Flutter: Firebase How to change the query and the content - firebase

Question

I am trying to change the query according to the selected community.
When you select the community you must show the content of this community.
I have found a solution but I do not think it is the right one, because the application has 39 countries.
Those 39 require you to have a query for each one and there are many lines of code.
I hope there is some better solution than what I found.
GIF APP
- The error that appears is because there is no other country.
SearchClub.dart
This is the function that returns a query related to the countries.
I want to use one and not make several queries for each country.
searchClubs(TextEditingController countryChanged) {
var widgetFireUpdate;
setState(() {
if(countryChanged.text == 'SPAIN') {
widgetFireUpdate = new FirebaseAnimatedList(
query: FirebaseDatabase.instance.reference().child(widget.player.platform).child("CLUB").orderByChild('country').equalTo(countryChanged.text),
sort: (a, b) => a.value['createdDate'].compareTo(b.value['createdDate']),
reverse: true,
shrinkWrap: true,
defaultChild: new CircularProgressIndicator(),
itemBuilder: (BuildContext context, DataSnapshot snapshot,
Animation<double> animation, int index) {
return new StreamBuilder<Event>(
stream: itemRef2.orderByKey().onValue,
builder: (context, AsyncSnapshot<Event> snapshot2){
if(snapshot2.hasData) {
try {
return new Container(
decoration: new BoxDecoration(
color: Colors.grey[300],
),
child: new ListTile(
leading: snapshot.value['logoURL'].toString().indexOf('images/assets/logo_notfound.png') == -1 ? new CachedNetworkImage(imageUrl: snapshot.value['logoURL'], width: MediaQuery.of(context).size.width/8) : new Image.asset(snapshot.value['logoURL'], width: MediaQuery.of(context).size.width/8),
title: new Text(snapshot.value['name'].toUpperCase(), style: new TextStyle(color: Colors.black, fontWeight: FontWeight.bold, fontSize: MediaQuery.of(context).size.width/30)),
subtitle: new RichText(
text: new TextSpan(
children: <TextSpan>[
new TextSpan(text: "CAPITÁN:", style: new TextStyle(color: Colors.black, fontSize: MediaQuery.of(context).size.width/35, fontWeight: FontWeight.bold)),
new TextSpan(text: " ${snapshot.value['captain'].toUpperCase()}", style: new TextStyle(color: Colors.black, fontSize: MediaQuery.of(context).size.width/35)),
]
),
),
),
);
}catch(e) {
return new Container();
}
} else if(snapshot2.hasError){
return new Container();
} else {
return new Container(
child: new Center(
child: new CircularProgressIndicator(
backgroundColor: Colors.red,
),
),
);
}
},
);
},
);
} else if(countryChanged.text == 'BRAZIL') {
widgetFireUpdate = new FirebaseAnimatedList(
query: FirebaseDatabase.instance.reference().child(widget.player.platform).child("CLUB").orderByChild('country').equalTo(countryChanged.text),
sort: (a, b) => a.value['createdDate'].compareTo(b.value['createdDate']),
reverse: true,
shrinkWrap: true,
defaultChild: new CircularProgressIndicator(),
itemBuilder: (BuildContext context, DataSnapshot snapshot,
Animation<double> animation, int index) {
return new StreamBuilder<Event>(
stream: itemRef2.orderByKey().onValue,
builder: (context, AsyncSnapshot<Event> snapshot2){
if(snapshot2.hasData) {
try {
return new Container(
decoration: new BoxDecoration(
color: Colors.grey[300],
),
child: new ListTile(
leading: snapshot.value['logoURL'].toString().indexOf('images/assets/logo_notfound.png') == -1 ? new CachedNetworkImage(imageUrl: snapshot.value['logoURL'], width: MediaQuery.of(context).size.width/8) : new Image.asset(snapshot.value['logoURL'], width: MediaQuery.of(context).size.width/8),
title: new Text(snapshot.value['name'].toUpperCase(), style: new TextStyle(color: Colors.black, fontWeight: FontWeight.bold, fontSize: MediaQuery.of(context).size.width/30)),
subtitle: new RichText(
text: new TextSpan(
children: <TextSpan>[
new TextSpan(text: "CAPITÁN:", style: new TextStyle(color: Colors.black, fontSize: MediaQuery.of(context).size.width/35, fontWeight: FontWeight.bold)),
new TextSpan(text: " ${snapshot.value['captain'].toUpperCase()}", style: new TextStyle(color: Colors.black, fontSize: MediaQuery.of(context).size.width/35)),
]
),
),
),
);
}catch(e) {
return new Container();
}
} else if(snapshot2.hasError){
return new Container();
} else {
return new Container(
child: new Center(
child: new CircularProgressIndicator(
backgroundColor: Colors.red,
),
),
);
}
},
);
},
);
}
});
return widgetFireUpdate;
}
// OPEN LIST COMMUNITY
Widget _buildBottomPicker() {
final FixedExtentScrollController scrollController = new FixedExtentScrollController();
return new Container(
height: MediaQuery.of(context).size.height/3.5,
color: CupertinoColors.white,
child: new DefaultTextStyle(
style: const TextStyle(
color: CupertinoColors.black,
fontSize: 22.0,
),
child: new SafeArea(
child: new CupertinoPicker(
scrollController: scrollController,
itemExtent: MediaQuery.of(context).size.height/15,
magnification: 0.7,
diameterRatio: 0.5,
backgroundColor: CupertinoColors.white,
onSelectedItemChanged: (int index) {
setState(() {
_comunidad.text = _comunidades[index];
_imgComunidad = _imgComunidades[index];
});
},
children: new List<Widget>.generate(_comunidades.length, (int index) {
return new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Text(_comunidades[index]),
],
);
}),
),
),
),
);
}
#override
Widget build(BuildContext context) {
return new Scaffold(
key: _scaffoldKey,
appBar: searchBar.build(context),
body: new Container(
color: widget.themeConsole,
child: new Column(
children: <Widget>[
new Card(
elevation: 0.0,
color: Colors.grey[50],
child: new Container(
child: new Row(
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
new Container(
width: MediaQuery.of(context).size.width/1.35,
child: new TextFormField(
controller: _comunidad,
style: new TextStyle(color: Colors.white),
enabled: false,
decoration: new InputDecoration(
labelText: 'Community:',
labelStyle: new TextStyle(color: Colors.white),
icon: new Image.asset(_imgComunidad, width: 24.0),
filled: true,
fillColor: Colors.grey[800],
),
validator: (String value){
player.country = value;
},
),
),
new IconButton(
icon: new Icon(Icons.flag, color: Colors.grey[800], size: 30.0,),
color: Colors.black,
onPressed: ()async {
await showModalBottomSheet<void>(
context: context,
builder: (BuildContext context) {
return _buildBottomPicker();
},
);
},
),
],
),
),
),
new Flexible(child: searchClubs(_comunidad))
],
)
),
);
}
SearchClub Complete: https://pastebin.com/zbeU6M1u

Answer 1

From what I have understood, you are using firebase real time database where you have child name as country and have data inside that node. You want to make queries in such a way that when you select a country, that particular query should be made like when selecting Argentina everything inside Argentina in your database should be called.
Store value of country names in a list and make a string for calling countries.
String country="";
List<String> country_name=["Argentina","Brazil","Spain"....];
Now on press function can be like this-
onPressed: () {
setState(() {
country=country_name[1];//example
});
country_call();
}
This will help us when we change the country name.
Lastly make changes in your firebase reference-
Future<void> country_call()async{
final FirebaseDatabase database = FirebaseDatabase().instance();
setState(() {
itemRef = database.reference().child(country);
itemRef.onChildAdded.listen(_onEntryAdded);
itemRef.onChildChanged.listen(_onEntryChanged);
});
}
By changing you can call different queries without writing for 39 different countries. If you are using a list view to show our data, make sure to empty it in country_call function. That can be done by simply equating it to null list("[]").
I was searching for something similar but could not find anything on the website. I used this approach to fix my problem. I hope it was helpful for you too.