license, and * the source code of any modifications must be made available on a * publically accessible (and locateable) website, or sent to the * original author of this software. * * 3. Software modifications that do not alter the functionality of the * software but are simply adaptations to a specific environment are * exempt from clause 2. */ package uk.org.rivernile.edinburghbustracker.android.fragments.general; import android.app.Activity; import android.content.Context; import android.database.Cursor; import android.os.Bundle; import android.support.v4.app.ListFragment; import android.support.v4.app.LoaderManager; import android.support.v4.content.Loader; import android.support.v4.widget.CursorAdapter; import android.text.Html; 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.Button; import android.widget.TextView; import uk.org.rivernile.android.utils.SimpleCursorLoader; import uk.org.rivernile.edinburghbustracker.android.BusStopDatabase; import uk.org.rivernile.edinburghbustracker.android.R; import uk.org.rivernile.edinburghbustracker.android.SettingsDatabase; import uk.org.rivernile.edinburghbustracker.android.fragments.dialogs.DeleteAllAlertsDialogFragment; import uk.org.rivernile.edinburghbustracker.android.fragments.dialogs.DeleteProximityAlertDialogFragment; import uk.org.rivernile.edinburghbustracker.android.fragments.dialogs.DeleteTimeAlertDialogFragment; /** * This Fragment allows the users to view what proximity and time alerts they * have set and allow them to delete single alerts or all alerts. * * Instances of this Fragment are retained between rotation changes. * * @author Niall Scott */ public class AlertManagerFragment extends ListFragment implements LoaderManager.LoaderCallbacks<Cursor>, DeleteAllAlertsDialogFragment.Callbacks, DeleteProximityAlertDialogFragment.Callbacks, DeleteTimeAlertDialogFragment.Callbacks { private Callbacks callbacks; private AlertCursorAdapter ad; /** * {@inheritDoc} */ @Override public void onAttach(final Activity activity) { super.onAttach(activity); try { callbacks = (Callbacks) activity; } catch (ClassCastException e) { throw new IllegalStateException( activity.getClass().getName() + " does not implement " + Callbacks.class.getName()); } } /** * {@inheritDoc} */ @Override public void onCreate(final Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Create the adapter. ad = new AlertCursorAdapter(getActivity(), null); setListAdapter(ad); // Tell the underlying Activity that this Fragment hosts an options // menu. setHasOptionsMenu(true); } /** * {@inheritDoc} */ @Override public View onCreateView(final LayoutInflater inflater, final ViewGroup container, final Bundle savedInstanceState) { return inflater.inflate(R.layout.alertmanager, container, false); } /** * {@inheritDoc} */ @Override public void onResume() { super.onResume(); // Reload the data every time onResume is called. getLoaderManager().restartLoader(0, null, this); } /** * {@inheritDoc} */ @Override public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) { // Inflate the menu. inflater.inflate(R.menu.alertmanager_option_menu, menu); } /** * {@inheritDoc} */ @Override public void onPrepareOptionsMenu(final Menu menu) { super.onPrepareOptionsMenu(menu); final MenuItem deleteAllItem = menu.findItem(R.id.alertmanager_option_menu_delete_all); // Only enable the 'Delete all alerts' item when there's alerts to // delete. if (ad.getCount() > 0) { deleteAllItem.setEnabled(true); } else { deleteAllItem.setEnabled(false); } } /** * {@inheritDoc} */ @Override public boolean onOptionsItemSelected(final MenuItem item) { switch (item.getItemId()) { case R.id.alertmanager_option_menu_delete_all: // Show the 'Delete all alerts' confirmation DialogFragment. callbacks.onShowConfirmDeleteAllAlerts(); return true; default: return super.onOptionsItemSelected(item); } } /** * {@inheritDoc} */ @Override public Loader<Cursor> onCreateLoader(final int id, final Bundle args) { // Return the only Loader for this Fragment. return new AlertCursorLoader(getActivity()); } /** * {@inheritDoc} */ @Override public void onLoadFinished(final Loader<Cursor> loader, final Cursor c) { if (isAdded()) { // Swap in the new Cursor. The superclass deals with closing the old // Cursor object. ad.swapCursor(c); // There may be change in status so refresh the options menu. getActivity().supportInvalidateOptionsMenu(); } else { if (c != null) { c.close(); } } } /** * {@inheritDoc} */ @Override public void onLoaderReset(final Loader<Cursor> loader) { // If the Loader has been reset, empty the ListAdapter. ad.swapCursor(null); } /** * {@inheritDoc} */ @Override public void onConfirmAllAlertsDeletion() { // All alerts have been removed, refresh the data. getLoaderManager().restartLoader(0, null, this); } /** * {@inheritDoc} */ @Override public void onCancelAllAlertsDeletion() { // Nothing to do here. } /** * {@inheritDoc} */ @Override public void onConfirmProximityAlertDeletion() { // The proximity alert has been removed, refresh the data. getLoaderManager().restartLoader(0, null, this); } /** * {@inheritDoc} */ @Override public void onCancelProximityAlertDeletion() { // Nothing to do here. } /** * {@inheritDoc} */ @Override public void onConfirmTimeAlertDeletion() { // The time alert has been removed, refresh the data. getLoaderManager().restartLoader(0, null, this); } /** * {@inheritDoc} */ @Override public void onCancelTimeAlertDeletion() { // Nothing to do here. } /** * This class allows the alert list to be loaded in the background. */ private static class AlertCursorLoader extends SimpleCursorLoader { private final SettingsDatabase sd; /** * Create a new AlertCursorLoader. * * @param context A Context object. */ public AlertCursorLoader(final Context context) { super(context); sd = SettingsDatabase.getInstance(context.getApplicationContext()); } /** * {@inheritDoc} */ @Override public Cursor loadInBackground() { final Cursor c = sd.getAllAlerts(); // This ensures the Cursor window is set properly. if (c != null) c.getCount(); return c; } } /** * This CursorAdapter shows a list of alerts that have been set by the user. */ private class AlertCursorAdapter extends CursorAdapter { private BusStopDatabase bsd; /** * Create a new AlertCursorAdapter. * * @param context A Context object. * @param c The Cursor to use. */ public AlertCursorAdapter(final Context context, final Cursor c) { super(context, c, 0); // Get a reference to the BusStopDatabase. bsd = BusStopDatabase.getInstance(context.getApplicationContext()); } /** * This getView() overrides the superclass implementation as we do not * want to use convertView here. There can only be 1 item of its type * shown in the list and therefore will never have a proper item to * convert from. This means that the View will need to be inflated from * XML each time it needs to be used. * * @param position The position in the list, and therefore the Cursor, * to be used. * @param convertView A View to be converted from. This is not used in * this implementation. * @param parent The parent View. */ @Override public View getView(final int position, final View convertView, final ViewGroup parent) { // Move the Cursor in to position. Throw an Exception if this is // not possible. if (!mCursor.moveToPosition(position)) { throw new IllegalStateException("Couldn't move cursor to " + "position " + position); } // Create a new View. final View v = newView(mContext, mCursor, parent); // Populate the View bindView(v, mContext, mCursor); return v; } /** * {@inheritDoc} */ @Override public View newView(final Context context, final Cursor c, final ViewGroup container) { final LayoutInflater inflater = LayoutInflater.from(context); // The inflated layout depends on what time of alert it is showing. switch (c.getInt(1)) { case SettingsDatabase.ALERTS_TYPE_PROXIMITY: return inflater.inflate(R.layout.alertmanager_list_proximity, container, false); case SettingsDatabase.ALERTS_TYPE_TIME: return inflater.inflate(R.layout.alertmanager_list_time, container, false); default: return null; } } /** * {@inheritDoc} */ @Override public void bindView(final View view, final Context context, final Cursor c) { // Get the stopCode and locality information. final String stopCode = c.getString(3); final String locality = bsd.getLocalityForStopCode(stopCode); final String busStop; // Append the locality if it is available. if (locality != null) { busStop = context.getString(R.string.busstop_locality_coloured, bsd.getNameForBusStop(stopCode), locality, stopCode); } else { busStop = context.getString(R.string.busstop_coloured, bsd.getNameForBusStop(stopCode), stopCode); } Button btn; TextView txt; // How the View is populated depends on the alert type. switch (c.getInt(1)) { case SettingsDatabase.ALERTS_TYPE_PROXIMITY: btn = (Button) view.findViewById(R.id.btnRemoveProxAlert); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(final View v) { callbacks.onShowConfirmDeleteProximityAlert(); } }); // Set information text. txt = (TextView) view.findViewById(R.id.txtAlertManProx); txt.setText( Html.fromHtml(context.getString(R.string.alertmanager_prox_text, c.getInt(4), busStop))); break; case SettingsDatabase.ALERTS_TYPE_TIME: btn = (Button) view.findViewById(R.id.btnRemoveTimeAlert); btn.setOnClickListener(new View.OnClickListener() { @Override public void onClick(final View v) { callbacks.onShowConfirmDeleteTimeAlert(); } }); txt = (TextView) view.findViewById(R.id.txtAlertManTime); final int timeTrigger = c.getInt(6); final String[] services = c.getString(5).split(","); final StringBuilder sb = new StringBuilder(); for (String service : services) { if (sb.length() > 0) sb.append(", "); sb.append(service); } // Get the correct text to display, depending on plurality. txt.setText(Html.fromHtml(context.getResources().getQuantityString(R.plurals.alertmanager_time_text, timeTrigger == 0 ? 1 : timeTrigger, busStop, sb.toString(), timeTrigger))); break; default: break; } } } /** * Any Activities which host this Fragment must implement this interface to * handle navigation events. */ public static interface Callbacks { /** * This is called when it should be confirmed with the user that they * want to delete all alerts. */ public void onShowConfirmDeleteAllAlerts(); /** * This is called when it should be confirmed with the user that they * want to delete the proximity alert. */ public void onShowConfirmDeleteProximityAlert(); /** * This is called when it should be confirmed with the user that they * want to delete the time alert. */ public void onShowConfirmDeleteTimeAlert(); } }