1.概述

遇到需求，QuickQSPanel首次下拉后展示快捷功能模块以后就是显示QuickQSPanel，而不展开QSPanel，接下来要从下滑手势下拉出状态栏分析功能实现。也就是直接是展开状态。

2、涉及核心类

frameworks\base\packages\SystemUI\src\com\android\systemui\statusbar\phone

Android12或者Android13frameworks\base\packages\SystemUI\src\com\android\systemui\statusbar\phone\NotificationPanelViewController.java
frameworks/base/packages/SystemUI/res/layout/status_bar_expanded.xmlAndroid10frameworks\base\packages\SystemUI\src\com\android\systemui\statusbar\phone\NotificationPanelViewController.java
frameworks/base/packages/SystemUI/res/layout/status_bar_expanded.xml

3、SystemUI下拉状态栏禁止QuickQSPanel展开的核心功能分析和实现

在系统SystemUI中，它主要负责反馈系统及应用状态并与用户保持大量的交互,systemui中主要核心布局控件为以下部分
在SystemUI中，QSPanel 创建是从 StatusBar#makeStatusBarView 开始的
接下来分析的核心功能和布局如下:
StatusBar：通知消息提示和状态展现
NavigationBar：返回，HOME，Recent
KeyGuard：锁屏模块可以看做单独的应用，提供基本的手机个人隐私保护
Recents：近期应用管理，以堆叠栈的形式展现。
Notification Panel：展示系统或应用通知内容。提供快速系统设置开关。
VolumeUI：来用展示或控制音量的变化：媒体音量、铃声音量与闹钟音量
截屏界面：长按电源键+音量下键后截屏，用以展示截取的屏幕照片/内容
PowerUI：主要处理和Power相关的事件，比如省电模式切换、电池电量变化和开关屏事件等。
RingtonePlayer：铃声播放
StackDivider：控制管理分屏
PipUI：提供对于画中画模式的管理

3.1 status_bar_expanded.xml下拉状态栏布局分析

<?xml version="1.0" encoding="utf-8"?>
<!--
**
** Copyright 2006, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**     http://www.apache.org/licenses/LICENSE-2.0
**
** Unless required by applicable law or agreed to in writing, software
** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
** limitations under the License.
*/
--><com.android.systemui.statusbar.phone.NotificationPanelViewxmlns:android="http://schemas.android.com/apk/res/android"xmlns:systemui="http://schemas.android.com/apk/res-auto"android:id="@+id/notification_panel"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@android:color/transparent"><FrameLayoutandroid:id="@+id/big_clock_container"android:layout_width="match_parent"android:layout_height="match_parent"android:visibility="gone" /><ViewStubandroid:id="@+id/keyguard_qs_user_switch_stub"android:layout="@layout/keyguard_qs_user_switch"android:layout_height="match_parent"android:layout_width="match_parent" /><includelayout="@layout/keyguard_bottom_area"android:visibility="gone" /><ViewStubandroid:id="@+id/keyguard_user_switcher_stub"android:layout="@layout/keyguard_user_switcher"android:layout_height="match_parent"android:layout_width="match_parent" /><include layout="@layout/status_bar_expanded_plugin_frame"/><include layout="@layout/dock_info_bottom_area_overlay" /><com.android.keyguard.LockIconViewandroid:id="@+id/lock_icon_view"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_gravity="center"><!-- Background protection --><ImageViewandroid:id="@+id/lock_icon_bg"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@drawable/fingerprint_bg"android:visibility="invisible"/><ImageViewandroid:id="@+id/lock_icon"android:layout_width="match_parent"android:layout_height="match_parent"android:padding="@dimen/lock_icon_padding"android:layout_gravity="center"android:scaleType="centerCrop"/></com.android.keyguard.LockIconView><com.android.systemui.statusbar.phone.NotificationsQuickSettingsContainerandroid:layout_width="match_parent"android:layout_height="match_parent"android:layout_gravity="@integer/notification_panel_layout_gravity"android:id="@+id/notification_container_parent"android:clipToPadding="false"android:clipChildren="false"><includelayout="@layout/keyguard_status_view"android:visibility="gone"/><include layout="@layout/dock_info_overlay" /><FrameLayoutandroid:id="@+id/qs_frame"android:layout="@layout/qs_panel"android:layout_width="@dimen/qs_panel_width"android:layout_height="0dp"android:clipToPadding="false"android:clipChildren="false"systemui:viewType="com.android.systemui.plugins.qs.QS"systemui:layout_constraintStart_toStartOf="parent"systemui:layout_constraintEnd_toEndOf="parent"systemui:layout_constraintTop_toTopOf="parent"systemui:layout_constraintBottom_toBottomOf="parent"/><androidx.constraintlayout.widget.Guidelineandroid:id="@+id/qs_edge_guideline"android:layout_width="wrap_content"android:layout_height="wrap_content"systemui:layout_constraintGuide_percent="0.5"android:orientation="vertical"/><com.android.systemui.statusbar.notification.stack.NotificationStackScrollLayoutandroid:id="@+id/notification_stack_scroller"android:layout_marginTop="@dimen/notification_panel_margin_top"android:layout_width="@dimen/notification_panel_width"android:layout_height="match_parent"android:layout_marginBottom="@dimen/close_handle_underlap"systemui:layout_constraintStart_toStartOf="parent"systemui:layout_constraintEnd_toEndOf="parent"/><include layout="@layout/ambient_indication"android:id="@+id/ambient_indication_container" /><include layout="@layout/photo_preview_overlay" /><includelayout="@layout/keyguard_status_bar"android:visibility="invisible" /><Buttonandroid:id="@+id/report_rejected_touch"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginTop="@dimen/status_bar_header_height_keyguard"android:text="@string/report_rejected_touch"android:visibility="gone" /><com.android.systemui.statusbar.phone.TapAgainViewandroid:id="@+id/shade_falsing_tap_again"android:layout_width="wrap_content"android:layout_height="wrap_content"systemui:layout_constraintLeft_toLeftOf="parent"systemui:layout_constraintRight_toRightOf="parent"systemui:layout_constraintBottom_toBottomOf="parent"android:layout_marginBottom="20dp"android:paddingHorizontal="16dp"android:minHeight="44dp"android:elevation="4dp"android:background="@drawable/rounded_bg_full"android:gravity="center"android:text="@string/tap_again"android:visibility="gone"/></com.android.systemui.statusbar.phone.NotificationsQuickSettingsContainer><FrameLayoutandroid:id="@+id/preview_container"android:layout_width="match_parent"android:layout_height="match_parent"></FrameLayout>
</com.android.systemui.statusbar.phone.NotificationPanelView>

在实现SystemUI下拉状态栏禁止QuickQSPanel展开的核心功能中，通过上述的分析得知，
从SystemUI中状态栏下拉的布局status_bar_expanded.xml的布局文件可以看到主要的下拉事件
是在NotificationPanelViewController.java中负责的，所以具体的下滑事件是在NotificationPanelViewController.java中处理的
所以接下来分析NotificationPanelViewController.java有关下拉状态栏的下滑展开事件

3.2 NotificationPanelViewController.java的下拉状态栏下滑事件分析

NotificationPanelViewController是一个以面板形式展示通知内容的主要视图控制器。它可以显示系统通知，
例如来自操作系统的警告、提醒或更新通知，以及来自其他应用程序的通知，如社交媒体应用或
即时消息应用发送的消息通知。通过notificationPanelViewController，用户可以方便地查看和管理收到的通知。

    public class NotificationPanelViewController extends PanelViewController { {@Overrideprotected TouchHandler createTouchHandler() {return new TouchHandler() {@Overridepublic boolean onInterceptTouchEvent(MotionEvent event) {if (mBlockTouches || mQsFullyExpanded && mQs.disallowPanelTouches()) {return false;}initDownStates(event);// Do not let touches go to shade or QS if the bouncer is visible,// but still let user swipe down to expand the panel, dismissing the bouncer.if (mStatusBar.isBouncerShowing()) {return true;}if (mBar.panelEnabled() && mHeadsUpTouchHelper.onInterceptTouchEvent(event)) {mMetricsLogger.count(COUNTER_PANEL_OPEN, 1);mMetricsLogger.count(COUNTER_PANEL_OPEN_PEEK, 1);return true;}if (!shouldQuickSettingsIntercept(mDownX, mDownY, 0)&& mPulseExpansionHandler.onInterceptTouchEvent(event)) {return true;}if (!isFullyCollapsed() && onQsIntercept(event)) {return true;}return super.onInterceptTouchEvent(event);}

在实现SystemUI下拉状态栏禁止QuickQSPanel展开的核心功能中，通过上述的分析得知，
在NotificationPanelViewController中的onInterceptTouchEvent(MotionEvent event) 手势下滑上滑事件的
处理，而具体处理下拉状态栏下滑事件的是在onQsIntercept(MotionEvent event)中继续处理的
接下来看下onQsIntercept(MotionEvent event)处理手势事件

 private boolean onQsIntercept(MotionEvent event) {int pointerIndex = event.findPointerIndex(mTrackingPointer);if (pointerIndex < 0) {pointerIndex = 0;mTrackingPointer = event.getPointerId(pointerIndex);}final float x = event.getX(pointerIndex);final float y = event.getY(pointerIndex);switch (event.getActionMasked()) {case MotionEvent.ACTION_DOWN:mIntercepting = true;mInitialTouchY = y;mInitialTouchX = x;initVelocityTracker();trackMovement(event);if (shouldQuickSettingsIntercept(mInitialTouchX, mInitialTouchY, 0)) {getParent().requestDisallowInterceptTouchEvent(true);}if (mQsExpansionAnimator != null) {onQsExpansionStarted();mInitialHeightOnTouch = mQsExpansionHeight;mQsTracking = true;mIntercepting = false;mNotificationStackScroller.cancelLongPress();}break;case MotionEvent.ACTION_POINTER_UP:final int upPointer = event.getPointerId(event.getActionIndex());if (mTrackingPointer == upPointer) {// gesture is ongoing, find a new pointer to trackfinal int newIndex = event.getPointerId(0) != upPointer ? 0 : 1;mTrackingPointer = event.getPointerId(newIndex);mInitialTouchX = event.getX(newIndex);mInitialTouchY = event.getY(newIndex);}break;case MotionEvent.ACTION_MOVE:final float h = y - mInitialTouchY;trackMovement(event);if (mQsTracking) {// Already tracking because onOverscrolled was called. We need to update here// so we don't stop for a frame until the next touch event gets handled in// onTouchEvent.setQsExpansion(h + mInitialHeightOnTouch);trackMovement(event);mIntercepting = false;return true;}if (Math.abs(h) > mTouchSlop && Math.abs(h) > Math.abs(x - mInitialTouchX)&& shouldQuickSettingsIntercept(mInitialTouchX, mInitialTouchY, h)) {mQsTracking = true;onQsExpansionStarted();notifyExpandingFinished();mInitialHeightOnTouch = mQsExpansionHeight;mInitialTouchY = y;mInitialTouchX = x;mIntercepting = false;mNotificationStackScroller.cancelLongPress();return true;}break;case MotionEvent.ACTION_CANCEL:case MotionEvent.ACTION_UP:trackMovement(event);if (mQsTracking) {flingQsWithCurrentVelocity(y,event.getActionMasked() == MotionEvent.ACTION_CANCEL);mQsTracking = false;}mIntercepting = false;break;}return false;}

在实现SystemUI下拉状态栏禁止QuickQSPanel展开的核心功能中，通过上述的分析得知，
在NotificationPanelViewController中onQsIntercept(MotionEvent event)的是具体处理下拉事件的方法
在case MotionEvent.ACTION_MOVE:中可以根据手势滑动的距离来设置下拉状态栏中的
QSPanel展开和收缩，通过setQsExpansion(h + mInitialHeightOnTouch);来根据手势滑动的
距离来设置QSPanel是否需要展开，所以具体看下setQsExpansion的相关代码

 private void setQsExpansion(float height) {// add core startif (mQs != null) return;//add core endheight = Math.min(Math.max(height, mQsMinExpansionHeight), mQsMaxExpansionHeight);mQsFullyExpanded = height == mQsMaxExpansionHeight && mQsMaxExpansionHeight != 0;if (height > mQsMinExpansionHeight && !mQsExpanded && !mStackScrollerOverscrolling) {setQsExpanded(true);} else if (height <= mQsMinExpansionHeight && mQsExpanded) {setQsExpanded(false);}mQsExpansionHeight = height;updateQsExpansion();requestScrollerTopPaddingUpdate(false /* animate */);updateHeaderKeyguardAlpha();if (mBarState == StatusBarState.SHADE_LOCKED|| mBarState == StatusBarState.KEYGUARD) {updateKeyguardBottomAreaAlpha();updateBigClockAlpha();}if (mBarState == StatusBarState.SHADE && mQsExpanded&& !mStackScrollerOverscrolling && mQsScrimEnabled) {mQsNavbarScrim.setAlpha(getQsExpansionFraction());}if (mAccessibilityManager.isEnabled()) {setAccessibilityPaneTitle(determineAccessibilityPaneTitle());}if (!mFalsingManager.isUnlockingDisabled() && mQsFullyExpanded&& mFalsingManager.shouldEnforceBouncer()) {mStatusBar.executeRunnableDismissingKeyguard(null, null /* cancelAction */,false /* dismissShade */, true /* afterKeyguardGone */, false /* deferred */);}if (mExpansionListener != null) {mExpansionListener.onQsExpansionChanged(mQsMaxExpansionHeight != 0? mQsExpansionHeight / mQsMaxExpansionHeight : 0);}if (DEBUG) {invalidate();}}

4、修改

在实现SystemUI下拉状态栏禁止QuickQSPanel展开的核心功能中，通过上述的分析得知，
在NotificationPanelViewController.java类中setQsExpansion(float height) 方法来设置下拉状态栏
QSPanel高度的方法中，根据高度判断是否需要展开收缩QSPanel,所以通过增加判断

if (mQs != null)return;

来去掉下滑展开QSPanel，就可以做到只显示QuickQSPanel，而
不用展开QSPanel，实现单次下拉状态栏，定制UI 就可以在QuickQSPanel中定制就可以了

 private void setQsExpansion(float height) {// mQs  不等于空直接复用if (mQs != null) return;// mQs 等于空新建height = Math.min(Math.max(height, mQsMinExpansionHeight), mQsMaxExpansionHeight);mQsFullyExpanded = height == mQsMaxExpansionHeight && mQsMaxExpansionHeight != 0;if (height > mQsMinExpansionHeight && !mQsExpanded && !mStackScrollerOverscrolling&& !mDozing) {setQsExpanded(true);} else if (height <= mQsMinExpansionHeight && mQsExpanded) {setQsExpanded(false);}mQsExpansionHeight = height;updateQsExpansion();requestScrollerTopPaddingUpdate(false /* animate */);updateHeaderKeyguardAlpha();if (mBarState == StatusBarState.SHADE_LOCKED || mBarState == KEYGUARD) {updateKeyguardBottomAreaAlpha();positionClockAndNotifications();updateBigClockAlpha();}if (mAccessibilityManager.isEnabled()) {mView.setAccessibilityPaneTitle(determineAccessibilityPaneTitle());}if (!mFalsingManager.isUnlockingDisabled() && mQsFullyExpanded&& mFalsingCollector.shouldEnforceBouncer()) {mStatusBar.executeRunnableDismissingKeyguard(null, null /* cancelAction */,false /* dismissShade */, true /* afterKeyguardGone */, false /* deferred */);}for (int i = 0; i < mExpansionListeners.size(); i++) {mExpansionListeners.get(i).onQsExpansionChanged(mQsMaxExpansionHeight != 0 ? mQsExpansionHeight / mQsMaxExpansionHeight : 0);}if (DEBUG) {mView.invalidate();}}