安卓10系统如何增加双导航栏

mNavigationBarController2 = new BarController("NavigationBar2",
                displayId,
                View.NAVIGATION_BAR_TRANSIENT,
                View.NAVIGATION_BAR_UNHIDE,
                View.NAVIGATION_BAR_TRANSLUCENT,
                StatusBarManager.WINDOW_NAVIGATION_BAR,
                FLAG_TRANSLUCENT_NAVIGATION,
                View.NAVIGATION_BAR_TRANSPARENT);
2，在prepareAddWindowLw函数中添加导航栏2的窗口，通过YPE_NAVIGATION_BAR_PANEL类型添加，上层应用可以通过此类型调用，添加如下：
case TYPE_NAVIGATION_BAR_PANEL:
                mContext.enforceCallingOrSelfPermission(
                        android.Manifest.permission.STATUS_BAR_SERVICE,
                        "DisplayPolicy");
                if (mNavigationBar2 != null) {
                    if (mNavigationBar2.isAlive()) {
                        return WindowManagerGlobal.ADD_MULTIPLE_SINGLETON;
                    }
                }
                mNavigationBar2 = win;
                mNavigationBarController2.setWindow(win);
                mNavigationBarController2.setOnBarVisibilityChangedListener(
                        mNavBarVisibilityListener2, true);
                mDisplayContent.setInsetProvider(InsetsState.TYPE_NAVIGATION_BAR,
                        win, null /* frameProvider */);
                mDisplayContent.setInsetProvider(InsetsState.TYPE_BOTTOM_GESTURES, win,
                        (displayFrames, windowState, inOutFrame) -> {
                            inOutFrame.top -= mBottomGestureAdditionalInset;
                        });
                mDisplayContent.setInsetProvider(InsetsState.TYPE_LEFT_GESTURES, win,
                        (displayFrames, windowState, inOutFrame) -> {
                            inOutFrame.left = 0;
                            inOutFrame.top = 0;
                            inOutFrame.bottom = displayFrames.mDisplayHeight;
                            inOutFrame.right = displayFrames.mUnrestricted.left + mSideGestureInset;
                        });
                mDisplayContent.setInsetProvider(InsetsState.TYPE_RIGHT_GESTURES, win,
                        (displayFrames, windowState, inOutFrame) -> {
                            inOutFrame.left = displayFrames.mUnrestricted.right - mSideGestureInset;
                            inOutFrame.top = 0;
                            inOutFrame.bottom = displayFrames.mDisplayHeight;
                            inOutFrame.right = displayFrames.mDisplayWidth;
                        });
                mDisplayContent.setInsetProvider(InsetsState.TYPE_BOTTOM_TAPPABLE_ELEMENT, win,
                        (displayFrames, windowState, inOutFrame) -> {
                            if ((windowState.getAttrs().flags & FLAG_NOT_TOUCHABLE) != 0
                                    || mNavigationBarLetsThroughTaps) {
                                inOutFrame.setEmpty();
                            }
                        });
                if (DEBUG_LAYOUT) Slog.i(TAG, "NAVIGATION BAR PANEL: " + mNavigationBar2);
                break;
3，最后我们beginLayoutLw函数进行布局，如下：
private boolean layoutNavigationBar2(DisplayFrames displayFrames, int uiMode, boolean navVisible,
            boolean navTranslucent, boolean navAllowedHidden,
            boolean statusBarForcesShowingNavigation) {
        if (mNavigationBar2 == null) {
            return false;
        }

        final Rect navigationFrame = sTmpNavFrame;
        boolean transientNavBarShowing = mNavigationBarController2.isTransientShowing();
        // Force the navigation bar to its appropriate place and size. We need to do this directly,
        // instead of relying on it to bubble up from the nav bar, because this needs to change
        // atomically with screen rotations.
        final int rotation = displayFrames.mRotation;
        final int displayHeight = displayFrames.mDisplayHeight;
        final int displayWidth = displayFrames.mDisplayWidth;
        final Rect dockFrame = displayFrames.mDock;
        mNavigationBarPosition2 = NAV_BAR_RIGHT;
        
        final Rect cutoutSafeUnrestricted = sTmpRect;
        cutoutSafeUnrestricted.set(displayFrames.mUnrestricted);
        cutoutSafeUnrestricted.intersectUnchecked(displayFrames.mDisplayCutoutSafe);

        
            // Landscape screen; nav bar goes to the right.
            final int left = cutoutSafeUnrestricted.right
                    - getNavigationBarWidth(rotation, uiMode);
            navigationFrame.set(left, 0, displayFrames.mUnrestricted.right, displayHeight);
            displayFrames.mStable.right = displayFrames.mStableFullscreen.right = left;
            if (transientNavBarShowing) {
                mNavigationBarController2.setBarShowingLw(true);
            } else if (navVisible) {
                mNavigationBarController2.setBarShowingLw(true);
                dockFrame.right = displayFrames.mRestricted.right =
                        displayFrames.mRestrictedOverscan.right = left;
            } else {
                // We currently want to hide the navigation UI - unless we expanded the status bar.
                mNavigationBarController2.setBarShowingLw(statusBarForcesShowingNavigation);
            }
            if (navVisible && !navTranslucent && !navAllowedHidden
                    && !mNavigationBar2.isAnimatingLw()
                    && !mNavigationBarController2.wasRecentlyTranslucent()) {
                // If the nav bar is currently requested to be visible, and not in the process of
                // animating on or off, then we can tell the app that it is covered by it.
                displayFrames.mSystem.right = left;
            }
        

        // Make sure the content and current rectangles are updated to account for the restrictions
        // from the navigation bar.
        displayFrames.mCurrent.set(dockFrame);
        displayFrames.mVoiceContent.set(dockFrame);
        displayFrames.mContent.set(dockFrame);
        // And compute the final frame.
        sTmpRect.setEmpty();
        mNavigationBar2.getWindowFrames().setFrames(navigationFrame /* parentFrame */,
                navigationFrame /* displayFrame */, navigationFrame /* overscanFrame */,
                displayFrames.mDisplayCutoutSafe /* contentFrame */,
                navigationFrame /* visibleFrame */, sTmpRect /* decorFrame */,
                navigationFrame /* stableFrame */,
                displayFrames.mDisplayCutoutSafe /* outsetFrame */);
        mNavigationBar2.getWindowFrames().setDisplayCutout(displayFrames.mDisplayCutout);
        mNavigationBar2.computeFrameLw();
        mNavigationBarController2.setContentFrame(mNavigationBar2.getContentFrameLw());

        if (DEBUG_LAYOUT) Slog.i(TAG, "mNavigationBar2 frame: " + navigationFrame);
        return mNavigationBarController2.checkHiddenLw();
    }