How to pass many parameters from one page to another in flutter

Question

...
onTap: () {
 Navigator.push(
     context,
     MaterialPageRoute(
      builder: (context) => CategoryPage(
              snapshot.data[index]),
     ));
},
...

Using the above code i try to pass the service id and the service type to the category page ... class CategoryPage extends StatefulWidget { // final String serviceId; // final String service_type; final String categorydata;

  CategoryPage(data, {key, this.categorydata}) : super(key: key);

  // @override
  // CategoryPage(categorydata) {
  //   this.serviceId = categorydata.serviceId;
  //   this.service_type = categorydata.serviceId;
  // }

  _CategoryPageState createState() =>
      _CategoryPageState(categorydata.toString());
 }

 class _CategoryPageState extends State<CategoryPage> {
  String id = "";
  _CategoryPageState(String categorydata) {
    this.id = categorydata.serviceId;
  }
...

From the above code, I need to get the service id and service type and display the tile of the Category page with the service type parameter. Please help me on achieving this result

Answer 1

You have to pass the data like this using the categorydata parameter from CategoryPage constructor.

onTap: () {
 Navigator.push(
     context,
     MaterialPageRoute(
      builder: (context) => CategoryPage(
             categorydata: snapshot.data[index]),
     ));
},

Here you need to define a final variable inside your StatefulWidget class and initialize it from the constructor;

CategoryPage({key,required this.categorydata}) : super(key: key);

final Album categorydata;

_CategoryPageState createState() =>
    _CategoryPageState();
}

Then you can access it from the State class methods using widget keyword class, you don't need to pass it.

 class _CategoryPageState extends State<CategoryPage> {


   @override
  void initState() {
    super.initState();
    // access them from here

   final categorydata = widget.categorydata;
   final String serviceId = categorydata.service_id;
   final String service_type = categorydata. service_type;

  }

  @override
  Widget build(BuildContext context) {
    // access them from here
    final categorydata = widget.categorydata;
    final String serviceId = categorydata.service_id;
    final String service_type = categorydata. service_type;
   }

  }