如何使用颤振从firebase实时检索数据

Posted 2023-02-23

【中文标题】如何使用颤振从firebase实时检索数据

【英文标题】：How to retrieve data from firebase realtime with flutter

【发布时间】：2020-09-10 11:29:17

【问题描述】：

我在下面有一个屏幕

当我点击配置文件按钮时，我想从我的 firebase 实时数据库中检索当前配置文件的所有数据并显示在下一页（下图）上。

这些是我想在上面的页面上显示的数据。

这是我的编辑配置文件屏幕设计代码。

Widget _NameTextField(String _name) 
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[
        Text(
          'Full Name',
          style: kLabelStyle,
        ),
        SizedBox(height: 10.0),
        Container(
          alignment: Alignment.centerLeft,
          decoration: kBoxDecorationStyle,
          height: 60.0,
          child: TextFormField(
            autovalidate: false,
            style: TextStyle(
              color: Colors.white,
              fontFamily: 'OpenSans',
            ),
            decoration: InputDecoration(
              border: InputBorder.none,
              contentPadding: EdgeInsets.only(top: 14.0),
              prefixIcon: Icon(
                Icons.perm_identity,
                color: Colors.white,
              ),
              hintText: 'Enter your Full Name',
              hintStyle: kHintTextStyle,
            ),
            initialValue: _name,
            validator: (String value) 
              if (value.isEmpty) 
                return 'Name is Required.';
              
              if (value.length < 3) 
                return 'Name must be more than 2 charater';
              
              return null;
            ,
            onSaved: (String value) 
              return _name = value;
            ,
          ),
        ),
      ],
    );
  

  Widget _NICTextField() 
    return Column(
      crossAxisAlignment: CrossAxisAlignment.start,
      children: <Widget>[
        Text(
          'NIC No:',
          style: kLabelStyle,
        ),
        SizedBox(height: 10.0),
        Container(
          alignment: Alignment.centerLeft,
          decoration: kBoxDecorationStyle,
          height: 60.0,
          child: TextFormField(
            keyboardType: TextInputType.text,
            autovalidate: false,
            style: TextStyle(
              color: Colors.white,
              fontFamily: 'OpenSans',
            ),
            decoration: InputDecoration(
              border: InputBorder.none,
              contentPadding: EdgeInsets.only(top: 14.0),
              prefixIcon: Icon(
                Icons.assignment_ind,
                color: Colors.white,
              ),
              hintText: 'Enter your NIC Number',
              hintStyle: kHintTextStyle,
            ),
            validator: (String value) 
              if (value.isEmpty) 
                return 'NIC is Required.';
              
              return null;
            ,
            onSaved: (String value) 
              return _nic = value;
            ,
          ),
        ),
      ],
    );
  
  
  
  @override
  Widget build(BuildContext context) 
    return Scaffold(
      appBar: AppBar(
        automaticallyImplyLeading: false,
        leading: IconButton(
          icon:Icon(Icons.close),
          onPressed:() => Navigator.of(context).pop(null),
        ),
        centerTitle: true ,
        title: Text('Edit Profile',
          style: TextStyle(
            color: Colors.white,
            fontSize: 20.0,
            fontWeight: FontWeight.bold,
          ),
        ),
        actions: <Widget>[
          GestureDetector(
            onTap: ()async
              print('Profile Updated!!!');
            ,
            child: Container(
              padding: EdgeInsets.only(top: 17, right: 25),
              child: Text(
                'SAVE',
                style: TextStyle(fontSize: 18),
              ),
            ),
          ),
        ],
      ),
      body: AnnotatedRegion<SystemUiOverlayStyle>(
        value: SystemUiOverlayStyle.light,
        child: GestureDetector(
          onTap: () => FocusScope.of(context).unfocus(),
          child: Stack(
            children: <Widget>[
              Container(
                height: double.infinity,
                width: double.infinity,
                decoration: BoxDecoration(
                  gradient: LinearGradient(
                    begin: Alignment.topCenter,
                    end: Alignment.bottomCenter,
                    colors: [
                      Color(0xFF73AEF5),
                      Color(0xFF61A4F1),
                      Color(0xFF478DE0),
                      Color(0xFF398AE5),
                    ],
                    stops: [0.1, 0.4, 0.7, 0.9],
                  ),
                ),
              ),
              Container(
                height: double.infinity,
                child: SingleChildScrollView(
                  physics: AlwaysScrollableScrollPhysics(),
                  padding: EdgeInsets.symmetric(
                    horizontal: 35.0,
                    vertical: 5.0,
                  ),
                  child: Form(
                    key: formKey,
                    child: Column(
                      mainAxisAlignment: MainAxisAlignment.center,
                      children: <Widget>[
                        SizedBox(height: 15.0),
                        imageAvatar,
                        _NameTextField(_name),
                        SizedBox(
                          height: 15.0,
                        ),
                        _NICTextField(),
                        SizedBox(
                          height: 15.0,
                        ),
                      ],
                    ),
                  ),
                ),
              )
            ],
          ),
        ),
      ),
    );
  

我是 Flutter 和 Firebase 数据库的新手，任何人都可以帮助我。这是我的 Uni 项目。 谢谢

【参考方案1】：

要检索数据，请尝试以下操作：

db = FirebaseDatabase.instance.reference().child("Users");
db.once().then((DataSnapshot snapshot)
  Map<dynamic, dynamic> values = snapshot.value;
     values.forEach((key,values) 
      print(values["Email"]);
    );
 );

添加对节点Users 的引用，然后迭代并检索数据。要检索一个特定用户的数据，您需要使用查询，因为您没有使用 firebase auth：

db.orderByChild("Full Name").equalTo("Dasun Shanaka").once()