如何在flutter中的listview.builder中的索引处设置小部件的状态

Question

I have this listview.builder in a stream builder. Inside the listview I have a button and circular progress indicator in a container at every index, now I want to show the circular indicator at that particular index only when the button is pressed.

I have tried to use a boolean to hide and show the indicator. however my problem is when every try to make the indicator visible all of them become visible which is not what I want. how can I achieve this?

Answer 1

This is an Example to demonstrate How to use a widget which manages its own state in a listview builder.

class MainClass extends StatefulWidget {
  @override
  _MainClassState createState() => _MainClassState();
}

class _MainClassState extends State<MainClass> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),
      body: Column(
        children: <Widget>[
          ListView.builder(
           // itemCount: ,
            itemBuilder: (context,index){
                return HoldNewStateOf(
                  descriptions: "Description From List",
                  index: index,
                  name: "Name From List",
                );
            },
          )
        ],
      ),
    );
  }
}



class HoldNewStateOf extends StatefulWidget {
final name;
final descriptions;
final index;

HoldNewStateOf({
this.name,
this.descriptions,
this.index,
});
  @override
  _HoldNewStateOfState createState() => _HoldNewStateOfState();
}

class _HoldNewStateOfState extends State<HoldNewStateOf> {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Column(
        children: <Widget>[
          Text("Name: ${widget.name}"),
           Text("Description: ${widget.descriptions}"),
            Text("Current Index: ${widget.index}"),
        ],
      ),
    );
  }
}

Answer 2

您应该将每个列表项构建为具有自己的逻辑和状态的单独小部件，这样您就可以为每个项目拥有不同的布尔状态属性。