API密钥不工作在扑动天气API应用程序(Android)

Question

我正在学习Flutter并试图构建一个Android应用程序。基本上是一个天气应用程序，它从一个站点获取API密钥。总是出现错误"参数类型'String'不能分配给参数类型'Uri'。"。这到底是什么意思，我怎么让它工作?

main.dart

import 'package:flutter/material.dart';
import 'package:font_awesome_flutter/font_awesome_flutter.dart';
import 'package:http/http.dart' as http;
import 'dart:convert';
void main() => runApp(
MaterialApp(
title: "Weather App",
home: Home(),
)
);
class Home extends StatefulWidget {
@override
State<StatefulWidget> createState(){
return _HomeState();
}
}
class _HomeState extends State<Home> {
var temp;
var description;
var currently;
var humidity;
var windSpeed;
Future getWeather () async {
http.Response response = await http.get("http://api.weatherapi.com/v1/current.json?key=e5bd00e528e346ff8a840254213009&q=Chatham Ontario&aqi=no");
var results = jsonDecode(response.body);
setState((){
this.temp = results['current']['temp_c'];
this.description = results['current'][0]['last_updated'];
this.currently = results['current'][0]['condition']['text'];
this.humidity = results['current']['humidity'];
this.windSpeed = results['current']['wind_kph'];
});
}
@override
void initState() {
super.initState();
this.getWeather();
}
@override
Widget build (BuildContext context) {
return Scaffold(
body: Column(
children: <Widget>[
Container(
height: MediaQuery.of(context).size.height / 3,
width: MediaQuery.of(context).size.width,
color: Colors.red,
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
crossAxisAlignment: CrossAxisAlignment.center,
children: <Widget>[
Padding(
padding:EdgeInsets.only(bottom: 10.0),
child: Text(
"Currently in Chatham-Kent",
style: TextStyle(
color: Colors.white,
fontSize: 14.0,
fontWeight: FontWeight.w600
),
),
),
Text(
temp != null ? temp.toString() + "u00B0" : "Loading",
style: TextStyle(
color: Colors.white,
fontSize: 40.0,
fontWeight: FontWeight.w600
),
),
Padding(
padding:EdgeInsets.only(top: 10.0),
child: Text(
currently != null ? currently.toString() : "Loading",
style: TextStyle(
color: Colors.white,
fontSize: 14.0,
fontWeight: FontWeight.w600
),
),
),
],
),
),
Expanded(
child: Padding(
padding: EdgeInsets.all(20.0),
child: ListView(
children: <Widget>[
ListTile(
leading: FaIcon(FontAwesomeIcons.thermometerHalf),
title: Text("Temperature"),
trailing: Text(temp != null ? temp.toString() + "u00B0" : "Loading"),
),
ListTile(
leading: FaIcon(FontAwesomeIcons.cloud),
title: Text("Weather"),
trailing: Text(description != null ? description.toString() : "Loading"),
),
ListTile(
leading: FaIcon(FontAwesomeIcons.sun),
title: Text("Humidity"),
trailing: Text(humidity != null ? humidity.toString() : "Loading"),
),
ListTile(
leading: FaIcon(FontAwesomeIcons.wind),
title: Text("Wind Speed"),
trailing: Text(windSpeed != null ? windSpeed.toString() : "Loading"),
)
],
)
)
)
],
),
);
}
}

pubspec.yaml

version: 1.0.0+1
environment:
sdk: '>=2.10.0 <3.0.0'
dependencies:
flutter:
sdk: flutter
cupertino_icons: ^1.0.2
font_awesome_flutter: ^8.0.0
http: ^0.13.3
dev_dependencies:
flutter_test:
sdk: flutter
flutter_lints: ^1.0.0
flutter:
uses-material-design: true

Answer 1

你的错误显然是The argument type 'String' can't be assigned to the parameter type 'Uri'，所以你必须将url字符串转换为Uri。

:

var uri = Uri.parse("http://api.weatherapi.com/v1/current.json?key=e5bd00e528e346ff8a840254213009&q=Chatham Ontario&aqi=no");
http.Response response = await http.get(uri);

Answer 2

修改这行代码

http.Response response = await http.get("http://api.weatherapi.com/v1/current.json?key=e5bd00e528e346ff8a840254213009&q=Chatham Ontario&aqi=no");

http.Response response = await http.get(Uri.parse("http://api.weatherapi.com/v1/current.json?key=e5bd00e528e346ff8a840254213009&q=Chatham Ontario&aqi=no"));

Answer 3

基于HTTP包文档。

0.13.0-nullsafety。0版本所有以前允许传递字符串或Uri的api现在都需要一个Uri。因此，这里发生的事情是，您需要在调用之前首先解析(转换)您的字符串为uri。

那么你的天气函数将是这样的:

Future getWeather () async {
http.Response response = await http.get(Uri.parse("http://api.weatherapi.com/v1/current.json?key=e5bd00e528e346ff8a840254213009&q=Chatham Ontario&aqi=no"));
var results = jsonDecode(response.body);
setState((){
this.temp = results['current']['temp_c'];
this.description = results['current'][0]['last_updated'];
this.currently = results['current'][0]['condition']['text'];
this.humidity = results['current']['humidity'];
this.windSpeed = results['current']['wind_kph'];
});
}