I am trying to only display certain data from a collection. In my example, I only want to show data in the list where the collection in name on firebase is equal to the name of the widget. I am unable to solve this problem
Expanded(
child: Container(
child: FutureBuilder(
future: getPosts(),
builder: (_,snapshot){
if(snapshot.data["name"]== widget.info.name){
return ListView.builder(
itemCount:
x,
itemBuilder: (_,index){
return ListTile(
title: Text(snapshot.data[index].data["name"]),
);
});
Expanded(
child: Container(
child: FutureBuilder(
future: getPosts(),
builder: (_,snapshot){
return ListView.builder(
itemCount:
snapshot.data,
itemBuilder: (_,index){
if(snapshot.data["name"]== widget.info.name){
return ListTile(
title:Text(snapshot.data[index].data["name"]),
);
}else{
return Container();
}
})}))
);
A better option will be to pass the widget name in the getPosts() function you defined and update the firebase query to do the filtering. This way it be much faster as firebase does the require indexing and will do the filtering in O(len(filtered_elements)) rather than current time complexity of O(len(all_elements)).
Related
This is what I am doing now.
Main Page:
I would like to make it same like this picture.Example:
I have tried couple ways and widget to build it but couldn't figure it out. Also, I want to retrieve the data from the Firebase and show them as the content.
Code 1: https://pastebin.com/A0nK1riQ
Code 2: https://pastebin.com/i1T7gBNy
Widget build(BuildContext context) {
return Container(
child: StreamBuilder(
stream: _products.snapshots(),
builder: (context, AsyncSnapshot<QuerySnapshot> streamSnapshot) {
if (streamSnapshot.hasData) {
return ListView.builder(
itemCount: streamSnapshot.data!.docs.length,
itemBuilder: (context, index) {
final DocumentSnapshot documentSnapshot =
streamSnapshot.data!.docs[index];
return Container(
margin: const EdgeInsets.all(10),
child: ListTile(
title: Text(documentSnapshot['name']),
subtitle: Text(documentSnapshot['price'].toString()),
trailing: SizedBox(
width: 100,
),
),
);
});
}
return SizedBox.shrink();
}),
);
}
You may use GridView.builder
https://api.flutter.dev/flutter/widgets/GridView-class.html
and in gridview build use column
According to me, first you have to check which NavigationRail icon clicked then put the condition on it's GestureDetector like
// global variable
String itemClickedValue = "";
then set the value in it according to user click
itemClickedValue = "first";
then check the condition while fetching data like
if(itemClickedValue.compareTo("first") == 0){
// pass that documentId or api and then show in list
}
In my Flutter app, I need to display two lists that are coming from the database, but I am having trouble getting both lists to display on the same screen. I am using two FutureBuilder widgets, but the first list is displaying correctly while the second list is still loading.
Here is the code I am using:
var future1 = FutureBuilder<List<QuranTextModel>>(
future: database.getQuranText(),
builder: (context, snapshot) {
if(snapshot.hasData){
return ScrollablePositionedList.builder(
itemScrollController: scrollToIndex,
itemCount: snapshot.data!.length,
initialScrollIndex: widget.position,
itemBuilder: (context, index) {
// Build the list item widget here
});
}else{
return const Center(child: CircularProgressIndicator(),);
}
}
);
var future2 = FutureBuilder<List<UrduTextModel>>(
future: database.getUrduTranlation(),
builder: (context, snapshot) {
if(snapshot.hasData){
return ScrollablePositionedList.builder(
itemScrollController: scrollToIndex,
itemCount: snapshot.data!.length,
initialScrollIndex: widget.position,
itemBuilder: (context, index) {
// Build the list item widget here
});
}else{
return const Center(child: CircularProgressIndicator(),);
}
}
);
Column(
children: [
SizedBox(
height: 200,
child: future1,
),
SizedBox(
height: 200,
child: future2,
),
],
)
The first FutureBuilder is used to build a list of QuranTextModel objects, and the second FutureBuilder is used to build a list of UrduTextModel objects. I am using a Column widget to display both lists, with each list contained within a SizedBox widget to give it a fixed height.
The issue I am having is that only the first list is displaying correctly, while the second list is still loading. How can I get both lists to display on the same screen?
Thank you for any help you can provide!
SingleChildScrollView(
child: Column(
children: [
SizedBox(
height: 200,
child: future1),
SizedBox(height: 200,child: future2,)
],
),
),
Try this.
also you have to check your future status before populate you can check that by using
if (snap.connectionState == ConnectionState.done) { your code. you can check does snpa has data in it. }
connection state has deferent states that can help you to make your UI more interactive
I'm new to flutter and I want to organise the elements that I get from Firestore in a list with StickyHeaders. I would like to do it with an itemBuilder and the snapshot I get from the database.
My problem is the itemBuilder builds each item separately and has to be returned, but StickyHeader needs to have all items added as children.
How can I achieve this? Just as a reference I paste my code without the StickyHeader. buildItemBubble returns a Card Widget.
StreamBuilder(
stream: buildSnapshots(_filters),
builder: (context, snapshot) {
if (!snapshot.hasData)
return Center(
child: CircularProgressIndicator(),
);
return snapshot.data.documents.length == 0
? Center(child: Text('It\s empty here...'))
: CupertinoScrollbar(
child: ListView.builder(
key: new PageStorageKey('randomkey'),
shrinkWrap: true,
padding: const EdgeInsets.all(10.0),
itemCount: snapshot.data.documents.length,
itemBuilder: (ctx, i) =>
buildItemBubble(snapshot, i),
),
);
},
)
I have the following widget which builds a to-do list from a subcollection of a task given its document ID. The code is working fine.
Widget buildFoodList() {
return SizedBox(
child: Container(
padding: const EdgeInsets.all(10.0),
child: StreamBuilder<QuerySnapshot>(
stream: Firestore.instance.collection('tasks').document(documentID).collection('todo')
.snapshots(),
builder: (BuildContext context,
AsyncSnapshot<QuerySnapshot> snapshot) {
if (snapshot.hasError)
return new Text('Error: ${snapshot.error}');
switch (snapshot.connectionState) {
case ConnectionState.waiting:
return new Text('Loading...');
default:
return new ListView.builder(
shrinkWrap: true,
itemCount: snapshot.data.documents.length,
itemBuilder: (context, index) {
DocumentSnapshot ds = snapshot.data.documents[index];
return new Row(
children: <Widget>[
Expanded (child:Text(ds['deadline'].toString()) ),
Expanded (child:Text(ds['description']) ),
Expanded (child:Text("\$"+ds['quantity'].toString()) ),
],
);
},
);
}
},
)
),
);
}
As you can see, I am using a StreamBuilder. However, I know that the subcollection is not going to change. So the question is whether using StreamBuilder is an overkill, because using stream to listen can be a waste of resources and access to Firebase. More importantly, the cost of using Firebase is calculated on an access basis.
To summarise, the question is whether using StreamBuilder is necessary. If not, what is the alternative approach which can help to avoid unnecessary access to Firebase.
Thanks.
StreamBuilder is necessary in apps where you need to fetch any update , insert or delete in a firebase collection ( in this case ). An alternative can be the FutureBuilder that fetch the data once and then you can wrap in a Swipe to refresh ( and the user decides when needs to see new data).
I'm trying to create a nested ListView, but don't know, if I can combine 2 streambuilders in a nested view, as it doesn't work. In the second StreamBuilder with the subcollection query, no data seems to be returned and I can't figure out why.
When I hardcode the document id I don't get any error, but still the query doesn't seem to return any data.
Does anybody know, how to construct a nested listview with streambuilders and Firestore?
List<Widget> buildStreamedListView() {
return [ StreamBuilder(
stream: Firestore.instance.collection('course')
.document(widget.data.documentID)
.collection('section')
.snapshots(),
builder: (context, snapshot) {
if (!snapshot.hasData) return const Text("Loading...");
return Expanded(child: ListView.builder(
itemCount: snapshot.data.documents.length,
itemBuilder: (context, index) {
//return buildListItem(context, snapshot.data.documents[index]);
return Card(
child: ExpansionTile(
title: Text(snapshot.data.documents[index]['name']),
children: <Widget>[
StreamBuilder(
stream: Firestore.instance.collection('course')
.document(widget.data.documentID)
.collection('section')
.document('4CjAZEQ416NYpu3ra3OE')
.collection('page')
.snapshots(),
builder: (context, snap) {
return ListView.builder(
shrinkWrap: true,
itemCount: snap.data.documents.length,
itemBuilder: (context, index) {
return Text('Hello you');
}
);
}
),
],
),
);
}
));
},
)];
}
The reason that I had strange errors was, that in the second builder function I didn't add the following code:
if (!snapshot.hasData) return const Text("Loading...");
Once I added it, it worked. Seems the data was just not ready yet, hence it couldn't be read and hence the error.
Be careful to also test for snap.hasData() in your nested StreamBuilder.