question: private static void addMarginTopToContentChild ( View mContentChild , int statusBarHeight ) { if ( mContentChild == null ) { return ; } if ( ! TAG_MARGIN_ADDED . equals ( mContentChild . getTag ( ) ) ) { FrameLayout . LayoutParams lp = ( FrameLayout . LayoutParams ) mContentChild . getLayoutParams ( ) ; lp . topMargin += statusBarHeight ; mContentChild . setLayoutParams ( lp ) ; mContentChild . setTag ( TAG_MARGIN_ADDED ) ; } }
target:  add marginTop to simulate set FitsSystemWindow true