Question

在这里，我正在尝试从Firestore获取地点名称。我做了一个getplaces函数，该函数从firestone导入文件并将它们放在列表中。为了在标签栏上显示位置。

问题是：即使Iam在您的init状态下调用该函数，它也会返回“带有列表的温度” 的错误超出了范围0的范围，即使当我打印温度列表时它也会正确打印位置。

import 'package:flutter/material.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'dart:async';




 class HomePage extends StatefulWidget {
 // const HomePage({Key key}) : super(key: key);

  @override
  HomePageState createState() {
    return new HomePageState();
  }
}

class HomePageState extends State<HomePage> {
List<String> temp=new List();
List<String> temp1=['Nile University', 'Smart Village', 'Zewail'];
@override
void initState() {
    super.initState();

  getplaces(temp);
  }

Future<List> getplaces(temp) async{
 QuerySnapshot place= await  Firestore.instance.collection('places').getDocuments();
  place.documents.forEach((DocumentSnapshot doc){
    temp.add(
      doc.data['name']
    );
             print(doc.data['name']);

  });
   print(temp);
  return temp;
  }



  @override
  Widget build(BuildContext context) {
   return  DefaultTabController(
      length: 20,
      child: Scaffold(
      appBar: AppBar(
         title: Text("Home Page"),
         bottom:  TabBar( isScrollable: true,
              tabs: new List.generate(temp.length, (index) {
                     return new Tab(child: Text(temp[index].toString().toUpperCase()));
              }),),),

  body: !temp.isNotEmpty?
         Center(child: CircularProgressIndicator()):

         TabBarView(
          children: <Widget>[
            Text(temp[0].toString()),
            Icon(Icons.directions_transit),
            Icon(Icons.directions_bike),
          ],
        ))); 
  }}




                      //String f=snapshot.data.documents[index]["Place"].toString();




                               // print( Firestore.instance.collection("Places").document(f).collection("order 1").document('order 1').snapshots().toString());






        //    return TabBar(
      //      isScrollable:true,
      //    tabs: ListView.builder(
      //     itemCount: snapshot.data.documents.length,
      //     itemBuilder: (context,int index)=>
      //      Tab(text: snapshot.data.documents[index]["Place"].toString().toUpperCase())
      // )) ;     
//           return ListView.builder(
//           itemCount: snapshot.data.documents.length,
//           itemBuilder: (context,int index)=>
//           FlatButton(


//             child: Row(
//               children: <Widget>[


//                Flexible(child: Text(snapshot.data.collections[index].toString())),


//               ],
//             ),
//             onPressed:null,

// padding: EdgeInsets.fromLTRB(25.0, 10.0, 25.0, 10.0),
//           shape: RoundedRectangleBorder(borderRadius: BorderRadius.circular(10.0)),
//           ),
//         );


 // String s=snapshot.data.documents[0]["Place"].toString();
        // print("place is $s"

颤振列表-从消防处-超出范围错误？

0 个答案: