直播平台软件开发，Android SystemUI 导航栏动态显示隐藏

1、导航栏创建加载及隐藏：

<br> frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/StatusBar.java<br>    ...<br>        try {<br>            // boolean showNav = mWindowManagerService.hasNavigationBar();<br>            // 添加自定义控制状态栏的 Settings.system 属性值,控制初始化时是否创建状态栏<br>            boolean showNav = Settings.system.getInt(mContext.getContentResolver(), "nav_bar_mode", 0) == 0;<br>            // 注册属性值变化监听<br>            mContext.getContentResolver().registerContentObserver(<br>                    Settings.System.getUriFor("nav_bar_mode"), false, new SettingsObserver(mHandler), UserHandle.USER_ALL);<br> <br>            if (DEBUG) Log.v(TAG, "hasNavigationBar=" + showNav);<br>            if (showNav) {<br>                createNavigationBar();<br>            }<br>        } catch (RemoteException ex) {<br>            // no window manager? good luck with that<br>        }<br>    ...<br> <br>    // 自定义 nav_bar_mode 属性值的监听<br>    private final class SettingsObserver extends ContentObserver {<br>        public SettingsObserver(Handler handler) {<br>            super(handler);<br>        }<br> <br>        @Override<br>        public void onChange(boolean selfChange, Uri uri) {<br>            int navMode = Settings.Secure.getInt(mContext.getContentResolver(), "nav_bar_mode", 0);<br>            Log.i("TAG", "navMode = " + navMode);<br>            switch (navMode) {<br>                case 0:<br>                    createNavigationBar();<br>                    break;<br> <br>                case 1:<br>                    mContext.getSystemService(WindowManager.class).removeView(mNavigationBarView);<br>                    break;<br> <br>                default:<br>                    Log.w(TAG, "Unknown mode");<br>                    break;<br>            }<br>        }<br>    }

这里主要了解导航栏的加载是由系统的 WindowManager 加载，通过addView进行加载显示，所以我们也可以通过 removeView 去进行删除隐藏。

2、加载 view 的源码：

<br>frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/NavigationBarFragment.java<br>    public static View create(Context context, FragmentListener listener) {<br>        WindowManager.LayoutParams lp = new WindowManager.LayoutParams(<br>                LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT,<br>                WindowManager.LayoutParams.TYPE_NAVIGATION_BAR,<br>                WindowManager.LayoutParams.FLAG_TOUCHABLE_WHEN_WAKING<br>                        | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE<br>                        | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL<br>                        | WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH<br>                        | WindowManager.LayoutParams.FLAG_SPLIT_TOUCH<br>                        | WindowManager.LayoutParams.FLAG_SLIPPERY,<br>                PixelFormat.TRANSLUCENT);<br>        lp.token = new Binder();<br>        lp.setTitle("NavigationBar");<br>        lp.accessibilityTitle = context.getString(R.string.nav_bar);<br>        lp.windowAnimations = 0;<br>        View navigationBarView = LayoutInflater.from(context).inflate(<br>                R.layout.navigation_bar_window, null);<br>        if (DEBUG) Log.v(TAG, "addNavigationBar: about to add " + navigationBarView);<br>        if (navigationBarView == null) return null;<br>        context.getSystemService(WindowManager.class).addView(navigationBarView, lp);<br>        FragmentHostManager fragmentHost = FragmentHostManager.get(navigationBarView);<br>        NavigationBarFragment fragment = new NavigationBarFragment();<br>        fragmentHost.getFragmentManager().beginTransaction()<br>                .replace(R.id.navigation_bar_frame, fragment, TAG)<br>                .commit();<br>        fragmentHost.addTagListener(TAG, listener);<br>        return navigationBarView;<br>    }