Java tutorial
package com.mygeopay.wallet.ui; /* * Copyright 2012-2014 the original author or authors. * * 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/>. */ import com.mygeopay.wallet.Configuration; import com.mygeopay.wallet.ExchangeRatesProvider; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.net.ConnectivityManager; import android.net.Uri; import android.support.v4.content.CursorLoader; import android.content.SharedPreferences; import android.content.SharedPreferences.OnSharedPreferenceChangeListener; /** * @author Andreas Schildbach */ public final class ExchangeRateLoader extends CursorLoader implements OnSharedPreferenceChangeListener { private final Configuration config; private final String packageName; private final Context context; public ExchangeRateLoader(final Context context, final Configuration config, final String localSymbol, final String coinSymbol) { super(context, ExchangeRatesProvider.contentUriToCrypto(context.getPackageName(), localSymbol, false), null, ExchangeRatesProvider.KEY_CURRENCY_ID, new String[] { coinSymbol }, null); this.config = config; this.packageName = context.getPackageName(); this.context = context; } public ExchangeRateLoader(final Context context, final Configuration config, final String localSymbol) { super(context, ExchangeRatesProvider.contentUriToCrypto(context.getPackageName(), localSymbol, false), null, null, new String[] { null }, null); this.config = config; this.packageName = context.getPackageName(); this.context = context; } @Override protected void onStartLoading() { super.onStartLoading(); config.registerOnSharedPreferenceChangeListener(this); final IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction(ConnectivityManager.CONNECTIVITY_ACTION); intentFilter.addAction(Intent.ACTION_TIME_TICK); context.registerReceiver(broadcastReceiver, intentFilter); forceLoad(); } @Override protected void onStopLoading() { config.unregisterOnSharedPreferenceChangeListener(this); try { context.unregisterReceiver(broadcastReceiver); } catch (IllegalArgumentException e) { /* ignore */ } super.onStopLoading(); } @Override public void onSharedPreferenceChanged(final SharedPreferences sharedPreferences, final String key) { if (Configuration.PREFS_KEY_EXCHANGE_CURRENCY.equals(key)) onCurrencyChange(); } private void onCurrencyChange() { final String localCurrency = config.getExchangeCurrencyCode(); Uri newUri = ExchangeRatesProvider.contentUriToCrypto(packageName, localCurrency, false); setUri(newUri); forceLoad(); } private final BroadcastReceiver broadcastReceiver = new BroadcastReceiver() { private boolean hasConnectivity = true; @Override public void onReceive(final Context context, final Intent intent) { final String action = intent.getAction(); if (ConnectivityManager.CONNECTIVITY_ACTION.equals(action)) { hasConnectivity = !intent.getBooleanExtra(ConnectivityManager.EXTRA_NO_CONNECTIVITY, false); if (hasConnectivity) { forceLoad(); } } else if (Intent.ACTION_TIME_TICK.equals(action) && hasConnectivity) { forceLoad(); } } }; }