CODEWITHSUNDEEP
flutter
SkyeBoniwell
SkyeBoniwell

Reputation: 7092

Update text when button is pressed

I'm learning flutter and I want to build a simple app that updates a quote of the day when a button is pressed.

So I combined the default flutter app that is created automatically and a tutorial I found on the web.

The quote is displayed when the app loads, but I'm not quite sure how to update it when the button is pressed.

I tried putting this line in the _incrementCounter function, but it throws an error:

 _saying = Quote();

A value of type 'Quote' can't be assigned to a variable of type 'String'.

Is there anyway to get the quote to update when I press the button?

Thanks!

--main

import 'dart:async';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage({Key key, this.title}) : super(key: key);

  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  int _counter = 0;
  String _saying = '';
  String url = 'https://quotes.rest/qod.json';

  void _incrementCounter() {
    setState(() {
      _counter++;
      _saying = Quote();   

    });
  }

  @override
  Widget build(BuildContext context) {

    return Scaffold(
      appBar: AppBar(
        title: Text(widget.title),
      ),
      body: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text("-- Quote of the Day --"), 
             Quote(),
            Text(
              'dYou have pushed the buttons this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  }
}

class Quote extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return FutureBuilder(
        future: _getQuote(),
        builder: (context, snapshot) {
          return snapshot.connectionState == ConnectionState.done
              ? Center(
                  child: Text(
                  snapshot.data,
                  textAlign: TextAlign.center,
                ))
              : Center(child: CircularProgressIndicator());
        });
  }
}

Future<String> _getQuote() async {
  final res = await http.get('http://quotes.rest/qod.json');
  return json.decode(res.body)['contents']['quotes'][0]['quote'];
}

Upvotes: 0

Views: 271

Answers (1)

Ramin
Ramin

Reputation: 599

You don't need _saying, change _incrementCounter like this

void _incrementCounter() {
    setState(() {
      _counter++;
    });
  }

Because you use setState, the build method will call again then it will recreate Quote thus it fetch data again. I suggest you read and try a better state management system like provider and bloc later. Hope this helps you.

Upvotes: 2

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