[android system] Hide system navigation bar

android 9.0 amlogic platform

修改  frameworks/base/core/res/res/values/dimens.xml

    <!-- The width used to calculate scale for full screen thumbnail on TV -->
    <integer name="thumbnail_width_tv">240</integer>
    <!-- The standard size (both width and height) of an application icon that
         will be displayed in the app launcher and elsewhere. -->
    <dimen name="app_icon_size">48dip</dimen>

    <dimen name="toast_y_offset">24dp</dimen>
    <!-- Height of the status bar -->
    <dimen name="status_bar_height">@dimen/status_bar_height_portrait</dimen>
    <!-- Height of the status bar in portrait -->
    <dimen name="status_bar_height_portrait">24dp</dimen>
    <!-- Height of the status bar in landscape -->
    <dimen name="status_bar_height_landscape">@dimen/status_bar_height_portrait</dimen>
    <!-- Height of area above QQS where battery/time go -->
    <dimen name="quick_qs_offset_height">48dp</dimen>
    <!-- Total height of QQS (quick_qs_offset_height + 128) -->
    <dimen name="quick_qs_total_height">176dp</dimen>
    <!-- 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="status_bar_height_portrait">24dp</dimen>

Change to

<dimen name="status_bar_height_portrait">0dp</dimen>