How can I update a Network Image in Flutter - http

Question

I'm currently learning Flutter and I wanted to try out Network Requests and working with Futures.
I want to show a random image from unsplash.com using their API and I want to change the image every time I press a certain button.
I tried implementing a function to change the image, but it doesn't work.
My code looks like this:
import 'package:flutter/material.dart';
import 'package:http/http.dart' as http;
import 'dart:async';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: RandomImage(),
);
}
}
class RandomImage extends StatefulWidget {
#override
_RandomImageState createState() => _RandomImageState();
}
class _RandomImageState extends State<RandomImage> {
static String imageUrl = 'https://source.unsplash.com/random/300x200';
Future _imgFuture = http.get(imageUrl);
void _changeImage() async {
_imgFuture = http.put(imageUrl);
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: (Text('Hello')),
),
body: Center(
child: Column(
children: [
Spacer(),
FutureBuilder(
future: _imgFuture,
builder: (context, snapshot) {
if (snapshot.hasError) {
return Text('Oops, there was an error');
} else if (snapshot.hasData) {
return Image.network(imageUrl);
} else {
return Text('No value yet');
}
},
),
RaisedButton(
child: Text('Change Image!'),
onPressed: () => setState(() {
_changeImage();
}),
),
Spacer(),
],
),
),
);
}
}

Answer 1

Actually, Image.network is keeping your image, for more detail to see It here. The solution for this issue is make a simple useless query to api, so the image will be identical differently in flutter.
RaisedButton(
child: Text('Change Image!'),
onPressed: () => setState(() {
// _changeImage();
imageUrl="https://source.unsplash.com/random/300x200?v=${DateTime.now().millisecondsSinceEpoch}";
}),
),
The image won't change If you call the api too frequently, you might want to add a timer to prevent user from clicking too often.

Answer 2

I think the problem is in the _changeImage() method, try replace http.put with http.get.