URL with %7B and %7D - flutter

Question

I'm learning to use APIs with Flutter and I'm trying to use the Open Weather Map to this but, my code is inserting this %7B and %7D in every variable that I use in URL.
actual URL:
https://api.openweathermap.org/data/2.5/weather?lat=%7B-15.783783783783784%7D&lon=%7B-47.93345625648786%7D&appid=%7Bf0060b47028a54500c466c7288e41d31%7D
This is what i want:
https://api.openweathermap.org/data/2.5/weather?lat=-15.783783783783784&lon=-47.93345625648786&appid=f0060b47028a54500c466c7288e41d31
What's wrong with my code ?
My code:
import 'package:flutter/material.dart';
import 'package:clima/services/location.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
const apiKey = 'f0060b47028a54500c466c7288e41d31';
class LoadingScreen extends StatefulWidget {
#override
_LoadingScreenState createState() => _LoadingScreenState();
}
class _LoadingScreenState extends State<LoadingScreen> {
double latitude;
double longitude;
void getLocation() async {
Location location = Location();
await location.getCurrentLocation();
latitude = location.latitude;
longitude = location.longitude;
getData();
}
void getData() async {
var url = Uri.https('api.openweathermap.org', '/data/2.5/weather', {
'lat': '{$latitude}',
'lon': '{$longitude}',
'appid': '{$apiKey}',
});
var response = await http.get(url);
if (response.statusCode == 200) {
String data = response.body;
var temperature = jsonDecode(data)['main']['temp'];
print(temperature);
} else {
print(response.statusCode);
print(url);
}
}
#override
void initState() {
getLocation();
super.initState();
}
#override
Widget build(BuildContext context) {
return Scaffold();
}
#override
void deactivate() {
super.deactivate();
}
}

Answer 1

In your getData() function, try removing the curly braces around the url parameters, like this:
var url = Uri.https('api.openweathermap.org', '/data/2.5/weather', {
'lat': '$latitude',
'lon': '$longitude',
'appid': '$apiKey',
});
Alternatively, you can concatenate the URL tring yourself like this.
var baseUrl = 'https://api.openweathermap.org/data/2.5/weather?';
var appid = 'f0060b47028a54500c466c7288e41d31';
var latString = '-15.783783783783784';
var lonString = '-47.93345625648786';
var urlString =
baseUrl + 'lat=$latString' + '&' + 'lon=$lonString' + '&' + 'appid=$appid';