小编Sid*_*rth的帖子

import 'package:flutter/material.dart';\nimport 'package:dropdownfield/dropdownfield.dart';\nimport 'package:http/http.dart' as http;\n\nclass Formwidget extends StatefulWidget {\n\n  @override\n  _FormwidgetState createState() => _FormwidgetState();\n}\n\nclass _FormwidgetState extends State<Formwidget> {\n\n\n  Map locationDataBangalore;\n  fetchlocationData()async{\n    http.Response locationData = await http.get("http://192.168.0.102:5000/get_location_names");\n    setState(() {\n      locationDataBangalore = jsonDecode(locationData.body);\n    });\n    print(locationDataBangalore['locations']);\n  }\n  @override\n  void initState() {\n    fetchlocationData();\n    super.initState();\n  }\n\n  @override\n  Widget build(BuildContext context) {\n    return locationDataBangalore == null ? Center(child: CircularProgressIndicator(),) :Container(\n      child: Column(\n        children: <Widget>[\n          DropDownField(\n            controller: locationController,\n            hintText: "Select Location",\n            enabled: true,\n            items: locationDataBangalore["locations"],\n          ),\n        ],\n      ),\n    );\n  }\n}\n\nfinal locationController = TextEditingController();\n

来自 API“http://192.168.0.102:5000/get_location_names”的 …

GetPhotoUrlStream 提供存储在我的 Cloud Firebase FireStore 中的个人资料照片 (data['profilePhoto']) 的 Url 流。然后被网络图像用来显示个人资料照片（圆形头像）

 class GetUserPhotoUrlStream extends StatelessWidget {
      final String documentId; // This is your User UID
    
      GetUserPhotoUrlStream(this.documentId);
    
      @override
      Widget build(BuildContext context) {
        DocumentReference users = FirebaseFirestore.instance.collection('users').doc(documentId);
        return StreamBuilder<DocumentSnapshot>(
          stream: users.snapshots(),
          builder:  (BuildContext context, AsyncSnapshot<DocumentSnapshot> snapshot) {
    
            if (snapshot.hasError) {
              return Image.asset('assets/images/NouserImage.png');
            }
    
            if (snapshot.connectionState == ConnectionState.waiting) {
              return CircularProgressIndicator();
            }
    
            Map<String, dynamic> data = snapshot.data.data();
            return  CircleAvatar(
                maxRadius: 80,
                backgroundColor: Colors.grey,
                child: ClipOval(child: FadeInImage(placeholder: AssetImage('assets/images/NouserImage.png'),image: NetworkImage("${data['profilePhoto']}"),),),
               
            );
          },
        );
      }
    }

removeUserPhotoUrl …