SystemUI导航栏

android13-release

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1、系统中参数项

1.1 相关开关属性

设置->系统->手势->系统导航->“三按钮”导航

• 设置中：“三按钮”导航
  packages/apps/Settings/src/com/android/settings/gestures/SystemNavigationGestureSettings.java
  packages/apps/Settings/res/values-zh-rCN/strings.xml
  <string name="legacy_navigation_title" msgid="7877402855994423727">"“三按钮”导航"</string>
  
  
• 默认导航栏模式：config_navBarInteractionMode
  frameworks/base/core/res/res/values/config.xml

   <!-- Controls the navigation bar interaction mode:0: 3 button mode (back, home, overview buttons)1: 2 button mode (back, home buttons + swipe up for overview)2: gestures only for back, home and overview --><integer name="config_navBarInteractionMode">0</integer><!-- Whether a software navigation bar should be shown. NOTE: in the future this may beautodetected from the Configuration. --><bool name="config_showNavigationBar">false</bool>

• Settings数据库中：adb shell settings get Secure navigation_mode
  frameworks/base/core/java/android/provider/Settings.java

/*** Navigation bar mode.*  0 = 3 button*  1 = 2 button*  2 = fully gestural* @hide*/
@Readable
public static final String NAVIGATION_MODE ="navigation_mode";

• prop属性"qemu.hw.mainkeys"：允许系统属性覆盖此设置。由仿真器使用。使用方法hasNavigationBar()
• 导航栏高度：navigation_bar_height
  frameworks/base/core/res/res/values/dimens.xml

   <!-- Height of the bottom navigation / system bar. --><dimen name="navigation_bar_height">48dp</dimen><!-- Height of the bottom navigation bar in portrait; often the same as @dimen/navigation_bar_height --><dimen name="navigation_bar_height_landscape">48dp</dimen>

2.2 属性设置代码

设置中显示判断：

• String NAV_BAR_MODE_3BUTTON_OVERLAY = "com.android.internal.systemui.navbar.threebutton";：
  /product/overlay/NavigationBarMode3Button/NavigationBarMode3ButtonOverlay.apk
• String NAV_BAR_MODE_2BUTTON_OVERLAY = "com.android.internal.systemui.navbar.twobutton";：
  /product/overlay/NavigationBarMode2Button/NavigationBarMode2ButtonOverlay.apk
• String NAV_BAR_MODE_GESTURAL_OVERLAY = "com.android.internal.systemui.navbar.gestural";：
  /product/overlay/NavigationBarModeGestural/NavigationBarModeGesturalOverlay.apk

packages/apps/Settings/src/com/android/settings/gestures/SystemNavigationPreferenceController.java

static boolean isOverlayPackageAvailable(Context context, String overlayPackage) {try {return context.getPackageManager().getPackageInfo(overlayPackage, 0) != null;} catch (PackageManager.NameNotFoundException e) {// Not found, just return unavailablereturn false;}
}

frameworks/base/packages/SystemUI/src/com/android/systemui/navigationbar/NavigationBar.java

private int mNavBarMode = NAV_BAR_MODE_3BUTTON;mNavBarMode = mNavigationModeController.addListener(mModeChangedListener);

frameworks/base/packages/SystemUI/src/com/android/systemui/navigationbar/NavigationModeController.java

private int getCurrentInteractionMode(Context context) {int mode = context.getResources().getInteger(com.android.internal.R.integer.config_navBarInteractionMode);if (DEBUG) {Log.d(TAG, "getCurrentInteractionMode: mode=" + mode+ " contextUser=" + context.getUserId());}return mode;
}public void updateCurrentInteractionMode(boolean notify) {mCurrentUserContext = getCurrentUserContext();int mode = getCurrentInteractionMode(mCurrentUserContext);mUiBgExecutor.execute(() ->Settings.Secure.putString(mCurrentUserContext.getContentResolver(),Secure.NAVIGATION_MODE, String.valueOf(mode)));if (DEBUG) {Log.d(TAG, "updateCurrentInteractionMode: mode=" + mode);dumpAssetPaths(mCurrentUserContext);}if (notify) {for (int i = 0; i < mListeners.size(); i++) {mListeners.get(i).onNavigationModeChanged(mode);}}
}

frameworks/base/services/core/java/com/android/server/wm/DisplayPolicy.java

if (mDisplayContent.isDefaultDisplay) {mHasStatusBar = true;mHasNavigationBar = mContext.getResources().getBoolean(R.bool.config_showNavigationBar);// Allow a system property to override this. Used by the emulator.// See also hasNavigationBar().String navBarOverride = SystemProperties.get("qemu.hw.mainkeys");if ("1".equals(navBarOverride)) {mHasNavigationBar = false;} else if ("0".equals(navBarOverride)) {mHasNavigationBar = true;}
} else {mHasStatusBar = false;mHasNavigationBar = mDisplayContent.supportsSystemDecorations();
}

2、设置中设置“三按钮”导航更新流程

2.1 属性资源覆盖叠加

OverlayManagerService 运行时资源叠加层 (RRO)
点击设置后，导航栏模式通过 OverlayManagerService 服务对 config_navBarInteractionMode 资源进行叠加，而settings的Secure表中navigation_mode属性只是记录模式。
frameworks/base/services/core/java/com/android/server/om/OverlayManagerService.java

资源叠加主要文件：config.xml
frameworks/base/core/res/res/values/config.xml
/product/overlay/NavigationBarMode3Button/NavigationBarMode3ButtonOverlay.apk
/product/overlay/NavigationBarMode2Button/NavigationBarMode2ButtonOverlay.apk
/product/overlay/NavigationBarModeGestural/NavigationBarModeGesturalOverlay.apk

• updateActivityManager(affectedPackages, userId)：发送受覆盖状态更改影响的所有目标包的配置更改事件。
• broadcastActionOverlayChanged(targets, userId)：发送覆盖包已更改广播ACTION_OVERLAY_CHANGED。

private void updateTargetPackagesLocked(@Nullable Set<PackageAndUser> updatedTargets) {if (CollectionUtils.isEmpty(updatedTargets)) {return;}persistSettingsLocked();final SparseArray<ArraySet<String>> userTargets = groupTargetsByUserId(updatedTargets);for (int i = 0, n = userTargets.size(); i < n; i++) {final ArraySet<String> targets = userTargets.valueAt(i);final int userId = userTargets.keyAt(i);final List<String> affectedPackages = updatePackageManagerLocked(targets, userId);if (affectedPackages.isEmpty()) {// The package manager paths are already up-to-date.continue;}FgThread.getHandler().post(() -> {// Send configuration changed events for all target packages that have been affected// by overlay state changes.updateActivityManager(affectedPackages, userId);// Do not send broadcasts for all affected targets. Overlays targeting the framework// or shared libraries may cause too many broadcasts to be sent at once.broadcastActionOverlayChanged(targets, userId);});}
}

2.2 SystemUI导航栏接收改变广播

mReceiver ：监听ACTION_OVERLAY_CHANGED广播
Secure.NAVIGATION_MODE：记录导航栏模式改变值
mListeners.get(i).onNavigationModeChanged(mode)：通知导航栏模式改变的ModeChangedListener监听

frameworks/base/packages/SystemUI/src/com/android/systemui/navigationbar/NavigationModeController.java

private BroadcastReceiver mReceiver = new BroadcastReceiver() {@Overridepublic void onReceive(Context context, Intent intent) {if (DEBUG) {Log.d(TAG, "ACTION_OVERLAY_CHANGED");}updateCurrentInteractionMode(true /* notify */);}
};public NavigationModeController(Context context,DeviceProvisionedController deviceProvisionedController,ConfigurationController configurationController,@UiBackground Executor uiBgExecutor,DumpManager dumpManager) {//... ...IntentFilter overlayFilter = new IntentFilter(ACTION_OVERLAY_CHANGED);overlayFilter.addDataScheme("package");overlayFilter.addDataSchemeSpecificPart("android", PatternMatcher.PATTERN_LITERAL);mContext.registerReceiverAsUser(mReceiver, UserHandle.ALL, overlayFilter, null, null);//... ...
}public void updateCurrentInteractionMode(boolean notify) {mCurrentUserContext = getCurrentUserContext();int mode = getCurrentInteractionMode(mCurrentUserContext);mUiBgExecutor.execute(() ->Settings.Secure.putString(mCurrentUserContext.getContentResolver(),Secure.NAVIGATION_MODE, String.valueOf(mode)));if (DEBUG) {Log.d(TAG, "updateCurrentInteractionMode: mode=" + mode);dumpAssetPaths(mCurrentUserContext);}if (notify) {for (int i = 0; i < mListeners.size(); i++) {mListeners.get(i).onNavigationModeChanged(mode);}}
}

2.3 SystemUI导航栏布局更新

NavigationModeController通知监听执行onNavigationModeChanged方法更新，最后 navBar.getView().updateStates()执行更新界面NavigationBarView：

• updateSlippery()：更新WindowManager.LayoutParams.FLAG_SLIPERY状态，具体取决于是否启用了向上滑动，或者通知是否在未处于动画状态的情况下完全打开。如果启用了slide，触摸事件将离开导航栏窗口并进入全屏应用程序/主页窗口，如果没有，则手势离开导航栏后，导航栏将收到取消的触摸事件。
• reloadNavIcons()：重新导入导航栏相关图片资源
• updateNavButtonIcons：更新界面导航栏图标、显示状态，及活动触摸区域

frameworks/base/packages/SystemUI/src/com/android/systemui/navigationbar/NavigationBarController.java

@Override
public void onNavigationModeChanged(int mode) {if (mNavMode == mode) {return;}final int oldMode = mNavMode;mNavMode = mode;updateAccessibilityButtonModeIfNeeded();mHandler.post(() -> {// create/destroy nav bar based on nav mode only in unfolded stateif (oldMode != mNavMode) {updateNavbarForTaskbar();}for (int i = 0; i < mNavigationBars.size(); i++) {NavigationBar navBar = mNavigationBars.valueAt(i);if (navBar == null) {continue;}navBar.getView().updateStates();}});
}

frameworks/base/packages/SystemUI/src/com/android/systemui/navigationbar/NavigationBarView.java

public void updateStates() {if (mNavigationInflaterView != null) {// Reinflate the navbar if needed, no-op unless the swipe up state changesmNavigationInflaterView.onLikelyDefaultLayoutChange();}updateSlippery();reloadNavIcons();updateNavButtonIcons();WindowManagerWrapper.getInstance().setNavBarVirtualKeyHapticFeedbackEnabled(!mShowSwipeUpUi);getHomeButton().setAccessibilityDelegate(mShowSwipeUpUi ? mQuickStepAccessibilityDelegate : null);
}

2.4 时序图