Flutter : How can I get Value of a varibale from a Async method and pass it to Text Widget?-CodePudding

I want to show the user some weather data [temperature, condition, cityName]. I am getting the weather data(jsonDecoded) using an Asynchronous method. But I am unable to pass that data to the Text widget. I have tried this Way, but the Text widget shows Null in the emulator.

Here is my Code-

class _MyHomePageState extends State<MyHomePage> {

///want to pass this data to text Widget
var temperature;
var condition;
var cityName;

 initState() {
 LocationData();
}

var Longtitude;
var Latitude;

// By this method I am getting weatherData from another class
LocationData() async {
getlocation GetLocation = getlocation();
await GetLocation.determinePosition();

Latitude = GetLocation.Lattitude;
Longtitude = GetLocation.Longtitude;

NetworkHelper networkHelper = NetworkHelper(
    'https://api.openweathermap.org/data/2.5/weather? 
     lat=$Latitude&lon=$Longtitude&appid=$apiKey');

var weatherData = await networkHelper.getData();

temprature = weatherData['main']['temp'];
condition = weatherData['weather'][0]['id'];
cityName = weatherData['name'];

}

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Container(
        child: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: [
                Text(
                temprature.toString(),
                style: MyTextStyle,
                            ),
                Text(
                condition.toString(),
                style: MyTextStyle,
                            ),
                Text(
                cityName.toString(),
                style: MyTextStyle,
                            )
             ],
           ),
         ),
       ),
     );

     // TODO: implement build
     throw UnimplementedError();
  }
 }

CodePudding user response：

Try doing this after you've fetched the weatherData:

setState(() {
  temprature = weatherData['main']['temp'];
  condition = weatherData['weather'][0]['id'];
  cityName = weatherData['name'];
});

There are more things you will run into that won't be top-notch... I suggest that you e.g. checkout the FutureBuilder() widget and see how that could be used in your case.

CodePudding user response：

If in LocationData method if you're getting the correct value in temperature, condition and cityname then issue with you're not using setState there. As widget will not re-render until setState is used and thus variable displays old values there for temperature/condition.

Use setState in LocationData.

setState(() {
  temprature = weatherData['main']['temp'];
  condition = weatherData['weather'][0]['id'];
  cityName = weatherData['name'];
});