Flutter：修复“参数类型”字符串＆＃x27;可以将列表分配给Dynamic＆gt;
我在扑朔迷离的项目中遇到以下错误：
The argument type 'String' can't be assigned to the parameter type
'List<dynamic>'.
代码：
import 'package:flutter/material.dart';
// ... other imports
class MainController extends StatefulWidget {
// ... existing code
}
class Functionality extends State<MainController> {
String _userName; // Likely source of the problem
int userPoints = 0;
Authenticate authenticate;
// .. existing code
Widget sideMenu(String titleName, IconData takeIcon) {
// ... existing code
if (titleName == "Account") {
List? takeInformation = authenticate.fetchDataToPreview(this._userName);
Navigator.push(
context,
MaterialPageRoute(
builder: (context) =>
AccountInformation(this._userName, takeInformation!))); // Potential null issue
}
// ... rest of the function
}
// ... rest of the code
}
我尝试过的事情：
我尝试了
最终字符串_username，但没有运气，在此行中：字符串_username;添加了“！”
takeInformation在navigator.push行中，但是错误持续accountInformation（this._username，takeInformation！）））;
问题：
- 我如何确保
authenticate.fetchdatatatopreview（） /code>确实返回list＆lt; dynamic＆gt;？是否有类型的不匹配导致此错误？ - 我如何处理
takeInformation列表中的潜在零值是否存在问题？
其他上下文
- 我正在使用Android Studio的颤动。
I'm encountering the following error in my Flutter project:
The argument type 'String' can't be assigned to the parameter type
'List<dynamic>'.
This error appears within this code:
import 'package:flutter/material.dart';
// ... other imports
class MainController extends StatefulWidget {
// ... existing code
}
class Functionality extends State<MainController> {
String _userName; // Likely source of the problem
int userPoints = 0;
Authenticate authenticate;
// .. existing code
Widget sideMenu(String titleName, IconData takeIcon) {
// ... existing code
if (titleName == "Account") {
List? takeInformation = authenticate.fetchDataToPreview(this._userName);
Navigator.push(
context,
MaterialPageRoute(
builder: (context) =>
AccountInformation(this._userName, takeInformation!))); // Potential null issue
}
// ... rest of the function
}
// ... rest of the code
}
Things I've tried:
I tried
final String _userNamebut no luck, in this line:String _userName;Added "!" to
takeInformationin theNavigator.pushline, but the error persistsAccountInformation(this._userName, takeInformation!)));
Questions:
- How can I ensure that
authenticate.fetchDataToPreview()indeed returns aList<dynamic>? Could there be a type mismatch causing this error? - Is there an issue with how I'm handling potential null values in the
takeInformationlist?
Additional Context
- I'm using Flutter with Android Studio.
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（2）
在
帐户信息类中，我想您将用户名定义为列表：如果要将用户名作为字符串类型
将其更改为：
in
AccountInformationclass, I guess you defined your user name as List like this:if you want to pass username as string type
change it to:
在Promodoroclock中，定义的数据类型必须列出，但是您正在传递_username，即字符串。
In PromoDoroClock the data type defined must be List but you are passing the _userName which is a string.