How to darken (fade) all View except one?

Question

Android

It is necessary to dim everything except the expanded View by opening in the ExpandedListView. How to darken (fade) all View except one?

Answer 1

I would try this:
on the OnGroupExpandListener expansion event, we receive the position of the expanded group
onGroupExpand(int groupPosition). We pass GroupPosition to the adapter so that in getGroupView(int groupPosition, boolean isExpanded, View convertView, ViewGroup parent) we darken everything except the passed GroupPosition
and call invalidateViews()
And in OnGroupCollapseListener we reset everything

Answer 2

To darken the entire area, except for this view, you need to set the view style with parameters in style.xml:

<item name="android:backgroundDimEnabled">true</item>
<item name="android:windowIsFloating">true</item>