Java tutorial
/* * Copyright (C) 2014 AChep@xda <artemchep@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 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. */ package com.achep.acdisplay.services; import android.app.Notification; import android.app.NotificationManager; import android.app.PendingIntent; import android.app.Service; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.content.IntentFilter; import android.os.IBinder; import android.support.v4.content.LocalBroadcastManager; import android.text.TextUtils; import android.util.Log; import com.achep.acdisplay.App; import com.achep.acdisplay.Build; import com.achep.acdisplay.R; import com.achep.acdisplay.activities.MainActivity; import com.achep.acdisplay.interfaces.IOnLowMemory; import java.util.HashMap; import java.util.Map; import java.util.Set; import java.util.concurrent.ConcurrentHashMap; /** * Created by achep on 26.05.14. * * @author Artem Chepurnoy */ // THIS CAN BE NOT SAFE!!! public class BathService extends Service { private static final String TAG = "BathService"; private static final String ACTION_ADD_SERVICE = TAG + ":add_service"; private static final String ACTION_REMOVE_SERVICE = TAG + ":remove_service"; private static final String EXTRA_SERVICE_CLASS = "class"; public static void startService(Context context, Class<? extends ChildService> clazz) { synchronized (monitor) { if (sCreated) { // Send broadcast intent to notify BathService // to start this child. Intent intent = new Intent(ACTION_ADD_SERVICE); intent.putExtra(EXTRA_SERVICE_CLASS, clazz); LocalBroadcastManager.getInstance(context).sendBroadcast(intent); } else if (!sServiceMap.containsKey(clazz)) { try { // Put empty child to host service and start host. sServiceMap.put(clazz, clazz.newInstance()); context.startService(new Intent(context, BathService.class)); } catch (InstantiationException | IllegalAccessException e) { throw new RuntimeException(e.getMessage()); // Should never happen } } } } public static void stopService(Context context, Class<? extends ChildService> clazz) { synchronized (monitor) { if (sCreated) { // Send broadcast intent to notify BathService // to stop this child. Intent intent = new Intent(ACTION_REMOVE_SERVICE); intent.putExtra(EXTRA_SERVICE_CLASS, clazz); LocalBroadcastManager.getInstance(context).sendBroadcast(intent); } else { // Service is not created, so I can handle hash map manually. sServiceMap.remove(clazz); } } } private static final ConcurrentHashMap<Class, ChildService> sServiceMap = new ConcurrentHashMap<>(2); private static final Object monitor = new Object(); private static boolean sCreated; private LocalBroadcastManager mLocalBroadcastManager; private NotificationManager mNotificationManager; private String mLanguage; private final HashMap<Class, ChildService> mMap = new HashMap<>(2); private final BroadcastReceiver mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { final String action = intent.getAction(); switch (action) { case ACTION_ADD_SERVICE: case ACTION_REMOVE_SERVICE: Class clazz = (Class) intent.getSerializableExtra(EXTRA_SERVICE_CLASS); fireService(clazz, action.equals(ACTION_ADD_SERVICE)); break; case Intent.ACTION_CONFIGURATION_CHANGED: String lang = getResources().getConfiguration().locale.getLanguage(); if (!TextUtils.equals(mLanguage, lang)) { mLanguage = lang; // Update the notification with new language set. updateNotification(); } break; } } }; @Override public void onCreate() { super.onCreate(); mNotificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE); mLanguage = getResources().getConfiguration().locale.getLanguage(); // Listen for the config changes to update notification just // once locale has changed. IntentFilter intentFilter = new IntentFilter(); intentFilter.addAction(Intent.ACTION_CONFIGURATION_CHANGED); registerReceiver(mReceiver, intentFilter); synchronized (monitor) { sCreated = true; // Register for add / remove service events. intentFilter = new IntentFilter(); intentFilter.addAction(ACTION_ADD_SERVICE); intentFilter.addAction(ACTION_REMOVE_SERVICE); mLocalBroadcastManager = LocalBroadcastManager.getInstance(this); mLocalBroadcastManager.registerReceiver(mReceiver, intentFilter); if (sServiceMap.isEmpty()) { stopSelf(); } else { // Init all children Set<Map.Entry<Class, ChildService>> set = sServiceMap.entrySet(); for (Map.Entry<Class, ChildService> entry : set) { ChildService child = entry.getValue(); child.setContext(this); child.onCreate(); mMap.put(entry.getKey(), child); } sServiceMap.clear(); startForeground(App.ID_NOTIFY_BATH, buildNotification()); } } } @Override public void onDestroy() { super.onDestroy(); unregisterReceiver(mReceiver); synchronized (monitor) { sCreated = false; mLocalBroadcastManager.unregisterReceiver(mReceiver); mLocalBroadcastManager = null; // Kill all children for (ChildService child : mMap.values()) { child.onDestroy(); } mMap.clear(); } // Make sure that notification does not exists. mNotificationManager.cancel(App.ID_NOTIFY_BATH); } private void updateNotification() { mNotificationManager.notify(App.ID_NOTIFY_BATH, buildNotification()); } /** * <p>NOT SYNCHRONIZED!</p> * Builds fresh notification with all {@link ChildService children services}'s * {@link com.achep.acdisplay.services.BathService.ChildService#getLabel() labels} in. * Content intent starts {@link com.achep.acdisplay.activities.MainActivity}. */ private Notification buildNotification() { boolean empty = true; StringBuilder builder = new StringBuilder(); String divider = getString(R.string.settings_multi_list_divider); for (ChildService child : mMap.values()) { if (!empty) { builder.append(divider); } builder.append(child.getLabel()); empty = false; } String contentText = builder.toString(); if (contentText.length() > 0) { contentText = contentText.charAt(0) + contentText.substring(1).toLowerCase(); } PendingIntent pendingIntent = PendingIntent.getActivity(this, App.ID_NOTIFY_BATH, new Intent(this, MainActivity.class), PendingIntent.FLAG_UPDATE_CURRENT); return new Notification.Builder(this).setContentTitle(getString(R.string.service_bath)) .setContentText(contentText).setContentIntent(pendingIntent).setSmallIcon(R.drawable.stat_acdisplay) .setPriority(Notification.PRIORITY_MIN).build(); } @Override public IBinder onBind(Intent intent) { return null; } @Override public void onLowMemory() { super.onLowMemory(); synchronized (monitor) { for (ChildService child : mMap.values()) { child.onLowMemory(); } } } private void fireService(Class clazz, boolean add) { synchronized (monitor) { boolean containsClazz = mMap.containsKey(clazz); if (containsClazz == add) { return; } if (add) { try { // Adding child to host service. ChildService child = (ChildService) clazz.newInstance(); child.setContext(BathService.this); child.onCreate(); mMap.put(clazz, child); } catch (InstantiationException | IllegalAccessException e) { throw new RuntimeException(e.getMessage()); // Should never happen } updateNotification(); return; } // Removing child from parent service. ChildService child = mMap.remove(clazz); child.onDestroy(); if (mMap.isEmpty()) { stopSelf(); } else { updateNotification(); } } } /** * Base for fake foreground service hosted in {@link com.achep.acdisplay.services.BathService}. * Call {@link BathService#startService(android.content.Context, Class)} to start this service, * and {@link BathService#stopService(android.content.Context, Class)} to stop. * * @author Artem Chepurnoy */ public abstract static class ChildService implements IOnLowMemory { private Context mContext; public ChildService() { if (Build.DEBUG) { Log.d(TAG, "Creating " + getClass().getSimpleName() + " service..."); } } void setContext(Context context) { mContext = context; } /** * Called when fake-service is attached to main one. * * @see android.app.Service#onCreate() */ public abstract void onCreate(); /** * Called when fake-service is detached from main one. * * @see android.app.Service#onDestroy() */ public abstract void onDestroy(); /** * {@inheritDoc} */ @Override public void onLowMemory() { /* placeholder */ } /** * @return The label of this service. */ public abstract String getLabel(); public Context getContext() { return mContext; } } }