Set state separately for each ListView element. Flutter

Issue

Every element of my ListView is AnimatedContainer

AnimatedContainer(
height: _height,
...)

While changing _height via setState it works for every ListView element of course.

    Future<void> _changeHeight() async {
     setState(() {
      _height = 2;
    });}

How to set _height separately for each element AnimatedContainer?

Solution

instead of a _height variable of type double, use a key/value map with the keys as the list item's index and the value as its height

Map<int, double> heights = {};

To use the height:

AnimatedContainer(
   height: heights[index]!,
   //...
)

And to set the height:

Future<void> _changeHeight() async {
  setState(() {
    heights[index] = 2;
  });
}

Answered By - Roaa