android - Get Api Works 在模拟器中但在真实设备 Flutter 中不可用
问题描述
════════ Exception caught by widgets library ═══════════════════════════════════════════════════════
type 'StateError' is not a subtype of type 'String'
The relevant error-causing widget was:
FutureBuilder<List<User>> file:///C:/Users/Personal/Desktop/park_parcel/lib/Json%20Service/json_Delivery_Data.dart:31:14
════════════════════════════════════════════════════════════════════════════════════════════════════
这是我得到的异常/错误,我必须从服务器获取 Json 数据,它必须通过堆栈内的 future.builder 绑定到 listview.builder!
Stack(
children: <Widget>[
Container(
height: _height * 1,
width: _width * 1,
child: DeliveryBody(),
),
Positioned(
right: _width / 8,
bottom: _height / 5,
child: Container(
height: _height * 0.18,
margin: EdgeInsets.only(right: 20),
alignment: Alignment.bottomRight,
child: RaisedButton.icon(
shape: RoundedRectangleBorder(
borderRadius: BorderRadius.circular(30.0),
),
color: Colors.green[600],
icon: Icon(Icons.camera_alt, color: Colors.white),
label: Text(
'Scan Deliver',
style: TextStyle(
color: Colors.white,
),
),
onPressed: () {
_scanQR();
},
),
),
),
我的堆栈在这里结束,然后我从新页面获得下面的代码!
Future<List<User>> _getData() async {
var response = await http.get(Uri.encodeFull(url));
print(response.body);
if (response.statusCode == 200) {
return compute(parcelList, response.body);
} else {
throw Exception('Unable to fetch products from the REST API');
}
}
FutureOr<List<User>> parcelList(String responseBody) {
//FutureOr mean Either Future values or List values
var parsed = jsonDecode(responseBody).cast<Map<String, dynamic>>();
return parsed.map<User>((json) => User.fromJson(json)).toList();
}
class DeliveryBody extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Container(
child: FutureBuilder<List<User>>(
future: _getData(),
builder: (context, snapshot) {
if (snapshot.hasError) print(Text(snapshot.error));
return snapshot.hasData ? Parcels(item: snapshot.data) : NoParcel();
},
),
);
}
}
class Parcels extends StatelessWidget {
final List<User> item;
const Parcels({Key key, this.item}) : super(key: key);
@override
Widget build(BuildContext context) {
final _height = MediaQuery.of(context).size.height -
MediaQuery.of(context).padding.top -
kToolbarHeight;
final _width = MediaQuery.of(context).size.width;
return Builder(
builder: (context) => Container(
height: _height * 1,
width: _width * 1,
child: item != null
? ListView.builder(
itemCount: item.length,
itemBuilder: (BuildContext context, int index) {
return Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
ListTile(
tileColor: Colors.green[600],
title: Text(
item[index].id.toString(),
style: TextStyle(
fontWeight: FontWeight.w900,
color: Colors.white,
fontSize: 25.0),
),
),
ListTile(
onTap: () {
return Column(
children: <Widget>[
Container(
height: _height / 10,
width: _width * 1,
color: Colors.white,
margin: EdgeInsets.only(top: _height / 20),
child: Text(
'Parcel Details',
textAlign: TextAlign.center,
style: TextStyle(
fontSize: _height / 20,
decorationColor: Colors.black,
textBaseline: TextBaseline.alphabetic,
),
),
),
Container(
height: _height / 10,
width: _width * 1,
color: Colors.white,
margin: EdgeInsets.only(top: _height / 20),
child: Text(
item[index].id.toString(),
textAlign: TextAlign.center,
style: TextStyle(
fontSize: _height / 20,
decorationColor: Colors.black,
textBaseline: TextBaseline.alphabetic,
),
),
),
],
);
},
tileColor: Colors.white,
title: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: [
SizedBox(
height: 7.0,
),
Text(
"To: " + item[index].name,
style: TextStyle(
fontWeight: FontWeight.w800, fontSize: 30.0),
),
SizedBox(
height: 6.0,
),
Text(item[index].parcelNumber.toUpperCase(),
style: TextStyle(
fontWeight: FontWeight.w700,
fontSize: 24.0)),
SizedBox(
height: 7.0,
),
Text(item[index].address,
style: TextStyle(
fontWeight: FontWeight.w500,
fontSize: 20.2)),
SizedBox(
height: 7.0,
),
Text("Parcels Size:" + item[index].parcelSize,
style: TextStyle(
fontWeight: FontWeight.w500,
fontSize: 20.0)),
SizedBox(
height: 7.0,
),
],
),
trailing: Icon(
Icons.arrow_forward_ios,
size: 18.0,
),
),
],
);
},
)
: NoParcel(),
),
);
}
}
此代码在 Android 版本 10 以下的模拟器中运行良好,并使用 json 数据为我构建了一个 Lisview,但在实际设备和 Android 版本 10 以上的模拟器中给了我以下异常/错误。请帮助不知道问题是什么,我已经添加我的 pubspec.ymal 文件和 Android.Xml 文件中的所有插件,甚至是用户访问 Internet 的权限..!!
解决方案
推荐阅读
- apache2 - ubuntu php pdo_sqlsev install fall 但 sqlsrv 成功
- php - Laravel Chumper / Zipper 权限在提取时被拒绝
- itext - itextsharp 在多页中分割一行(在绝对位置)
- python - 删除字符串python中的空格和破折号
- php - 我正在尝试使用 PHP 和 mysql 制作点击计数器
- java - 当订阅者在 rxjava 中抛出异常时如何继续处理?
- angular - 开发和生产中快照组件名称的不同值
- c# - 数组 Mvc 控制器到 JavaScript
- mongodb - 如何根据不同情况应用/选择 getPlanCache() 和 hint()
- javascript - 如何在 async.parallel 方法中使异步代码同步 - NodeJs