参考的2段代码 https://flutter.dev/docs/cookbook/networking/background-parsing
First, create a Photo
class that contains data about a photo. Include a fromJson()
factory method to make it easy to create a Photo
starting with a JSON object.
class Photo {
final int id; final String title; final String thumbnailUrl; Photo({this.id, this.title, this.thumbnailUrl}); factory Photo.fromJson(Map<String, dynamic> json) { return Photo( id: json['id'] as int, title: json['title'] as String, thumbnailUrl: json['thumbnailUrl'] as String, ); } }
Convert the response into a list of photos
Now, use the following instructions to update the fetchPhotos()
function so that it returns a Future<List<Photo>>
:
- Create a
parsePhotos()
function that converts the response body into aList<Photo>
. - Use the
parsePhotos()
function in thefetchPhotos()
function.
// A function that converts a response body into a List<Photo>.
List<Photo> parsePhotos(String responseBody) { final parsed = json.decode(responseBody).cast<Map<String, dynamic>>(); return parsed.map<Photo>((json) => Photo.fromJson(json)).toList(); } Future<List<Photo>> fetchPhotos(http.Client client) async { final response = await client.get('https://jsonplaceholder.typicode.com/photos'); return parsePhotos(response.body); }