介绍
Bubbles（气泡）是Android Q中的一项新功能，借助气泡，用户可以轻松地在设备上的任何位置进行多任务处理。
更多官方描述请参考：气泡 | Android 开发者 。
发送通知
按正常的Notification的流程，从NotificationManager到NotificationManagerService不过多介绍，直接从NotificationManagerService开始。
/**
* Updates the flags for this notification to reflect whether it is a bubble or not.
*/
private void flagNotificationForBubbles(NotificationRecord r, String pkg, int userId,
NotificationRecord oldRecord) {
Notification notification = r.getNotification();
if (isNotificationAppropriateToBubble(r, pkg, userId, oldRecord)) {
notification.flags |= FLAG_BUBBLE;
} else {
notification.flags &= ~FLAG_BUBBLE;
}
}
/**
* @return whether the provided notification record is allowed to be represented as a bubble.
*/
private boolean isNotificationAppropriateToBubble(NotificationRecord r, String pkg, int userId,
NotificationRecord oldRecord) {
Notification notification = r.getNotification();
Notification.BubbleMetadata metadata = notification.getBubbleMetadata();
boolean intentCanBubble = metadata != null
&& canLaunchInActivityView(getContext(), metadata.getIntent(), pkg);
// Does the app want to bubble & is able to bubble
boolean canBubble = intentCanBubble
&& mPreferencesHelper.areBubblesAllowed(pkg, userId)
&& mPreferencesHelper.bubblesEnabled(r.sbn.getUser())
&& r.getChannel().canBubble()
&& !mActivityManager.isLowRamDevice();
// Is the app in the foreground?
final boolean appIsForeground =
mActivityManager.getPackageImportance(pkg) == IMPORTANCE_FOREGROUND;
// Is the notification something we'd allow to bubble?
// A call with a foreground service + person
ArrayList peopleList = notification.extras != null
? notification.extras.getParcelableArrayList(Notification.EXTRA_PEOPLE_LIST)
: null;
boolean isForegroundCall = CATEGORY_CALL.equals(notification.category)
&& (notification.flags & FLAG_FOREGROUND_SERVICE) != 0;
// OR message style (which always has a person) with any remote input
Class style = notification.getNotificationStyle();
boolean isMessageStyle = Notification.MessagingStyle.class.equals(style);
boolean notificationAppropriateToBubble =
(isMessageStyle && hasValidRemoteInput(notification))
|| (peopleList != null && !peopleList.isEmpty() && isForegroundCall);
// OR something that was previously a bubble & still exists
boolean bubbleUpdate = oldRecord != null
&& (oldRecord.getNotification().flags & FLAG_BUBBLE) != 0;
return canBubble && (notificationAppropriateToBubble || appIsForeground || bubbleUpdate);
}
/**
* Whether an intent is properly configured to display in an {@link android.app.ActivityView}.
*
* @param context the context to use.
* @param pendingIntent the pending intent of the bubble.
* @param packageName the notification package name for this bubble.
*/
// Keep checks in sync with BubbleController#canLaunchInActivityView.
@VisibleForTesting
protected boolean canLaunchInActivityView(Context context, PendingIntent pendingIntent,
String packageName) {
if (pendingIntent == null) {
Log.w(TAG, "Unable to create bubble -- no intent");
return false;
}
// Need escalated privileges to get the intent.
final long token = Binder.clearCallingIdentity();
Intent intent;
try {
intent = pendingIntent.getIntent();
} finally {
Binder.restoreCallingIdentity(token);
}
ActivityInfo info = intent != null
? intent.resolveActivityInfo(context.getPackageManager(), 0)
: null;
if (info == null) {
StatsLog.write(StatsLog.BUBBLE_DEVELOPER_ERROR_REPORTED, packageName,
BUBBLE_DEVELOPER_ERROR_REPORTED__ERROR__ACTIVITY_INFO_MISSING);
Log.w(TAG, "Unable to send as bubble -- couldn't find activity info for intent: "
+ intent);
return false;
}
if (!ActivityInfo.isResizeableMode(info.resizeMode)) {
StatsLog.write(StatsLog.BUBBLE_DEVELOPER_ERROR_REPORTED, packageName,
BUBBLE_DEVELOPER_ERROR_REPORTED__ERROR__ACTIVITY_INFO_NOT_RESIZABLE);
Log.w(TAG, "Unable to send as bubble -- activity is not resizable for intent: "
+ intent);
return false;
}
if (info.documentLaunchMode != DOCUMENT_LAUNCH_ALWAYS) {
StatsLog.write(StatsLog.BUBBLE_DEVELOPER_ERROR_REPORTED, packageName,
BUBBLE_DEVELOPER_ERROR_REPORTED__ERROR__DOCUMENT_LAUNCH_NOT_ALWAYS);
Log.w(TAG, "Unable to send as bubble -- activity is not documentLaunchMode=always "
+ "for intent: " + intent);
return false;
}
if ((info.flags & ActivityInfo.FLAG_ALLOW_EMBEDDED) == 0) {
Log.w(TAG, "Unable to send as bubble -- activity is not embeddable for intent: "
+ intent);
return false;
}
return true;
}
由于是新功能，所以源码里的注释给的挺多的样子，判断一条通知是不是需要以Bubble的形式显示，所有条件都在上面的方法里说明了：
- 必须设定有效的BubbleMetadata。
- BubbleMetadata中的PendingIntent必须是有效Activity，Activity必须设置resizeableActivity，documentLaunchMode，allowEmbedded等属性。
- 必须允许bubble功能（这点官方文档中已经说明，该功能必须在开发者选项中手动启用，启用后应用默认允许bubble，可在通知设置中关闭）。
- 以下三项满足一项或多项即可：
1.通知使用了MessagingStyle，并且设定了有效的action（官方文档中的描述是添加了Person对象？）；
2.通知为前台服务FLAG_FOREGROUND_SERVICE，类别为CATEGORY_CALL，并且添加了Person对象；
3.发送通知时该应用在前台运行。
如果判断成立，给通知加上FLAG_BUBBLE标记。
处理通知
frameworks → SystemUI 流程：
(frameworks) NotificationManager → NotificationManagerService → NotificationListenerService → (SystemUI) NotificationListener → NotificationEntryManager → BubbleController
Notification inflate view流程：
NotificationEntryManager.addNotificationInternal(...) → NotificationRowBinderImpl.inflateViews(...) →
SystemUI中有个类BubbleController，是用来处理bubble添加、删除以及在屏幕上显示状态等事件的。
BubbleController里面注册一些listeners，其中包括监听notification entry相关事件的listener，当有通知需要被添加进来时会回调对应的方法。
private final NotificationEntryListener mEntryListener = new NotificationEntryListener() {
@Override
public void onPendingEntryAdded(NotificationEntry entry) {
// 判断当前系统设置是否允许bubbles
if (!areBubblesEnabled(mContext)) {
return;
}
// 判断该entry是否能够以bubble状态显示，包括：应用是否允许bubbles，通知是否含有FLAG_BUBBLE标记，metadata是否有效等，
// 以及不被DND(勿扰)、snooze(打盹)、VR mode等设置覆盖.
if (mNotificationInterruptionStateProvider.shouldBubbleUp(entry)
// 看方法名就知道与NMS里的基本一致，在这边再判断一遍
&& canLaunchInActivityView(mContext, entry)) {
// 是否允许bubble与通知栏里的通知同时存在
updateShowInShadeForSuppressNotification(entry);
}
}
...
}