Android 10.0 SystemUI Modify the spacing of each notification in the drop-down notification bar

In the native SystemUI, the distance between each notification in the pull-down status bar is separated by a horizontal line, which is not very beautiful, so it is necessary to make customized changes. The
first choice is to see the source code NotificationChildrenContainer.java

路径为：frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/NotificationChildrenContainer.java

  /**
     * Add a child notification to this view.
     *
     * @param row the row to add
     * @param childIndex the index to add it at, if -1 it will be added at the end
     */
    public void addNotification(ExpandableNotificationRow row, int childIndex) {
   
    
    
        int newIndex = childIndex < 0 ? mChildren.size