firebase - 检查 Flutter Firestore 中是否已存在字段
问题描述
我有一个名为company
. 所有公司都将像我的屏幕截图一样存储。
当我添加另一家公司时,我想检查是否name
已经存在。如何执行?
在这里,“Nova”和“Tradetech”是两家公司。
当我再次尝试在该字段中添加“Nova”name: "nova"
时,我想显示一条通知:“公司已经存在!” .
解决方案
我已经用以下代码解决了这个问题,谢谢你的帮助!
在我曾经找到的以下代码中
1)文件是否存在?
2)密钥是否存在?
3)值是否存在?
SIMPLE METHOD
//////////////////////////////////////////////////////////////////////
import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'dart:async';
String myText1 = 'temp1';
String myText2 = 'temp2';
String myText3 = 'temp3';
String myText4 = 'temp4';
String myText5 = 'temp5';
String myText6 = 'temp6';
StreamSubscription<DocumentSnapshot> subscription;
final DocumentReference documentReference =
Firestore.instance.document("company/Nova");
class Clean extends StatefulWidget {
@override
_CleanState createState() => _CleanState();
}
class _CleanState extends State<Clean> {
@override
void initState() {
super.initState();
subscription = documentReference.snapshots().listen((datasnapshot) {
//FINDING A SPECIFICDOCUMENT IS EXISTING INSIDE A COLLECTION
if (datasnapshot.exists) {
setState(() {
myText1 = "Document exist";
});
} else if (!datasnapshot.exists) {
setState(() {
myText2 = "Document not exist";
});
}
//FINDING A SPECIFIC KEY IS EXISTING INSIDE A DOCUMENT
if (datasnapshot.data.containsKey("name")) {
setState(() {
myText3 = "key exists";
});
} else if (!datasnapshot.data.containsKey("name")) {
setState(() {
myText4 = "key not exists";
});
}
//FINDING A SPECIFIC VALUE IS EXISTING INSIDE A DOCUMENT
if (datasnapshot.data.containsValue("nova")) {
setState(() {
myText5 = "value exists";
});
} else if (!datasnapshot.data.containsValue("nova")) {
setState(() {
myText6 = "value not exists";
});
}
});
}
@override
Widget build(BuildContext context) {
return Column(
children: <Widget>[
new Text(myText1),
new Text(myText2),
new Text(myText3),
new Text(myText4),
new Text(myText5),
new Text(myText6),
],
);
}
}
基于我现有代码的旧复杂方法 /////////////////////////////////// ///////////////
概念
它有一个搜索栏,当你输入它会显示公司名称,即存在或不存在
一个Card
和一个RaisedButton
。我在Firestore中使用小写字母以避免搜索错误。我已将TextFormField
输出强制为小写toLowercase()
。您可以将其更改为您自己的文本格式。
代码
//if the name is not existing it will show a raised button so u can clcik on that to
//go to a COMPANY ADDING PAGE,otherwise it will only show a **CARD** so that you
//can't go to the next page to add your company
//code:
import 'package:flutter/material.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'dart:async';
import './fullscreen.dart';
const blue = 0xFF3b78e7;
String filter = '';
StreamSubscription<DocumentSnapshot> subscription;
final TextEditingController _usercontroller = new TextEditingController();
class CheckAvail extends StatefulWidget {
@override
HomeState createState() => HomeState();
}
class HomeState extends State<CheckAvail> {
@override
Widget build(BuildContext context) {
return Scaffold(
resizeToAvoidBottomPadding: false,
body: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
// CHILD1
new Flexible(
child: StreamBuilder(
stream: Firestore.instance
.collection('company')
.where('name', isGreaterThanOrEqualTo: filter.toLowerCase())
.limit(1)
.snapshots(),
builder: (BuildContext context,
AsyncSnapshot<QuerySnapshot> snapshot) {
if (!snapshot.hasData) {
return new Column(
children: <Widget>[
new Card(
elevation: 5.0,
child: new Image.asset('assets/progress.gif'),
)
],
);
} else {
return FirestoreListView1(documents: snapshot.data.documents);
}
},
),
),
new Card(
elevation: 0.0,
color: Colors.white,
shape: new RoundedRectangleBorder(
borderRadius: BorderRadius.circular(60.0)),
child: Container(
padding: new EdgeInsets.only(left: 8.0),
child: new TextField(
controller: _usercontroller,
onChanged: (String z) {
setState(() {
filter = z;
});
},
decoration: const InputDecoration(
hintText: "Search...",
hintStyle: TextStyle(
fontFamily: 'roboto',
color: Colors.black38,
fontSize: 16.0,
letterSpacing: -0.500),
fillColor: Colors.white,
border: InputBorder.none,
),
),
),
),
],
),
backgroundColor: Color(blue),
);
}
}
////////////////////////////////////////////////////////////////////////////////////////////////////////////////
class FirestoreListView1 extends StatelessWidget {
final List<DocumentSnapshot> documents;
FirestoreListView1({this.documents});
@override
Widget build(BuildContext context1) {
return ListView.builder(
itemCount: documents.length,
padding: new EdgeInsets.all(1.0),
itemBuilder: (BuildContext context1, int index) {
String name = documents[index].data['name'];
if (name.contains(filter.toLowerCase()) &&
name.length == filter.length) {
return new Container(
padding: new EdgeInsets.only(top: 45.0),
child: new Card(
child: new Text(
"Error:Already a Company Exists with this name\nTry another name")),
);
} else {
return (filter.length >= 1)
? new Container(
padding: new EdgeInsets.only(top: 15.0),
child: new RaisedButton(
onPressed: () => Navigator.push(
context1,
new MaterialPageRoute(
builder: (context1) => new NextPage(
value1: name,
))),
disabledColor: Colors.white,
child: new Text(
"Good!You can use this company name",
),
),
)
: new Container(padding: new EdgeInsets.only(top: 250.0),
child: new Card(child: new Text("CHECK IF YOUR COMPANY NAME \n AVAILABLE OR NOT",style: new TextStyle(fontSize: 20.0),)),
);
}
});
}
}
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