Android版本：8.1
创建Notification是很容易的，android8.0以后开始加入通知渠道NotificationChannel，然后在构造NotificationCompat.Builder的时候，指定要发送的渠道，最后调用NotificationManager.notify(id,notification)发送通知。
public void notify(int id, Notification notification)
{
notify(null, id, notification);
}
---------------
public void notify(String tag, int id, Notification notification)
{
notifyAsUser(tag, id, notification, new UserHandle(UserHandle.myUserId()));
}
---------------
public void notifyAsUser(String tag, int id, Notification notification, UserHandle user)
{
INotificationManager service = getService();
final Notification copy = Builder.maybeCloneStrippedForDelivery(notification, isLowRam);
...
try {
service.enqueueNotificationWithTag(pkg, mContext.getOpPackageName(), tag, id,
copy, user.getIdentifier());
} catch (RemoteException e) {
throw e.rethrowFromSystemServer();
}
}
-------------------
static public INotificationManager getService()
{
if (sService != null) {
return sService;
}
IBinder b = ServiceManager.getService("notification");
sService = INotificationManager.Stub.asInterface(b);
return sService;
}
获取了INotificationManager 远程接口对象，把Notification 给加入到队列中，
INotificationManager的远程对象是NotificationManagerService里的mservice，NotificationManagerService是系统服务。在开机启动的时候，Systemserver里和其他系统服务一起启动，最后注册到ServiceManager里。
publishBinderService(Context.NOTIFICATION_SERVICE, mService); //把service注册到Servicemanager里
----
private final IBinder mService = new INotificationManager.Stub(){
...
}
接着前面的，找到了enqueueNotificationWithTag
@Override
public void enqueueNotificationWithTag(String pkg, String opPkg, String tag, int id,
Notification notification, int userId) throws RemoteException {
enqueueNotificationInternal(pkg, opPkg, Binder.getCallingUid(),
Binder.getCallingPid(), tag, id, notification, userId);
}
------------
void enqueueNotificationInternal(final String pkg, final String opPkg, final int callingUid,
final int callingPid, final String tag, final int id, final Notification notification,
int incomingUserId) {
....处理notification包含的信息，通知渠道，优先级。。
mHandler.post(new EnqueueNotificationRunnable(userId, r));
}
把notification转换为NotificationRecord，并post给EnqueueNotificationRunnable，
EnqueueNotificationRunnable的run方法里。
@Override
public void run() {
synchronized (mNotificationLock) {
mEnqueuedNotifications.add(r);
scheduleTimeoutLocked(r);
...
mHandler.post(new PostNotificationRunnable(r.getKey()));
}
------------
@Override
public void run() {
synchronized (mNotificationLock) {
try {
NotificationRecord r = null;
int N = mEnqueuedNotifications.size();
NotificationRecord old = mNotificationsByKey.get(key);
final StatusBarNotification n = r.sbn;
final Notification notification = n.getNotification();
...
if (notification.getSmallIcon() != null) {
StatusBarNotification oldSbn = (old != null) ? old.sbn : null;
mListeners.notifyPostedLocked(n, oldSbn);
if (oldSbn == null || !Objects.equals(oldSbn.getGroup(), n.getGroup())) {
mHandler.post(new Runnable() {
@Override
public void run() {
mGroupHelper.onNotificationPosted(
n, hasAutoGroupSummaryLocked(n));
}
});
}
}
...
buzzBeepBlinkLocked(r);
}
------------
void buzzBeepBlinkLocked(NotificationRecord record) {
处理notification的 声音 震动和灯光闪烁
}
------------
public void notifyPostedLocked(StatusBarNotification sbn, StatusBarNotification oldSbn) {
发送给状态栏
mHandler.post(new Runnable() {
@Override
public void run() {
notifyPosted(info, sbnToPost, update);
}
});
}
↓
private void notifyPosted(final ManagedServiceInfo info,
final StatusBarNotification sbn, NotificationRankingUpdate rankingUpdate) {
final INotificationListener listener = (INotificationListener) info.service;
StatusBarNotificationHolder sbnHolder = new StatusBarNotificationHolder(sbn);
try {
listener.onNotificationPosted(sbnHolder, rankingUpdate);
} catch (RemoteException ex) {
Log.e(TAG, "unable to notify listener (posted): " + listener, ex);
}
}
INotificationListener是另一个远程接口对象
protected class NotificationListenerWrapper extends INotificationListener.Stub
------------
@Override
public void onNotificationPosted(IStatusBarNotificationHolder sbnHolder,
NotificationRankingUpdate update) {
SomeArgs args = SomeArgs.obtain();
args.arg1 = sbn;
args.arg2 = mRankingMap;
mHandler.obtainMessage(MyHandler.MSG_ON_NOTIFICATION_POSTED,
args).sendToTarget();
}
case MSG_ON_NOTIFICATION_POSTED: {
SomeArgs args = (SomeArgs) msg.obj;
StatusBarNotification sbn = (StatusBarNotification) args.arg1;
RankingMap rankingMap = (RankingMap) args.arg2;
args.recycle();
onNotificationPosted(sbn, rankingMap);
------------
public void onNotificationPosted(StatusBarNotification sbn, RankingMap rankingMap) {
onNotificationPosted(sbn);
}
public void onNotificationPosted(StatusBarNotification sbn) {
// optional
}
很意外，发现方法是空的，那调这么多有什么用？ 研究了一下发现，onNotificationPosted的这个方法属于的是
public abstract class NotificationListenerService extends Service {
NotificationListenerService 是个抽象方法，那很自然调用的时候会调用它的子类，
然后
public class NotificationListenerWithPlugins extends NotificationListenerService
但是找了一圈NotificationListenerWithPlugins ，没有onNotificationPosted，那只有继续找它的子类了，
后来发现，在Statusbar里有个匿名内部类实现了NotificationListenerService 的方法。
private final NotificationListenerWithPlugins mNotificationListener =
new NotificationListenerWithPlugins() {
...
@Override
public void onNotificationPosted(final StatusBarNotification sbn,
final RankingMap rankingMap) {
mHandler.post(new Runnable() {
@Override
public void run() {
...
if (isUpdate) {
updateNotification(sbn, rankingMap);
} else {
addNotification(sbn, rankingMap);
}
...
}
}
...
}
------------
public void addNotification(StatusBarNotification notification, RankingMap ranking)
throws InflationException {
Entry shadeEntry = createNotificationViews(notification);
boolean isHeadsUped = shouldPeek(shadeEntry);.
...
}
------------
protected NotificationData.Entry createNotificationViews(StatusBarNotification sbn)
throws InflationException {
NotificationData.Entry entry = new NotificationData.Entry(sbn);
Dependency.get(LeakDetector.class).trackInstance(entry);
entry.createIcons(mContext, sbn);
// Construct the expanded view.
inflateViews(entry, mStackScroller);
}
------------
protected void inflateViews(Entry entry, ViewGroup parent) {
new RowInflaterTask().inflate(mContext, parent, entry,
row -> {
bindRow(entry, pmUser, sbn, row);
updateNotification(entry, pmUser, sbn, row);
});
}
最后bindRow就是去构造通知栏的通知View，然后updateNotification就是去显示到状态栏。
private void updateNotification(Entry entry, PackageManager pmUser,
StatusBarNotification sbn, ExpandableNotificationRow row) {
...
row.updateNotification(entry);
}
------------
public void updateNotification(NotificationData.Entry entry) {
mEntry = entry;
mStatusBarNotification = entry.notification;
mNotificationInflater.inflateNotificationViews();
}
------------
public void inflateNotificationViews() {
inflateNotificationViews(FLAG_REINFLATE_ALL);
}
------------
void inflateNotificationViews(int reInflateFlags) {
...
StatusBarNotification sbn = mRow.getEntry().notification;
new AsyncInflationTask(sbn, reInflateFlags, mRow, mIsLowPriority,
mIsChildInGroup, mUsesIncreasedHeight, mUsesIncreasedHeadsUpHeight, mRedactAmbient,
mCallback, mRemoteViewClickHandler).execute();
}
使用了异步任务AsyncTask去完成布局
AsyncInflationTask
@Override
protected InflationProgress doInBackground(Void... params) {
return createRemoteViews(mReInflateFlags,
recoveredBuilder, mIsLowPriority, mIsChildInGroup,
mUsesIncreasedHeight, mUsesIncreasedHeadsUpHeight, mRedactAmbient,
packageContext);
}
------------
private static InflationProgress createRemoteViews(int reInflateFlags,
Notification.Builder builder, boolean isLowPriority, boolean isChildInGroup,
boolean usesIncreasedHeight, boolean usesIncreasedHeadsUpHeight, boolean redactAmbient,
Context packageContext) {
InflationProgress result = new InflationProgress();
isLowPriority = isLowPriority && !isChildInGroup;
if ((reInflateFlags & FLAG_REINFLATE_CONTENT_VIEW) != 0) {
result.newContentView = createContentView(builder, isLowPriority, usesIncreasedHeight);
}
if ((reInflateFlags & FLAG_REINFLATE_EXPANDED_VIEW) != 0) {
result.newExpandedView = createExpandedView(builder, isLowPriority);
}
if ((reInflateFlags & FLAG_REINFLATE_HEADS_UP_VIEW) != 0) {
result.newHeadsUpView = builder.createHeadsUpContentView(usesIncreasedHeadsUpHeight);
}
if ((reInflateFlags & FLAG_REINFLATE_PUBLIC_VIEW) != 0) {
result.newPublicView = builder.makePublicContentView();
}
if ((reInflateFlags & FLAG_REINFLATE_AMBIENT_VIEW) != 0) {
result.newAmbientView = redactAmbient ? builder.makePublicAmbientNotification()
: builder.makeAmbientNotification();
}
result.packageContext = packageContext;
return result;
}
到了这里，都是创建各种布局
比如createContentView
public RemoteViews createContentView() {
return createContentView(false /* increasedheight */ );
}
------------
public RemoteViews createContentView(boolean increasedHeight) {
if (mN.contentView != null && useExistingRemoteView()) {
return mN.contentView;
} else if (mStyle != null) {
final RemoteViews styleView = mStyle.makeContentView(increasedHeight);
if (styleView != null) {
return styleView;
}
}
return applyStandardTemplate(getBaseLayoutResource());
}
这里会去判断我们是否有在notification里添加style， 如果有不同的style，比如音乐播放器那种notification，就是自定义style，如果没有，那就用默认的layout。
private int getBaseLayoutResource() {
return R.layout.notification_template_material_base;
}
------------
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/status_bar_latest_event_content"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:tag="base" >
<include layout="@layout/notification_template_header" />
<LinearLayout
android:id="@+id/notification_main_column"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:layout_marginStart="@dimen/notification_content_margin_start"
android:layout_marginEnd="@dimen/notification_content_margin_end"
android:layout_marginTop="@dimen/notification_content_margin_top"
android:layout_marginBottom="@dimen/notification_content_margin_bottom"
android:orientation="vertical" >
<include layout="@layout/notification_template_part_line1" />
<include layout="@layout/notification_template_text" />
<include
android:layout_width="match_parent"
android:layout_height="@dimen/notification_progress_bar_height"
android:layout_marginTop="@dimen/notification_progress_margin_top"
layout="@layout/notification_template_progress" />
</LinearLayout>
<include layout="@layout/notification_template_right_icon" />
</FrameLayout>
原来这就是我们用的notification的布局内容。
private RemoteViews applyStandardTemplate(int resId) {
return applyStandardTemplate(resId, mParams.reset().fillTextsFrom(this));
}
private RemoteViews applyStandardTemplate(int resId, boolean hasProgress) {
return applyStandardTemplate(resId, mParams.reset().hasProgress(hasProgress)
.fillTextsFrom(this));
}
private RemoteViews applyStandardTemplate(int resId, StandardTemplateParams p) {
updateBackgroundColor(contentView);
bindNotificationHeader(contentView, p.ambient);
bindLargeIcon(contentView);
}
^_^ 后面全是布局绘画.
基本上这就是Notification从app到Framework再到SystemUI的流程，从notify到布局。
