而是将格式错误的类型参数替换为dynamic,这是运行时使用的类型参数。 List<UndefinedType> l = <int>[3]; // warning, but works even in checked model List<int> list = <UndefinedType>[3]; // warning, but works even in checked mode 这里,l的类型被认为为List <dynamic>。发出一个警告,表明未...
第一种方法是在流的initialData中添加一个流类型的数据。第二个是在您的snapShot.data包含null值。检查...
// a 'dynamic' variable can be assigned value of any type dynamic a = 2; // assign 'dynamic' value to any variable and code checker will not complain int b = a; // even when there is a bug String c = a; 案例2(对象) // It is OK to assign a 'int' value to an 'Object...
ReceivePort _receivePort = ReceivePort(); void _handleNativeMessage(dynamic message) { print('_handleNativeMessage $message'); final int address = message; nativeLibrary.executeCallback(Pointer<Void>.fromAddress(address).cast()); /// 如果执行完成,需要将其close,不一定是放到这里 _receivePort.close...
当我试图将json转换成一个对象时,出现了这个错误: Unhandled Exception: type '_InternalLinkedHashMap<dynamic, dynamic>' is not a subtype of type 'Map<String, dynamic>' 只有当我尝试将object类型...
抛出此错误是因为Page已在package:flutter/src/widgets/navigator.dart中定义。您可以添加前缀以唯一定义...
类型“ List<dynamic>”不是类型的子类型“ List<ExchangeRate>” 如您在代码中所见,我在其中创建并返回了新的ExchangeRate对象.map(),然后返回了rateEntries.toList()我希望是type的a List<ExchangeRate>,但是似乎可以推断为type List<dynamic>!@override Future<List<ExchangeRate>> getExchangeRatesAt(DateTime ...
Applying type inference on List<String> a; [ for (final {'event': String event} in a.map(jsonDecode)) switch(event) ... ]; gives an error where the type dynamic can't be inferred for the .map call. Changing the call to .map<dynamic> mak...
Dart Unhandled Exception: type 'List<dynamic>' is not a subtype of type 'Iterable<Map<dynamic, dynamic>>' in type cast, stack trace: #0 UserModel._convertCartItems (package:test_app/model/user.dart:67:31) E/flutter (30545): #1 new UserModel.fromSnapshot (package:test_app/model/user....
type 'List<dynamic>' is not a subtype of type 'List<int>' in type cast こうしたときは、.cast<int>()でint型へキャストすることで、エラーを回避できます。 finalallSentences=widget.assets['sentences'];finalthisSentence=allSentences[widget.sentenceNo-1]asMap<String,dynamic>;// .cast<in...