FirebaseAnimatedList query when query don't have data to fetch

user_7290486 0
Viewed 847

I'm super new to flutter and firebase and trying to query some data from the firebase realtime database using the FirebaseAnimatedList in the example code below I try to pass this.userid to fetch data according to the value being passed but sometimes database might not have data according to what's being passed. I just want to know how to handle such cases and show a feedback saying there's no data that matched the query. It's basically a search where it might not have values that user look for.

example code: 


    FirebaseAnimatedList(
            query: ref.child("users").orderByChild("id").equalTo(this.userid),
            itemBuilder: (BuildContext context, DataSnapshot snapshot,
                Animation<double> animation, int index) {
              return SizeTransition(
                sizeFactor: animation,
                axis: Axis.horizontal,
                axisAlignment: -0.8,
                child: Column(
                  textDirection: TextDirection.ltr,
                  verticalDirection: VerticalDirection.down,
                  children: <Widget>[
                    SizedBox(
                      height: 100.0,
                    ),
                    Text(
                      "User ID : " + snapshot.value["id"],
                    ),
                    SizedBox(
                      height: 50.0,
                    ),
                  ],
                ),
              );
            }));
firebase-realtime-database firebase dart flutter
2 Answers

snapshot is of type DataSnapshot, therefore you can check if data exists or not by using the property exists:

itemBuilder: (BuildContext context, DataSnapshot snapshot,
                Animation<double> animation, int index) {
            if(!snapshot.exists){
                  return Text("No Data");
            } 
            else {
              return SizeTransition(
                sizeFactor: animation,
                axis: Axis.horizontal,
                axisAlignment: -0.8,
                child: Column(
                  textDirection: TextDirection.ltr,
                  verticalDirection: VerticalDirection.down,
                  children: <Widget>[
                    SizedBox(
                      height: 100.0,
                    ),
                    Text(
                      "User ID : " + snapshot.value["id"],
                    ),
                    SizedBox(
                      height: 50.0,
                    ),
                  ],
                ),
              );
             } 
            }

Check the following for more info:

https://pub.dev/documentation/firebase_dart/latest/firebase_dart/DataSnapshot-class.html

user_70154000 
Query q=ref.child("users").orderByChild("id").equalTo(this.userid);
q==null?Center(child: CircularProgressIndicator()): FirebaseAnimatedList(
  query: ref.child("users").orderByChild("id").equalTo(this.userid),
  itemBuilder: (BuildContext context, DataSnapshot snapshot,
    Animation<double> animation, int index) {
  return SizeTransition(
    sizeFactor: animation,
    axis: Axis.horizontal,
    axisAlignment: -0.8,
    child: Column(
      textDirection: TextDirection.ltr,
      verticalDirection: VerticalDirection.down,
      children: <Widget>[
        SizedBox(
          height: 100.0,
        ),
        Text(
          "User ID : " + snapshot.value["id"],
        ),
        SizedBox(
          height: 50.0,
        ),
      ],
    ),
  );
}));
user_144059290
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