Datasets:
Ekhlass
/
Flutter_Documentation

Dataset card Data Studio Files
xet
Community
1
text
stringlengths
1
474
3. Convert the http.Response to a custom Dart object
While it’s easy to make a network request,
working with a raw Future<http.Response>
isn’t very convenient. To make your life easier,
convert the http.Response into a Dart object.<topic_end>
<topic_start>
Create an Album class
First, create an Album class that contains
the data from the network request.
It includes a factory constructor that
creates an Album from JSON.Converting JSON with pattern matching is only one option.
For more information, see the full article on
JSON and serialization.
<code_start>class Album {
final int id;
final String title;
const Album({required this.id, required this.title});
factory Album.fromJson(Map<String, dynamic> json) {
return switch (json) {
{
'id': int id,
'title': String title,
} =>
Album(
id: id,
title: title,
),
_ => throw const FormatException('Failed to load album.'),
};
}
}<code_end>
<topic_end>
<topic_start>
Convert the http.Response to an Album
Use the following steps to update the createAlbum()
function to return a Future<Album>:
<code_start>Future<Album> createAlbum(String title) async {
final response = await http.post(
Uri.parse('https://jsonplaceholder.typicode.com/albums'),
headers: <String, String>{
'Content-Type': 'application/json; charset=UTF-8',
},
body: jsonEncode(<String, String>{
'title': title,
}),
);
if (response.statusCode == 201) {
// If the server did return a 201 CREATED response,
// then parse the JSON.
return Album.fromJson(jsonDecode(response.body) as Map<String, dynamic>);
} else {
// If the server did not return a 201 CREATED response,
// then throw an exception.
throw Exception('Failed to create album.');
}
}<code_end>
Hooray! Now you’ve got a function that sends the title to a
server to create an album.<topic_end>
<topic_start>
4. Get a title from user input
Next, create a TextField to enter a title and
a ElevatedButton to send data to server.
Also define a TextEditingController to read the
user input from a TextField.When the ElevatedButton is pressed, the _futureAlbum
is set to the value returned by createAlbum() method.
<code_start>Column(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
TextField(
controller: _controller,
decoration: const InputDecoration(hintText: 'Enter Title'),
),
ElevatedButton(
onPressed: () {
setState(() {
_futureAlbum = createAlbum(_controller.text);
});
},
child: const Text('Create Data'),
),
],
)<code_end>
On pressing the Create Data button, make the network request,
which sends the data in the TextField to the server
as a POST request.
The Future, _futureAlbum, is used in the next step.<topic_end>
<topic_start>
5. Display the response on screen
To display the data on screen, use the
FutureBuilder widget.
The FutureBuilder widget comes with Flutter and
makes it easy to work with asynchronous data sources.
You must provide two parameters:Note that snapshot.hasData only returns true when
the snapshot contains a non-null data value.
This is why the createAlbum() function should throw an exception
even in the case of a “404 Not Found” server response.
If createAlbum() returns null, then
CircularProgressIndicator displays indefinitely.
<code_start>FutureBuilder<Album>(
future: _futureAlbum,