title: Is there a way in Flutter to allow only one ExpansionTile of a dynamic generated ListView to be expanded?
body: <p>Is there a way in Flutter to allow only one ExpansionTile of a dynamic generated ListView to be expanded?</p>
  
  <p>E.g. my ListView has three ExpansionTiles and I click on the first one, it expands. Now, if I tap on the second one, the second one should expand whereas the first one should close itself.</p>
  
  <p>In my head it should work like putting this task into the "onExpansionChanged" method but I don't know how.</p>