dart - 如何在带有DartFlutter的不同类上使用变量
原创dart - 如何在带有DartFlutter的不同类上使用变量
原创
我有一类是我的getToken类。在此类中，我得到的 token 是字符串 token 。这是我的 getToken.dart
class GetToken {
String token;
Future<Null> getData() async {
var url = "http://192.168.1.39:7070/api/v2/token";
http.post(url, body: {
"grant_type": "string",
"branchcode": "string",
"password": "string",
"username": "string",
"dbname": "string",
"dbuser": "string",
"dbpassword": "string",
"dbtype": "string"
}).then((response) {
print("Response Status: ${response.statusCode}");
//print("Response Body: ${response.body}");
print('access token is -> ${json.decode(response.body)['access_token']}');
token = json.decode(response.body)['access_token'];
});
}
}我想在我的getCari类中使用此 token ，并在我的rest api中获取Json值。这是我的 getCari.dart 类别
class GetCari{
getCari() async {
final response = await http.get("http://192.168.1.39:7070/api/v2/ARPs",
headers: {HttpHeaders.AUTHORIZATION: token});
if(response.statusCode ==200){
return Cari.fromJson(json.decode(response.body));
}else{
throw Exception("Failed to Load");
}
}
}我想问一下如何在我的getCari.dart类中使用我的 token (从getToken.dart获取)。我如何将 token 变量传递给其他类？
最佳答案
请使用Dart的顶级函数而不是不需要实例化的类。
这在Effective Dart documentation中提到
token_manager.dart
String _token;
String get token => _token // To ensure readonly
Future<Null> setToken() async {
// set your _token here
}get_cari.dart
import 'token_manager.dart' as token_manager // use your import path here
getCari() async {
// You can now access token from token_manager from any class like this.
final String token = token_manager.token;
}摘抄
In Java and C#, every definition must be inside a class, so it’s common to see “classes” that exist only as a place to stuff static members. Other classes are used as namespaces—a way to give a shared prefix to a bunch of members to relate them to each other or avoid a name collision. Dart has top-level functions, variables, and constants, so you don’t need a class just to define something. If what you want is a namespace, a library is a better fit. Libraries support import prefixes and show/hide combinators. Those are powerful tools that let the consumer of your code handle name collisions in the way that works best for them. If a function or variable isn’t logically tied to a class, put it at the top level. If you’re worried about name collisions, give it a more precise name or move it to a separate library that can be imported with a prefix.
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原创声明：本文系作者授权腾讯云开发者社区发表，未经许可，不得转载。
如有侵权，请联系 cloudcommunity@tencent.com 删除。