SystemUI默认去掉底部导航栏

一、背景

       在Android系统中，SystemUI负责管理系统的状态栏、导航栏等用户界面元素。若要在SystemUI中默认去掉底部导航栏，

可以通过以下几种方法实现：

1. 修改布局文件

在Android的SystemUI源代码中，底部导航栏的布局文件通常位于

com.android.systemui.statusbar.phone

包中，文件名可能为

NavigationBarView.xml

或其他与导航栏相关的布局文件。通过修改这些布局文件，可以隐藏底部导航栏。具体步骤包括：

• 使用Android Studio或其他IDE打开SystemUI项目。
• 导入Android的SystemUI源代码。
• 导航到与导航栏布局相关的文件。
• 修改布局文件中的代码以隐藏底部导航栏，例如通过设置visibility属性为GONE或INVISIBLE

frameworks\base\core\res\res\values\demins.xml

2. 编程方式隐藏

在SystemUI的Java代码中，可以通过编程方式控制底部导航栏的显示与隐藏。这通常涉及到对

NavigationBarController

或类似控制器的操作。例如，可以通过调用

setSystemUiVisibility

方法并传入适当的标志来隐藏导航栏，如

View.SYSTEM_UI_FLAG_HIDE_NAVIGATION

。但请注意，这种方法可能需要在应用层面而非系统层面实现，因为直接修改SystemUI的代码通常需要对Android系统进行深度定制。

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

3. 使用手势导航

主要核心代码:
framework/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java

二、改变状态栏或者其他系统UI的可见性

     setSystemUiVisibility(int visibility)：通过setSystemUiVisibility(int visibility)方法，可以改变状态栏或者其他系统UI的可见性。getWindow().getDecorView().setSystemUiVisibility(int visibility);

可供选择的参数：

View.SYSTEM_UI_FLAG_VISIBLE（默认模式，显示状态栏和导航栏）
View.SYSTEM_UI_FLAG_LOW_PROFILE（低调模式，隐藏不重要的状态栏图标，导航栏中相应的图标都变成了一个小点。点击状态栏或导航栏还原成正常的状态）
SYSTEM_UI_FLAG_HIDE_NAVIGATION（隐藏导航栏，点击屏幕任意区域，导航栏将重新出现，并且不会自动消失
SYSTEM_UI_FLAG_FULLSCREEN（隐藏状态栏，点击屏幕区域不会出现，需要从状态栏位置下拉才会出现）
SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION

三、三种方法去去掉底部导航栏

1、StatusBar中实现默认去掉底部导航栏

@Override
    public void start() {
        mGroupManager = Dependency.get(NotificationGroupManager.class);
        mGroupAlertTransferHelper = Dependency.get(NotificationGroupAlertTransferHelper.class);
        mVisualStabilityManager = Dependency.get(VisualStabilityManager.class);
        mNotificationLogger = Dependency.get(NotificationLogger.class);
        mRemoteInputManager = Dependency.get(NotificationRemoteInputManager.class);
        mNotificationListener =  Dependency.get(NotificationListener.class);
        mNotificationListener.registerAsSystemService();
        mNetworkController = Dependency.get(NetworkController.class);
        mUserSwitcherController = Dependency.get(UserSwitcherController.class);
        mScreenLifecycle = Dependency.get(ScreenLifecycle.class);
        mScreenLifecycle.addObserver(mScreenObserver);
        mWakefulnessLifecycle = Dependency.get(WakefulnessLifecycle.class);
        mWakefulnessLifecycle.addObserver(mWakefulnessObserver);
        mBatteryController = Dependency.get(BatteryController.class);
        mDataSaverController = Dependency.get(DataSaverController.class);
        mAssistManager = Dependency.get(AssistManager.class);
        mUiModeManager = mContext.getSystemService(UiModeManager.class);
        mLockscreenUserManager = Dependency.get(NotificationLockscreenUserManager.class);
        mGutsManager = Dependency.get(NotificationGutsManager.class);
        mMediaManager = Dependency.get(NotificationMediaManager.class);
        mEntryManager = Dependency.get(NotificationEntryManager.class);
        mNotificationInterruptionStateProvider =
                Dependency.get(NotificationInterruptionStateProvider.class);
        mViewHierarchyManager = Dependency.get(NotificationViewHierarchyManager.class);
        mForegroundServiceController = Dependency.get(ForegroundServiceController.class);
        mAppOpsController = Dependency.get(AppOpsController.class);
        mZenController = Dependency.get(ZenModeController.class);
        mKeyguardViewMediator = getComponent(KeyguardViewMediator.class);
        mColorExtractor = Dependency.get(SysuiColorExtractor.class);
        mDeviceProvisionedController = Dependency.get(DeviceProvisionedController.class);
        mNavigationBarController = Dependency.get(NavigationBarController.class);
        mBubbleController = Dependency.get(BubbleController.class);
        mBubbleController.setExpandListener(mBubbleExpandListener);
        mActivityIntentHelper = new ActivityIntentHelper(mContext);
        KeyguardSliceProvider sliceProvider = KeyguardSliceProvider.getAttachedInstance();
        if (sliceProvider != null) {
            sliceProvider.initDependencies(mMediaManager, mStatusBarStateController);
        } else {
            Log.w(TAG, "Cannot init KeyguardSliceProvider dependencies");
        }
 
        mColorExtractor.addOnColorsChangedListener(this);
        mStatusBarStateController.addCallback(this,
                SysuiStatusBarStateController.RANK_STATUS_BAR);
 
        mWindowManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
        mDreamManager = IDreamManager.Stub.asInterface(
                ServiceManager.checkService(DreamService.DREAM_SERVICE));
 
        /* UNISOC: Bug 1074234, 885650, Super power feature @{ */
        if(SprdPowerManagerUtil.SUPPORT_SUPER_POWER_SAVE){
            int mode = SprdPowerManagerUtil.getPowerSaveModeInternal();
            mPowerSaveMode = mode;
            curMode = mode;
        }
        /* @} */
 
        mDisplay = mWindowManager.getDefaultDisplay();
        mDisplayId = mDisplay.getDisplayId();
        updateDisplaySize();
 
        mVibrateOnOpening = mContext.getResources().getBoolean(
                R.bool.config_vibrateOnIconAnimation);
        mVibratorHelper = Dependency.get(VibratorHelper.class);
 
        DateTimeView.setReceiverHandler(Dependency.get(Dependency.TIME_TICK_HANDLER));
        putComponent(StatusBar.class, this);
 
        // start old BaseStatusBar.start().
        mWindowManagerService = WindowManagerGlobal.getWindowManagerService();
        mDevicePolicyManager = (DevicePolicyManager) mContext.getSystemService(
                Context.DEVICE_POLICY_SERVICE);
 
        mAccessibilityManager = (AccessibilityManager)
                mContext.getSystemService(Context.ACCESSIBILITY_SERVICE);
 
        mPowerManager = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
        mKeyguardUpdateMonitor = KeyguardUpdateMonitor.getInstance(mContext);
        mBarService = IStatusBarService.Stub.asInterface(
                ServiceManager.getService(Context.STATUS_BAR_SERVICE));
 
        mRecents = getComponent(Recents.class);
 
        mKeyguardManager = (KeyguardManager) mContext.getSystemService(Context.KEYGUARD_SERVICE);
 
        // Connect in to the status bar manager service
        mCommandQueue = getComponent(CommandQueue.class);
        mCommandQueue.addCallback(this);
 
        RegisterStatusBarResult result = null;
        try {
            result = mBarService.registerStatusBar(mCommandQueue);
        } catch (RemoteException ex) {
            ex.rethrowFromSystemServer();
        }
 
        createAndAddWindows(result);
 
        // Make sure we always have the most current wallpaper info.
        IntentFilter wallpaperChangedFilter = new IntentFilter(Intent.ACTION_WALLPAPER_CHANGED);
        mContext.registerReceiverAsUser(mWallpaperChangedReceiver, UserHandle.ALL,
                wallpaperChangedFilter, null /* broadcastPermission */, null /* scheduler */);
        mWallpaperChangedReceiver.onReceive(mContext, null);
 
        // Set up the initial notification state. This needs to happen before CommandQueue.disable()
        setUpPresenter();
 
        setSystemUiVisibility(mDisplayId, result.mSystemUiVisibility,
                result.mFullscreenStackSysUiVisibility, result.mDockedStackSysUiVisibility,
                0xffffffff, result.mFullscreenStackBounds, result.mDockedStackBounds,
                result.mNavbarColorManagedByIme);
        // StatusBarManagerService has a back up of IME token and it's restored here.
        setImeWindowStatus(mDisplayId, result.mImeToken, result.mImeWindowVis,
                result.mImeBackDisposition, result.mShowImeSwitcher);
 
        // Set up the initial icon state
        int numIcons = result.mIcons.size();
        for (int i = 0; i < numIcons; i++) {
            mCommandQueue.setIcon(result.mIcons.keyAt(i), result.mIcons.valueAt(i));
        }
 
 
        if (DEBUG) {
            Log.d(TAG, String.format(
                    "init: icons=%d disabled=0x%08x lights=0x%08x imeButton=0x%08x",
                    numIcons,
                    result.mDisabledFlags1,
                    result.mSystemUiVisibility,
                    result.mImeWindowVis));
        }
 
        IntentFilter internalFilter = new IntentFilter();
        internalFilter.addAction(BANNER_ACTION_CANCEL);
        internalFilter.addAction(BANNER_ACTION_SETUP);
        mContext.registerReceiver(mBannerActionBroadcastReceiver, internalFilter, PERMISSION_SELF,
                null);
 
        IWallpaperManager wallpaperManager = IWallpaperManager.Stub.asInterface(
                ServiceManager.getService(Context.WALLPAPER_SERVICE));
        try {
            wallpaperManager.setInAmbientMode(false /* ambientMode */, 0L /* duration */);
        } catch (RemoteException e) {
            // Just pass, nothing critical.
        }
 
        // end old BaseStatusBar.start().
 
        // Lastly, call to the icon policy to install/update all the icons.
        mIconPolicy = new PhoneStatusBarPolicy(mContext, mIconController);
        mSignalPolicy = new StatusBarSignalPolicy(mContext, mIconController);
 
        mUnlockMethodCache = UnlockMethodCache.getInstance(mContext);
        mUnlockMethodCache.addListener(this);
        startKeyguard();
 
        mKeyguardUpdateMonitor.registerCallback(mUpdateCallback);
        putComponent(DozeHost.class, mDozeServiceHost);
 
        mScreenPinningRequest = new ScreenPinningRequest(mContext);
        mFalsingManager = FalsingManagerFactory.getInstance(mContext);
 
        Dependency.get(ActivityStarterDelegate.class).setActivityStarterImpl(this);
 
        Dependency.get(ConfigurationController.class).addCallback(this);
 
        // set the initial view visibility
        Dependency.get(InitController.class).addPostInitTask(this::updateAreThereNotifications);
        int disabledFlags1 = result.mDisabledFlags1;
        int disabledFlags2 = result.mDisabledFlags2;
        Dependency.get(InitController.class).addPostInitTask(
                () -> setUpDisableFlags(disabledFlags1, disabledFlags2));
        // UNISOC: BUG 1156257 add screen resolution observer to control NavigationBarView
        mContext.getContentResolver().registerContentObserver(Settings.System.getUriFor(ACTION_SR_CHANGING),
                false, mScreenResolutionObserver);
 
        CommonUtils.setRegionOrLongshotMode(mContext.getContentResolver(), 0);
    }
 
    // ================================================================================
    // Constructing the view
    // ================================================================================
    protected void makeStatusBarView(@Nullable RegisterStatusBarResult result) {
        final Context context = mContext;
        updateDisplaySize(); // populates mDisplayMetrics
        updateResources();
        updateTheme();
 
        inflateStatusBarWindow(context);
        mStatusBarWindow.setService(this);
        mStatusBarWindow.setOnTouchListener(getStatusBarWindowTouchListener());
 
        // TODO: Deal with the ugliness that comes from having some of the statusbar broken out
        // into fragments, but the rest here, it leaves some awkward lifecycle and whatnot.
        mNotificationPanel = mStatusBarWindow.findViewById(R.id.notification_panel);
        mStackScroller = mStatusBarWindow.findViewById(R.id.notification_stack_scroller);
        mZenController.addCallback(this);
        NotificationListContainer notifListContainer = (NotificationListContainer) mStackScroller;
        mNotificationLogger.setUpWithContainer(notifListContainer);
 
        mNotificationIconAreaController = SystemUIFactory.getInstance()
                .createNotificationIconAreaController(context, this, mStatusBarStateController);
        inflateShelf();
        mNotificationIconAreaController.setupShelf(mNotificationShelf);
 
        Dependency.get(DarkIconDispatcher.class).addDarkReceiver(mNotificationIconAreaController);
        // Allow plugins to reference DarkIconDispatcher and StatusBarStateController
        Dependency.get(PluginDependencyProvider.class)
                .allowPluginDependency(DarkIconDispatcher.class);
        Dependency.get(PluginDependencyProvider.class)
                .allowPluginDependency(StatusBarStateController.class);
        FragmentHostManager.get(mStatusBarWindow)
                .addTagListener(CollapsedStatusBarFragment.TAG, (tag, fragment) -> {
                    CollapsedStatusBarFragment statusBarFragment =
                            (CollapsedStatusBarFragment) fragment;
                    statusBarFragment.initNotificationIconArea(mNotificationIconAreaController);
                    PhoneStatusBarView oldStatusBarView = mStatusBarView;
                    mStatusBarView = (PhoneStatusBarView) fragment.getView();
                    mStatusBarView.setBar(this);
                    mStatusBarView.setPanel(mNotificationPanel);
                    mStatusBarView.setScrimController(mScrimController);
 
                    // CollapsedStatusBarFragment re-inflated PhoneStatusBarView and both of
                    // mStatusBarView.mExpanded and mStatusBarView.mBouncerShowing are false.
                    // PhoneStatusBarView's new instance will set to be gone in
                    // PanelBar.updateVisibility after calling mStatusBarView.setBouncerShowing
                    // that will trigger PanelBar.updateVisibility. If there is a heads up showing,
                    // it needs to notify PhoneStatusBarView's new instance to update the correct
                    // status by calling mNotificationPanel.notifyBarPanelExpansionChanged().
                    if (mHeadsUpManager.hasPinnedHeadsUp()) {
                        mNotificationPanel.notifyBarPanelExpansionChanged();
                    }
                    mStatusBarView.setBouncerShowing(mBouncerShowing);
                    if (oldStatusBarView != null) {
                        float fraction = oldStatusBarView.getExpansionFraction();
                        boolean expanded = oldStatusBarView.isExpanded();
                        mStatusBarView.panelExpansionChanged(fraction, expanded);
                    }
 
                    HeadsUpAppearanceController oldController = mHeadsUpAppearanceController;
                    if (mHeadsUpAppearanceController != null) {
                        // This view is being recreated, let's destroy the old one
                        mHeadsUpAppearanceController.destroy();
                    }
                    mHeadsUpAppearanceController = new HeadsUpAppearanceController(
                            mNotificationIconAreaController, mHeadsUpManager, mStatusBarWindow);
                    mHeadsUpAppearanceController.readFrom(oldController);
                    mStatusBarWindow.setStatusBarView(mStatusBarView);
                    updateAreThereNotifications();
                    checkBarModes();
                }).getFragmentManager()
                .beginTransaction()
                .replace(R.id.status_bar_container, new CollapsedStatusBarFragment(),
                        CollapsedStatusBarFragment.TAG)
                .commit();
        mIconController = Dependency.get(StatusBarIconController.class);
 
        mHeadsUpManager = new HeadsUpManagerPhone(context, mStatusBarWindow, mGroupManager, this,
                mVisualStabilityManager);
        Dependency.get(ConfigurationController.class).addCallback(mHeadsUpManager);
        mHeadsUpManager.addListener(this);
        mHeadsUpManager.addListener(mNotificationPanel);
        mHeadsUpManager.addListener(mGroupManager);
        mHeadsUpManager.addListener(mGroupAlertTransferHelper);
        mHeadsUpManager.addListener(mVisualStabilityManager);
        mAmbientPulseManager.addListener(this);
        mAmbientPulseManager.addListener(mGroupManager);
        mAmbientPulseManager.addListener(mGroupAlertTransferHelper);
        mNotificationPanel.setHeadsUpManager(mHeadsUpManager);
        mGroupManager.setHeadsUpManager(mHeadsUpManager);
        mGroupAlertTransferHelper.setHeadsUpManager(mHeadsUpManager);
        mNotificationLogger.setHeadsUpManager(mHeadsUpManager);
        putComponent(HeadsUpManager.class, mHeadsUpManager);
 
        createNavigationBar(result);
 
        if (ENABLE_LOCKSCREEN_WALLPAPER) {
            mLockscreenWallpaper = new LockscreenWallpaper(mContext, this, mHandler);
        }
 
        mKeyguardIndicationController =
                SystemUIFactory.getInstance().createKeyguardIndicationController(mContext,
                        mStatusBarWindow.findViewById(R.id.keyguard_indication_area),
                        mStatusBarWindow.findViewById(R.id.lock_icon));
        mNotificationPanel.setKeyguardIndicationController(mKeyguardIndicationController);
 
        mAmbientIndicationContainer = mStatusBarWindow.findViewById(
                R.id.ambient_indication_container);
 
        // TODO: Find better place for this callback.
        mBatteryController.addCallback(new BatteryStateChangeCallback() {
            @Override
            public void onPowerSaveChanged(boolean isPowerSave) {
                mHandler.post(mCheckBarModes);
                if (mDozeServiceHost != null) {
                    mDozeServiceHost.firePowerSaveChanged(isPowerSave);
                }
            }
 
            @Override
            public void onBatteryLevelChanged(int level, boolean pluggedIn, boolean charging) {
                // noop
            }
        });
 
        mAutoHideController = Dependency.get(AutoHideController.class);
        mAutoHideController.setStatusBar(this);
 
        mLightBarController = Dependency.get(LightBarController.class);
 
        ScrimView scrimBehind = mStatusBarWindow.findViewById(R.id.scrim_behind);
        ScrimView scrimInFront = mStatusBarWindow.findViewById(R.id.scrim_in_front);
        mScrimController = SystemUIFactory.getInstance().createScrimController(
                scrimBehind, scrimInFront, mLockscreenWallpaper,
                (state, alpha, color) -> mLightBarController.setScrimState(state, alpha, color),
                scrimsVisible -> {
                    if (mStatusBarWindowController != null) {
                        mStatusBarWindowController.setScrimsVisibility(scrimsVisible);
                    }
                    if (mStatusBarWindow != null) {
                        mStatusBarWindow.onScrimVisibilityChanged(scrimsVisible);
                    }
                }, DozeParameters.getInstance(mContext),
                mContext.getSystemService(AlarmManager.class));
        mNotificationPanel.initDependencies(this, mGroupManager, mNotificationShelf,
                mHeadsUpManager, mNotificationIconAreaController, mScrimController);
        mDozeScrimController = new DozeScrimController(DozeParameters.getInstance(context));
 
        BackDropView backdrop = mStatusBarWindow.findViewById(R.id.backdrop);
        mMediaManager.setup(backdrop, backdrop.findViewById(R.id.backdrop_front),
                backdrop.findViewById(R.id.backdrop_back), mScrimController, mLockscreenWallpaper);
 
        // Other icons
        mVolumeComponent = getComponent(VolumeComponent.class);
 
        mNotificationPanel.setUserSetupComplete(mUserSetup);
        if (UserManager.get(mContext).isUserSwitcherEnabled()) {
            createUserSwitcher();
        }
 
        mNotificationPanel.setLaunchAffordanceListener(
                mStatusBarWindow::onShowingLaunchAffordanceChanged);
 
        // Set up the quick settings tile panel
        View container = mStatusBarWindow.findViewById(R.id.qs_frame);
        if (container != null) {
            FragmentHostManager fragmentHostManager = FragmentHostManager.get(container);
            ExtensionFragmentListener.attachExtensonToFragment(container, QS.TAG, R.id.qs_frame,
                    Dependency.get(ExtensionController.class)
                            .newExtension(QS.class)
                            .withPlugin(QS.class)
                            .withDefault(this::createDefaultQSFragment)
                            .build());
            mBrightnessMirrorController = new BrightnessMirrorController(mStatusBarWindow,
                    (visible) -> {
                        mBrightnessMirrorVisible = visible;
                        updateScrimController();
                    });
            fragmentHostManager.addTagListener(QS.TAG, (tag, f) -> {
                QS qs = (QS) f;
                if (qs instanceof QSFragment) {
                    mQSPanel = ((QSFragment) qs).getQsPanel();
                    mQSPanel.setBrightnessMirror(mBrightnessMirrorController);
                    mFooter = ((QSFragment) qs).getFooter();
                }
            });
        }
 
        mReportRejectedTouch = mStatusBarWindow.findViewById(R.id.report_rejected_touch);
        if (mReportRejectedTouch != null) {
            updateReportRejectedTouchVisibility();
            mReportRejectedTouch.setOnClickListener(v -> {
                Uri session = mFalsingManager.reportRejectedTouch();
                if (session == null) { return; }
 
                StringWriter message = new StringWriter();
                message.write("Build info: ");
                message.write(SystemProperties.get("ro.build.description"));
                message.write("\nSerial number: ");
                message.write(SystemProperties.get("ro.serialno"));
                message.write("\n");
 
                PrintWriter falsingPw = new PrintWriter(message);
                FalsingLog.dump(falsingPw);
                falsingPw.flush();
 
                startActivityDismissingKeyguard(Intent.createChooser(new Intent(Intent.ACTION_SEND)
                                .setType("*/*")
                                .putExtra(Intent.EXTRA_SUBJECT, "Rejected touch report")
                                .putExtra(Intent.EXTRA_STREAM, session)
                                .putExtra(Intent.EXTRA_TEXT, message.toString()),
                        "Share rejected touch report")
                                .addFlags(Intent.FLAG_ACTIVITY_NEW_TASK),
                        true /* onlyProvisioned */, true /* dismissShade */);
            });
        }
 
        PowerManager pm = (PowerManager) mContext.getSystemService(Context.POWER_SERVICE);
        if (!pm.isScreenOn()) {
            mBroadcastReceiver.onReceive(mContext, new Intent(Intent.ACTION_SCREEN_OFF));
        }
        mGestureWakeLock = pm.newWakeLock(PowerManager.SCREEN_BRIGHT_WAKE_LOCK,
                "GestureWakeLock");
        mVibrator = mContext.getSystemService(Vibrator.class);
        int[] pattern = mContext.getResources().getIntArray(
                R.array.config_cameraLaunchGestureVibePattern);
        mCameraLaunchGestureVibePattern = new long[pattern.length];
        for (int i = 0; i < pattern.length; i++) {
            mCameraLaunchGestureVibePattern[i] = pattern[i];
        }
 
        // receive broadcasts
        IntentFilter filter = new IntentFilter();
        filter.addAction(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
        filter.addAction(Intent.ACTION_SCREEN_OFF);
        filter.addAction(DevicePolicyManager.ACTION_SHOW_DEVICE_MONITORING_DIALOG);
        /* UNISOC: Bug 1074234, 885650, Super power feature @{ */
        if(SprdPowerManagerUtil.SUPPORT_SUPER_POWER_SAVE){
            filter.addAction(SprdPowerManagerUtil.ACTION_POWEREX_SAVE_MODE_CHANGED);
        }
        /* @} */
        context.registerReceiverAsUser(mBroadcastReceiver, UserHandle.ALL, filter, null, null);
 
        IntentFilter demoFilter = new IntentFilter();
        if (DEBUG_MEDIA_FAKE_ARTWORK) {
            demoFilter.addAction(ACTION_FAKE_ARTWORK);
        }
        demoFilter.addAction(ACTION_DEMO);
        context.registerReceiverAsUser(mDemoReceiver, UserHandle.ALL, demoFilter,
                android.Manifest.permission.DUMP, null);
 
        // listen for USER_SETUP_COMPLETE setting (per-user)
        mDeviceProvisionedController.addCallback(mUserSetupObserver);
        mUserSetupObserver.onUserSetupChanged();
 
        // disable profiling bars, since they overlap and clutter the output on app windows
        ThreadedRenderer.overrideProperty("disableProfileBars", "true");
 
        // Private API call to make the shadows look better for Recents
        ThreadedRenderer.overrideProperty("ambientRatio", String.valueOf(1.5f));
 
        /* UNISOC: Bug 1074234, 885650, Super power feature @{ */
        if(SprdPowerManagerUtil.SUPPORT_SUPER_POWER_SAVE && mNotificationPanel != null){
            int mode = SprdPowerManagerUtil.getPowerSaveModeInternal();
            if(mFooter != null){
                mFooter.setPowerSaveMode(mode);
            }
            if(mQSPanel != null){
                mQSPanel.setPowerSaveMode(mode);
            }
            if (mNotificationPanel != null){
                mNotificationPanel.setPowerSaveMode(mode);
            }
            /* UNISOC: Modify for bug974161 {@ */
            mNavigationBarController.setPowerSaveMode(mode);
            /* @} */
        }
        /* @} */
        /* UNISOC: Bug 1104465 add for screen pinning @{ */
        mScreenPinningNotify = new ScreenPinningNotify(mContext);
        /* @} */
    }
 
在makeStatusBarView(@Nullable RegisterStatusBarResult result)中的 createNavigationBar(result); 就是加载导航栏  直接注释掉就可以了

2、在DisplayPolicy.java中去掉底部导航栏

 public boolean hasNavigationBar() {
        return mHasNavigationBar;
    }
 
   /**
     * Return the display height available after excluding any screen
     * decorations that could never be removed in Honeycomb. That is, system bar or
     * button bar.
     */
    public int getNonDecorDisplayHeight(int fullWidth, int fullHeight, int rotation, int uiMode,
            DisplayCutout displayCutout) {
        int height = fullHeight;
        if (hasNavigationBar()) {
            final int navBarPosition = navigationBarPosition(fullWidth, fullHeight, rotation);
            if (navBarPosition == NAV_BAR_BOTTOM) {
                height -= getNavigationBarHeight(rotation, uiMode);
            }
        }
        if (displayCutout != null) {
            height -= displayCutout.getSafeInsetTop() + displayCutout.getSafeInsetBottom();
        }
        return height;
    }
 
   /**
     * Return the display width available after excluding any screen
     * decorations that could never be removed in Honeycomb. That is, system bar or
     * button bar.
     */
    public int getNonDecorDisplayWidth(int fullWidth, int fullHeight, int rotation, int uiMode,
            DisplayCutout displayCutout) {
        int width = fullWidth;
        if (hasNavigationBar()) {
            final int navBarPosition = navigationBarPosition(fullWidth, fullHeight, rotation);
            if (navBarPosition == NAV_BAR_LEFT || navBarPosition == NAV_BAR_RIGHT) {
                width -= getNavigationBarWidth(rotation, uiMode);
            }
        }
        if (displayCutout != null) {
            width -= displayCutout.getSafeInsetLeft() + displayCutout.getSafeInsetRight();
        }
        return width;
    }
 
根据hasNavigationBar()判断是否有导航栏来就是显示屏幕宽度和高度
 所以修改为:
 
    public boolean hasNavigationBar() {
      -  return mHasNavigationBar;
      + return false;
    }

3、默认隐藏导航栏

设置导航栏高度为0
路径:frameworks\base\core\res\res\values\demins.xml
<dimen name="navigation_bar_height">48dp</dimen>
navigation_bar_height 导航栏高度设置为0

4、修改完成记得执行快速编译命令

make snod

然后重启编译备，模拟器或者设备即可看到效果。

参考