如何在flutter中将API模型对象存储在本地存储中

Question

我在代码中使用本地存储(shared_preferences:^2.0.6(时发现了这个问题。。。。但是我无法将api模型对象存储在本地存储中。。。我该怎么办？

storeModelInPrefs() async {
http.Response response =
await http.get(Uri.parse('http://18.191.193.64/api/view_categories'));

String encodeData = jsonEncode(response.body);
///Write Data in local Storage 
GetStorageUtility.prefs!.write('key', encodeData);
///Read Data from local Storage 
String data = GetStorageUtility.prefs!.read('key');
if (data == null) {
print('no data in GetStorage');
} else {
Map<String, dynamic> map = jsonDecode(data);
print(map);
}
}

Answer 1

这是我根据您提供的代码创建的示例。

import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:flutter_app/utilities.dart';
import 'package:http/http.dart' as http;
void main() {
runApp(MaterialApp(
home: MyApp(),
));
}
class MyApp extends StatefulWidget {
@override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
@override
void initState() {
GetStorageUtility.init();
super.initState();
getRemoteData();
}
getRemoteData() async {
/// This is where the api is fetching the data
var response =
await http.get(Uri.parse('http://18.191.193.64/api/view_categories'));
/// This is where the string getting
String encodeData = jsonEncode(response.body);
GetStorageUtility.write("key", encodeData);
/// this is where you fetch the data
String data = GetStorageUtility.read("key");
if (data == null) {
print('no data in GetStorage');
} else {
Map<String, dynamic> jsonData = json.decode(data);
jsonData.forEach((key, value) {
print("$key :  $valuen");
});
}
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: Center(
child: Text(" Page"),
),
);
}
}

SharadPrefs Singleton，

import 'dart:async';
import 'package:shared_preferences/shared_preferences.dart';
class GetStorageUtility {
static Future<SharedPreferences> get _instance async =>
_prefsInstance ??= await SharedPreferences.getInstance();
static SharedPreferences _prefsInstance;
static Future<SharedPreferences> init() async {
_prefsInstance = await _instance;
return _prefsInstance;
}
static String read(String key, [String defValue]) {
return _prefsInstance.getString(key) ?? defValue ?? "";
}
static Future<bool> write(String key, String value) async {
var prefs = await _instance;
return prefs?.setString(key, value) ?? Future.value(false);
}
}

现在有一件事，你已经看到，你已经添加到你的android清单文件

<application android:usesCleartextTraffic="true" />

这个应该在那里，互联网权限应该在调试和主文件夹manifestfile中。

这是可行的，但这不是将数据作为字符串存储在共享数据引用中的最佳做法。Shared Prefs只负责管理像bool或string这样的小数据。对于您的用例，您可以使用sqlite作为本地数据库。在那里您可以根据条件获取数据。

如果有效，请告诉我。

快乐编码。