对NotificationManager和方法notify的理解

NotificationManager myNotiManager=(NotificationManager)getSystemService(NOTIFICATION_SERVICE);
myNotiManager.notify(myNoti.flags,myNoti);
1，NOTIFICATION_SERVICE怎么得到的？
2，NotificationManager怎么产生的？

3，notify的动作又是怎么做到的？

从上面的函数：

@Overridepublic Object getSystemService(String name) {if (getBaseContext() == null) {throw new IllegalStateException("System services not available to Activities before onCreate()");}if (WINDOW_SERVICE.equals(name)) {return mWindowManager;} else if (SEARCH_SERVICE.equals(name)) {ensureSearchManager();return mSearchManager;}return super.getSystemService(name);}

继续跟入父类：getSystemService(name)

@Override public Object getSystemService(String name) {if (LAYOUT_INFLATER_SERVICE.equals(name)) {if (mInflater == null) {mInflater = LayoutInflater.from(mBase).cloneInContext(this);}return mInflater;}return mBase.getSystemService(name);}

继续跟入mBase.getSystemService(name)

在Context.java中文件，此函数的实现在ContextImp.java

public abstract Object getSystemService(String name);static {registerService(ACCESSIBILITY_SERVICE, new ServiceFetcher() {public Object getService(ContextImpl ctx) {return AccessibilityManager.getInstance(ctx);}});----------------------------registerService(NOTIFICATION_SERVICE, new ServiceFetcher() {public Object createService(ContextImpl ctx) {final Context outerContext = ctx.getOuterContext();return new NotificationManager(new ContextThemeWrapper(outerContext,Resources.selectSystemTheme(0,outerContext.getApplicationInfo().targetSdkVersion,com.android.internal.R.style.Theme_Dialog,com.android.internal.R.style.Theme_Holo_Dialog,com.android.internal.R.style.Theme_DeviceDefault_Dialog)),ctx.mMainThread.getHandler());}});----------------------------------registerService(WINDOW_SERVICE, new ServiceFetcher() {public Object getService(ContextImpl ctx) {return WindowManagerImpl.getDefault(ctx.mPackageInfo.mCompatibilityInfo);}});}

以上的静态块加载完成后会放到SYSTEM_SERVICE_MAP中，在通过开始的serviceName得到。

private static final HashMap<String, ServiceFetcher> SYSTEM_SERVICE_MAP =new HashMap<String, ServiceFetcher>();private static int sNextPerContextServiceCacheIndex = 0;private static void registerService(String serviceName, ServiceFetcher fetcher) {if (!(fetcher instanceof StaticServiceFetcher)) {fetcher.mContextCacheIndex = sNextPerContextServiceCacheIndex++;}SYSTEM_SERVICE_MAP.put(serviceName, fetcher);}

通过下面的函数对public abstract Object getSystemService(String name)真正实现 ContextImpl.java

@Overridepublic Object getSystemService(String name) {ServiceFetcher fetcher = SYSTEM_SERVICE_MAP.get(name);return fetcher == null ? null : fetcher.getService(this);}

很明显此时有NOTIFICATION_SERVICE即service != null,直接返回service；返回一个对应的Manager

public Object getService(ContextImpl ctx) {ArrayList<Object> cache = ctx.mServiceCache;Object service;synchronized (cache) {if (cache.size() == 0) {// Initialize the cache vector on first access.// At this point sNextPerContextServiceCacheIndex// is the number of potential services that are// cached per-Context.for (int i = 0; i < sNextPerContextServiceCacheIndex; i++) {cache.add(null);}} else {service = cache.get(mContextCacheIndex);if (service != null) {return service;  }}service = createService(ctx);cache.set(mContextCacheIndex, service);return service;}}

在看 myNotiManager.notify(myNoti.flags,myNoti);

public void notify(int id, Notification notification){notify(null, id, notification);}public void notify(String tag, int id, Notification notification){int[] idOut = new int[1];INotificationManager service = getService();String pkg = mContext.getPackageName();if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");try {service.enqueueNotificationWithTag(pkg, tag, id, notification, idOut);if (id != idOut[0]) {Log.w(TAG, "notify: id corrupted: sent " + id + ", got back " + idOut[0]);}} catch (RemoteException e) {}}static public INotificationManager getService(){if (sService != null) {return sService;}IBinder b = ServiceManager.getService("notification");sService = INotificationManager.Stub.asInterface(b);return sService;}public static IBinder getService(String name) {try {IBinder service = sCache.get(name);if (service != null) {return service;} else {return getIServiceManager().getService(name);}} catch (RemoteException e) {Log.e(TAG, "error in getService", e);}return null;}

那么 notification 这个key的IBinder有吗？

在Context.java里定义了：public static final String NOTIFICATION_SERVICE = "notification";
public static void initServiceCache(Map<String, IBinder> cache) {
if (sCache.size() != 0) {
throw new IllegalStateException("setServiceCache may only be called once");
}
sCache.putAll(cache);
}

上面的代码是在系统第一次启动时就加载的。

再回到

public void notify(String tag, int id, Notification notification){int[] idOut = new int[1];INotificationManager service = getService();   //这里已经得到实例String pkg = mContext.getPackageName();if (localLOGV) Log.v(TAG, pkg + ": notify(" + id + ", " + notification + ")");try {service.enqueueNotificationWithTag(pkg, tag, id, notification, idOut);if (id != idOut[0]) {Log.w(TAG, "notify: id corrupted: sent " + id + ", got back " + idOut[0]);}} catch (RemoteException e) {}}

在NotificationManagerService.java下实现 enqueueNotificationWithTag

public void enqueueNotificationWithTag(String pkg, String tag, int id, Notification notification,int[] idOut){enqueueNotificationInternal(pkg, Binder.getCallingUid(), Binder.getCallingPid(),tag, id, notification, idOut);}

最终到：

public void enqueueNotificationInternal(String pkg, int callingUid, int callingPid,String tag, int id, int priority, Notification notification, int[] idOut){checkIncomingCall(pkg);// Limit the number of notifications that any given package except the android// package can enqueue.  Prevents DOS attacks and deals with leaks.if (!"android".equals(pkg)) {synchronized (mNotificationList) {int count = 0;final int N = mNotificationList.size();for (int i=0; i<N; i++) {final NotificationRecord r = mNotificationList.get(i);if (r.pkg.equals(pkg)) {count++;if (count >= MAX_PACKAGE_NOTIFICATIONS) {Slog.e(TAG, "Package has already posted " + count+ " notifications.  Not showing more.  package=" + pkg);return;}}}}}// This conditional is a dirty hack to limit the logging done on//     behalf of the download manager without affecting other apps.if (!pkg.equals("com.android.providers.downloads")|| Log.isLoggable("DownloadManager", Log.VERBOSE)) {EventLog.writeEvent(EventLogTags.NOTIFICATION_ENQUEUE, pkg, id, tag,notification.toString());}if (pkg == null || notification == null) {throw new IllegalArgumentException("null not allowed: pkg=" + pkg+ " id=" + id + " notification=" + notification);}if (notification.icon != 0) {if (notification.contentView == null) {throw new IllegalArgumentException("contentView required: pkg=" + pkg+ " id=" + id + " notification=" + notification);}}synchronized (mNotificationList) {NotificationRecord r = new NotificationRecord(pkg, tag, id, callingUid, callingPid, priority,notification);NotificationRecord old = null;int index = indexOfNotificationLocked(pkg, tag, id);if (index < 0) {mNotificationList.add(r);} else {old = mNotificationList.remove(index);mNotificationList.add(index, r);// Make sure we don't lose the foreground service state.if (old != null) {notification.flags |=old.notification.flags&Notification.FLAG_FOREGROUND_SERVICE;}}// Ensure if this is a foreground service that the proper additional// flags are set.if ((notification.flags&Notification.FLAG_FOREGROUND_SERVICE) != 0) {notification.flags |= Notification.FLAG_ONGOING_EVENT| Notification.FLAG_NO_CLEAR;}if (notification.icon != 0) {StatusBarNotification n = new StatusBarNotification(pkg, id, tag,r.uid, r.initialPid, notification);n.priority = r.priority;if (old != null && old.statusBarKey != null) {r.statusBarKey = old.statusBarKey;long identity = Binder.clearCallingIdentity();try {mStatusBar.updateNotification(r.statusBarKey, n);}finally {Binder.restoreCallingIdentity(identity);}} else {long identity = Binder.clearCallingIdentity();try {r.statusBarKey = mStatusBar.addNotification(n);mAttentionLight.pulse();}finally {Binder.restoreCallingIdentity(identity);}}sendAccessibilityEvent(notification, pkg);} else {Slog.e(TAG, "Ignoring notification with icon==0: " + notification);if (old != null && old.statusBarKey != null) {long identity = Binder.clearCallingIdentity();try {mStatusBar.removeNotification(old.statusBarKey);}finally {Binder.restoreCallingIdentity(identity);}}}// If we're not supposed to beep, vibrate, etc. then don't.if (((mDisabledNotifications & StatusBarManager.DISABLE_NOTIFICATION_ALERTS) == 0)&& (!(old != null&& (notification.flags & Notification.FLAG_ONLY_ALERT_ONCE) != 0 ))&& mSystemReady) {final AudioManager audioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);// soundfinal boolean useDefaultSound =(notification.defaults & Notification.DEFAULT_SOUND) != 0;if (useDefaultSound || notification.sound != null) {Uri uri;if (useDefaultSound) {uri = Settings.System.DEFAULT_NOTIFICATION_URI;} else {uri = notification.sound;try {MediaPlayer mMediaPlayer = new MediaPlayer();mMediaPlayer.setDataSource(notification.sound.toString());} catch (Exception ex) {Slog.d(TAG, "default notification will be used");uri = Settings.System.DEFAULT_NOTIFICATION_URI;}}boolean looping = (notification.flags & Notification.FLAG_INSISTENT) != 0;int audioStreamType;if (notification.audioStreamType >= 0) {audioStreamType = notification.audioStreamType;} else {audioStreamType = DEFAULT_STREAM_TYPE;}mSoundNotification = r;// do not play notifications if stream volume is 0// (typically because ringer mode is silent).if (audioManager.getStreamVolume(audioStreamType) != 0) {long identity = Binder.clearCallingIdentity();try {mSound.play(mContext, uri, looping, audioStreamType);}finally {Binder.restoreCallingIdentity(identity);}}}// vibratefinal boolean useDefaultVibrate =(notification.defaults & Notification.DEFAULT_VIBRATE) != 0;if ((useDefaultVibrate || notification.vibrate != null)&& audioManager.shouldVibrate(AudioManager.VIBRATE_TYPE_NOTIFICATION)) {mVibrateNotification = r;mVibrator.vibrate(useDefaultVibrate ? DEFAULT_VIBRATE_PATTERN: notification.vibrate,((notification.flags & Notification.FLAG_INSISTENT) != 0) ? 0: -1);}}// this option doesn't shut off the lights// light// the most recent thing gets the lightmLights.remove(old);if (mLedNotification == old) {mLedNotification = null;}//Slog.i(TAG, "notification.lights="//        + ((old.notification.lights.flags & Notification.FLAG_SHOW_LIGHTS) != 0));if ((notification.flags & Notification.FLAG_SHOW_LIGHTS) != 0) {mLights.add(r);updateLightsLocked();} else {if (old != null&& ((old.notification.flags & Notification.FLAG_SHOW_LIGHTS) != 0)) {updateLightsLocked();}}}idOut[0] = id;}

以上就是对
NotificationManager myNotiManager=(NotificationManager)getSystemService(NOTIFICATION_SERVICE);
myNotiManager.notify(myNoti.flags,myNoti);
这2行代码的初略理解！

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