How to clear list when navigate back or when function is finished in flutter?-CodePudding

I have a list of ingredients that I want to clear when user go back and redo the same function. How can I achieve that? Until now, when user redo the operations, old results still show on Result page.

This is my main page button:

ElevatedButton(onPressed: (){
            if (index == 1){
              multiply();
              Navigator.of(context).pop();
              Navigator.of(context).push(
                  MaterialPageRoute(builder: (context) => result(newList)));

            }else {
              divide();
              Navigator.of(context).pop();
              Navigator.of(context).push(
                  MaterialPageRoute(builder: (context) => result(newList)));
            };
          }, child: Text('Calculate'.toUpperCase(),style: TextStyle(fontWeight: FontWeight.bold),),
            style: ElevatedButton.styleFrom(
                primary: Colors.green),
          ),],

and this is the Result page with a list to clear:

@override
Widget build(BuildContext context) {
return Scaffold(
  appBar: AppBar(
    backgroundColor: Colors.deepOrange,
    title: Text('Result'),
    centerTitle: true,
  ),
  body:  Padding(
    padding: const EdgeInsets.only(top: 15.0),
    child: ListView.builder(itemBuilder: (contetx ,index) {
      return Column(
        children:[
        Padding(
          padding: const EdgeInsets.only(top: 8.0, left: 15, right: 15),
          child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            Container(child: Text(widget.newList[index].name,
              style: TextStyle(fontWeight: FontWeight.bold),),
              margin: EdgeInsets.only(left: 5.0),),
            Container(child: Text(widget.newList[index].quantity,
              style: TextStyle(fontSize: 18),)),
          ],
          ),
        ),
          Divider(thickness: 1,indent: 20,endIndent: 20,),
        ],
      );
    },
      itemCount: widget.newList.length,

    ),
  ),
);
}
}

CodePudding user response：

You can achieve that by multiple ways, 1- The following way, creates a new list to be passed, and immediately clears the original list

Navigator.of(context).push(
              MaterialPageRoute(builder: (context) => result([...newList])));
newList.clear();

2- wait until Result screen is popped

ElevatedButton(onPressed: () async {
    ....
    await Navigator.of(context).push(
              MaterialPageRoute(builder: (context) => result(newList)));
    newList.clear();