Flutter Common Errors
1 The argument type ‘String’ can’t be assigned to the parameter type ‘Uri’.
| Old Code | Replace With |
| http.get(String) | http.get(Uri.parse(String)) |
| http.post(String) | http.post(Uri.parse(String)) |
In your specific example, you will need to use Like This :-
await http.post(
Uri.parse("https://api.instagram.com/oauth/access_token"),
body: {
"client_id": clientID,
"redirect_uri": redirectUri,
"client_secret": appSecret,
"code": authorizationCode,
"grant_type": "authorization_code",
});
2. The operator ‘[]’ isn’t defined for the type ‘Object’.
ModalRoute.settings.arguments is a property with the type Object.so you can make it Map
Widget build(BuildContext context) {
var rcvdData = ModalRoute.of(context)!.settings.arguments as Map;
print(rcvdData['name']);
print("rcvd data is : ${rcvdData}");
3 . String Convert Into Double
String numInString = '3467.19';
double num1= double.parse('${numInString}');
4. A value of type ‘Object?’ can’t be assigned to a variable of type ‘Map <dynamic,dynamic>’.
create a class for define the argument. what you have needed.
class ProductDetailsArguments {
final Product product;
ProductDetailsArguments({required this.product});
}
Now extracts the arguments Like This :-
Widget build(BuildContext context) {
final args = ModalRoute.of(context)!.settings.arguments as ProductDetailsArguments;
Full Code
You can Send Argument like This
onTap: (){
Navigator.pushNamed(
context,
DetailsScreen.routeName,
arguments: ProductDetailsArguments(product: product),
);
},
Now get extracts arguments
import 'package:flutter/material.dart';
import '../../models/Products.dart';
import 'components/body.dart';
import 'components/custom_app_bar.dart';
class DetailsScreen extends StatelessWidget {
static String routeName = "/details";
// late Map product;
@override
Widget build(BuildContext context) {
final args = ModalRoute
.of(context)!
.settings
.arguments as ProductDetailsArguments;
return Scaffold(
backgroundColor: Color(0xFFF5F6F9),
// appBar:AppBar(title: Text("hii"),),
appBar: PreferredSize(
preferredSize:Size.fromHeight(AppBar().preferredSize.height),
child: CustomAppBar()
),
body: Body(product: args.product, key: ValueKey("singleProduct"),),
// body:Container(),
);
}
}
class ProductDetailsArguments {
final Product product;
ProductDetailsArguments({required this.product});
}
5 . Vertical viewport was given unbounded height.
Viewports expand in the scrolling direction to fill their container. In this case, a vertical viewport was given an unlimited amount of vertical space in which to expand. This situation typically happens when a scrollable widget is nested inside another scrollable widget.
If this widget is always nested in a scrollable widget there is no need to use a viewport because there will always be enough vertical space for the children. In this case, consider using a Column instead. Otherwise, consider using the “shrinkWrap” property (or a ShrinkWrappingViewport) to size the height of the viewport to the sum of the heights of its children.
There are 4 way to solve this error:-
- Adding this two line in your ListView.builder
ListView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
...
if your are using GridView.builder then you can you like this-
GridView.builder(
scrollDirection: Axis.vertical,
shrinkWrap: true,
...
- Wrap
ListViewinExpanded
Column(
children: <Widget>[
Expanded( // wrap in Expanded
child: ListView(...),
),
],
)
- Use
shrinkWrap: trueinListView.
Column(
children: <Widget>[
ListView(
shrinkWrap: true, // use this
),
],
)
- Wrap
ListViewinSizedBoxand give a boundedheight
Column(
children: <Widget>[
SizedBox(
height: 400, // fixed height
child: ListView(...),
),
],
)