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flutter - Flutter 共享首选项——未处理的异常：空值检查运算符用于空值

问题描述

共享偏好插件 (shared_preferences: ^2.0.6)

它有一个初始化实例错误，这是错误堆栈跟踪：

aunching lib/main.dart on iPhone 12 Pro Max in debug mode...
package:travel_app/main.dart:1
Xcode build done.                                           22.3s
Connecting to VM Service at ws://127.0.0.1:59168/kc8UwLPVK5s=/ws
flutter: start
[VERBOSE-2:ui_dart_state.cc(199)] Unhandled Exception: Null check operator used on a null value
#0      MethodChannel.binaryMessenger
package:flutter/…/services/platform_channel.dart:142
#1      MethodChannel._invokeMethod
package:flutter/…/services/platform_channel.dart:148
#2      MethodChannel.invokeMethod
package:flutter/…/services/platform_channel.dart:331
#3      MethodChannel.invokeMapMethod
package:flutter/…/services/platform_channel.dart:358
#4      MethodChannelSharedPreferencesStore.getAll
package:shared_preferences_platform_interface/method_channel_shared_preferences.dart:44
#5      SharedPreferences._getSharedPreferencesMap
package:shared_preferences/shared_preferences.dart:180
#6      SharedPreferences.getInstance
package:shared_preferences/shared_preferences.dart:56
#7      Global.init
package:travel_app/common/Global.dart:36
#8      main
package:travel_app/main.dart:13
#9      _runMainZoned.<anonymous closure>.<anonymous closure> (d<…&gt;

这是我的代码（main.dart）：

Future<void> main() async => await Global.init().then((e) => runApp(MyApp()));

全球飞镖

static Future init() async {
print("start");
final SharedPreferences prefs = await 
SharedPreferences.getInstance();
print("_prefs $prefs");
}

源代码定位器错误是这些：（method_channel_shared_preferences.dart）

await _kChannel.invokeMapMethod<String, Object>('getAll');

发生异常。_CastError（用于空值的空检查运算符）

否则，我使用的系统是MacOS，有人知道如何解决这个问题吗？

标签： flutterdart

解决方案

WidgetsFlutterBinding.ensureInitialized();初始化前做

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