刘海屏在刘海处也显示页面内容，在activity的onCreate加以下代码：
getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
}
if (Build.VERSION.SDK_INT >= 28) {
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.layoutInDisplayCutoutMode = WindowManager.LayoutParams.LAYOUT_IN_DISPLAY_CUTOUT_MODE_SHORT_EDGES;
getWindow().setAttributes(lp);
}
