引言
今天我们主要讲的是SystemUI状态栏里面另一个常见的icons——notification icons，该icons主要用于显示app或者framework发送的各种notification icon，表示当前有新的通知来了，需要下拉通知栏进行查看，以达到提示用户的目的。
正文
本文主要从两个方面讲述下notification icon功能，主要分为初始化流程和通知icon显示流程
话不多说，我们开始吧。
初始化流程
首先我们看下状态栏的布局文件 status_bar.xml
<!-- The alpha of this area is controlled from both PhoneStatusBarTransitions and
PhoneStatusBar (DISABLE_NOTIFICATION_ICONS). -->
<com.android.systemui.statusbar.AlphaOptimizedFrameLayout
android:id="@+id/notification_icon_area"
android:layout_width="0dip"
android:layout_height="match_parent"
android:layout_weight="1"
android:orientation="horizontal" />
<com.android.keyguard.AlphaOptimizedLinearLayout android:id="@+id/system_icon_area"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:orientation="horizontal"
>
我们今天讲的notification icons就是这个 android:id="@+id/notification_icon_area" 了。
同样它最外层是一个AlphaOptimizedFrameLayout控件,前文已经说过类似的了,
SystemUI之状态栏status icon加载流程
该控件实现了hasOverlappingRendering()方法,该方法用来标记当前view是否存在过度绘制。
接下来我们看下SystemUI是怎么加载这个AlphaOptimizedFrameLayout
CollapsedStatusBarFragment.java
public void initNotificationIconArea(NotificationIconAreaController
notificationIconAreaController) {
ViewGroup notificationIconArea = mStatusBar.findViewById(R.id.notification_icon_area);
mNotificationIconAreaInner =
notificationIconAreaController.getNotificationInnerAreaView();
if (mNotificationIconAreaInner.getParent() != null) {
((ViewGroup) mNotificationIconAreaInner.getParent())
.removeView(mNotificationIconAreaInner);
}
notificationIconArea.addView(mNotificationIconAreaInner);
// Default to showing until we know otherwise.
showNotificationIconArea(false);
}
NotificationIconAreaController.java
/**
* Initializes the views that will represent the notification area.
*/
protected void initializeNotificationAreaViews(Context context) {
reloadDimens(context);
LayoutInflater layoutInflater = LayoutInflater.from(context);
mNotificationIconArea = inflateIconArea(layoutInflater);
mNotificationIcons = (NotificationIconContainer) mNotificationIconArea.findViewById(
R.id.notificationIcons);
mNotificationScrollLayout = mStatusBar.getNotificationScrollLayout();
}
protected View inflateIconArea(LayoutInflater inflater) {
return inflater.inflate(R.layout.notification_icon_area, null);
}
如上,我们就找到了初始化的地方,主要是通过inflate这个R.layout.notification_icon_area文件,通过addView的方式添加到了AlphaOptimizedFrameLayout,下面就是看下R.layout.notification_icon_area这个文件了
<com.android.keyguard.AlphaOptimizedLinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/notification_icon_area_inner"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<com.android.systemui.statusbar.phone.NotificationIconContainer
android:id="@+id/notificationIcons"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_alignParentStart="true"
android:gravity="center_vertical"
android:orientation="horizontal"/>
</com.android.keyguard.AlphaOptimizedLinearLayout>
/**
* A container for notification icons. It handles overflowing icons properly and positions them
* correctly on the screen.
*/
public class NotificationIconContainer extends AlphaOptimizedFrameLayout {}
从备注就能够看出来,这个就是所有notification icons的父控件,所有icons最后都是添加到这里面来的,
好了，到这里我们的第一部分初始化流程就讲完了。
通知icon显示流程
首先我们需要看下notification生成的地方
StatusBar.java
public void onNotificationPosted(final StatusBarNotification sbn,
final RankingMap rankingMap) {
if (isUpdate) {
updateNotification(sbn, rankingMap);
} else {
addNotification(sbn, rankingMap);
}
}
public void addNotification(StatusBarNotification notification, RankingMap ranking)
throws InflationException {
String key = notification.getKey();
if (DEBUG) Log.d(TAG, "addNotification key=" + key);
mNotificationData.updateRanking(ranking);
Entry shadeEntry = createNotificationViews(notification);
protected NotificationData.Entry createNotificationViews(StatusBarNotification sbn)
throws InflationException {
if (DEBUG) {
Log.d(TAG, "createNotificationViews(notification=" + sbn);
}
NotificationData.Entry entry = new NotificationData.Entry(sbn);
Dependency.get(LeakDetector.class).trackInstance(entry);
entry.createIcons(mContext, sbn);
// Construct the expanded view.
inflateViews(entry, mStackScroller);
return entry;
}
}
层层调用之后,最后会通过entry.createIcons(mContext, sbn)生成notification icon,然后存放在NotificationData里面,感兴趣的可以看下entry.createIcons(mContext, sbn), 该函数里面主要生成了一个StatusBarIconView对象,这个就是最终显示在状态栏的icon。
notification生成的过程大致就是通过inflateViews(entry, mStackScroller)--->AsyncInflationTask处理加载然后生成ExpandableNotificationRow等的信息,最后通过StatusBar.java
@Override
public void onAsyncInflationFinished(Entry entry) {
mPendingNotifications.remove(entry.key);
// If there was an async task started after the removal, we don't want to add it back to
// the list, otherwise we might get leaks.
boolean isNew = mNotificationData.get(entry.key) == null;
if (isNew && !entry.row.isRemoved()) {
addEntry(entry);
} else if (!isNew && entry.row.hasLowPriorityStateUpdated()) {
mVisualStabilityManager.onLowPriorityUpdated(entry);
updateNotificationShade();// 此处完成添加
}
entry.row.setLowPriorityStateUpdated(false);
}
private void updateNotificationShade() {
................................................
for (int i=0; i<toShow.size(); i++) {
View v = toShow.get(i);
if (v.getParent() == null) {
mVisualStabilityManager.notifyViewAddition(v);
mStackScroller.addView(v);
}
}
................................................
// Let's also update the icons
mNotificationIconAreaController.updateNotificationIcons(mNotificationData);//添加notification icons
}
updateNotificationShade这个函数回调完成view的添加,这个函数先是把inflate出来的通知,添加到NotificationScrollLayout里面,然后再添加notification icon,接下来我们就看下updateNotificationIcons里面的逻辑了。
NotificationIconAreaController.java
private NotificationIconContainer mNotificationIcons;
/**
* Updates the notifications with the given list of notifications to display.
*/
public void updateNotificationIcons(NotificationData notificationData) {
updateIconsForLayout(notificationData, entry -> entry.icon, mNotificationIcons,
false /* showAmbient */);// 添加status bar notification icon
updateIconsForLayout(notificationData, entry -> entry.expandedIcon, mShelfIcons,
NotificationShelf.SHOW_AMBIENT_ICONS);// 添加 notification self icon
applyNotificationIconsTint();
}
主要的添加动作就在updateIconsForLayout这个函数中了
private void updateIconsForLayout(NotificationData notificationData,
Function<NotificationData.Entry, StatusBarIconView> function,
NotificationIconContainer hostLayout, boolean showAmbient) {
ArrayList<StatusBarIconView> toShow = new ArrayList<>(
mNotificationScrollLayout.getChildCount());
// Filter out ambient notifications and notification children.
for (int i = 0; i < mNotificationScrollLayout.getChildCount(); i++) {
View view = mNotificationScrollLayout.getChildAt(i);
if (view instanceof ExpandableNotificationRow) {
NotificationData.Entry ent = ((ExpandableNotificationRow) view).getEntry();
if (shouldShowNotificationIcon(ent, notificationData, showAmbient)) {
toShow.add(function.apply(ent));
}
}
}
......................................
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final FrameLayout.LayoutParams params = generateIconLayoutParams();
for (int i = 0; i < toShow.size(); i++) {
View v = toShow.get(i);
// The view might still be transiently added if it was just removed and added again
hostLayout.removeTransientView(v);
if (v.getParent() == null) {
hostLayout.addView(v, i, params);
}
}
}
首先从mNotificationScrollLayout取出NotificationData,然后把NotificationData存放的StatusBarIconView取出添加到toShow里面,最后遍历添加到NotificationIconContainer中,这样就完成了往NotificationIconContainer添加icon的过程。
到这里，notification icon加载流程已经讲完，后面有时间还会讲下signal icon的加载流程，敬请关注。
如有什么问题欢迎指正。
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