Android导航栏功能项的显示与屏蔽介绍

    public ButtonDispatcher getScreenshotButton() {
        return mButtonDispatchers.get(R.id.screenshot);
    }
 
    public ButtonDispatcher getVolumeAddButton() {
        return mButtonDispatchers.get(R.id.volume_add);
    }
 
    public ButtonDispatcher getVolumeSubButton() {
        return mButtonDispatchers.get(R.id.volume_sub);
    }
 
    public ButtonDispatcher getRecentsButton() {
        return mButtonDispatchers.get(R.id.recent_apps);
    }
 
    public ButtonDispatcher getMenuButton() {
        return mButtonDispatchers.get(R.id.menu);
    }
 
    public ButtonDispatcher getBackButton() {
        return mButtonDispatchers.get(R.id.back);
    }
 
    public ButtonDispatcher getHomeButton() {
        return mButtonDispatchers.get(R.id.home);
    }
 
    public ButtonDispatcher getImeSwitchButton() {
        return mButtonDispatchers.get(R.id.ime_switcher);
    }
 
    public ButtonDispatcher getAccessibilityButton() {
        return mButtonDispatchers.get(R.id.accessibility_button);
    }

private void prepareNavigationBarView() {
        mNavigationBarView.reorient();
 
        ButtonDispatcher recentsButton = mNavigationBarView.getRecentsButton();
        recentsButton.setOnClickListener(this::onRecentsClick);
        recentsButton.setOnTouchListener(this::onRecentsTouch);
        recentsButton.setLongClickable(true);
        recentsButton.setOnLongClickListener(this::onLongPressBackRecents);
 
        ButtonDispatcher backButton = mNavigationBarView.getBackButton();
        backButton.setLongClickable(true);
        backButton.setOnLongClickListener(this::onLongPressBackRecents);
 
        ButtonDispatcher homeButton = mNavigationBarView.getHomeButton();
        homeButton.setOnTouchListener(this::onHomeTouch);
        homeButton.setOnLongClickListener(this::onHomeLongClick);
 
        ButtonDispatcher accessibilityButton =         mNavigationBarView.getAccessibilityButton();
        accessibilityButton.setOnClickListener(this::onAccessibilityClick);
        accessibilityButton.setOnLongClickListener(this::onAccessibilityLongClick);
        updateAccessibilityServicesState(mAccessibilityManager);
 
        ButtonDispatcher screenshotButton = mNavigationBarView.getScreenshotButton();
        screenshotButton.setOnClickListener(this:: screenshotClick);
        screenshotButton.setOnTouchListener(this:: screenshotTouch);
        boolean isShow=Settings.System.getInt(getContext().getContentResolver(), Settings.System.SCREENSHOT_BUTTON_SHOW, 1) == 1;
        if(isShow){
            screenshotButton.setVisibility(View.VISIBLE);
        }else{
            screenshotButton.setVisibility(View.GONE);
        }
 
        ButtonDispatcher volumeAddButton=mNavigationBarView.getVolumeAddButton();
        ButtonDispatcher volumeSubButton=mNavigationBarView.getVolumeSubButton();
        boolean isShowVolumeButton="true".equals(SystemProperties.get("ro.rk.systembar.voiceicon","true"));
        if(isShowVolumeButton){
            volumeAddButton.setVisibility(View.VISIBLE);
            volumeSubButton.setVisibility(View.VISIBLE);
        }else{
            volumeAddButton.setVisibility(View.GONE);
            volumeSubButton.setVisibility(View.GONE);
        }
        if (getContext().getResources().getConfiguration().smallestScreenWidthDp < 400) {
            volumeAddButton.setVisibility(View.GONE);
            volumeSubButton.setVisibility(View.GONE);
        }
    }

<string name="config_navBarLayout" translatable="false">left;volume_sub,back,home,recent,volume_add;right</string>

    <!-- Height of the status bar -->
    <dimen name="status_bar_height">0dp</dimen>