Expansion tile expand and collapse

[rishabh singh]

I am taking this as a reference to expanding and collapsing of expansion tile-------https://stackoverflow.com/questions/48930372/flutter-collapsing-expansiontile-after-choosing-an-item----

https://pastebin.com/YHymUBtS Here is my code. What I want is if I one expansion tile is open and the user clicks on another one the other open expansion tiles should be closed.