How to Resolve Invalid Value Valid Value Range is Empty In Flutter ?

· 4 min read
How to Resolve Invalid value Valid Value Range is Empty In Flutter
How to Resolve Invalid value Valid Value Range is Empty In Flutter

ListView Widget is used while fetching data from API Generally user displays data into ListView.Builder Widget is used. So in this article, We are going to discuss How to Resolve Invalid Value Valid Value Range is Empty In Flutter?

How to Resolve Invalid value Valid Value Range is Empty In Flutter?

Generally, this kind of error occurs when the user doesn’t provide a length to ListView.Builder Widget. We can also try code snippet like the below:

Widget build(context) {
    try{
      if (isFirst == true) {
        fetchImage();
        fetchCategories(context);
        isFirst = false;
      }
    }catch(Exception){

    }

    return MaterialApp(
      home: Scaffold(
        backgroundColor: Colors.black,
        appBar: AppBar(
          title: Text('Lets see images!'),
        ),
        body: new Column(
          children: <Widget>[
            new Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: <Widget>[
                new InkResponse(
                    child: new Column(
                      children: <Widget>[
                        Padding(
                          padding: EdgeInsets.all(10.0),
                          child: new Image.asset(
                            catimages?.elementAt(0) ?? "",
                            width: 60.0,
                            height: 60.0,
                          ),
                        ),
                        new Text(
                          categoriesText?.elementAt(0) ?? "",
                          style: TextStyle(color: Colors.white),
                        ),
                      ],
                    ),
                    onTap: () {
                      debugPrint("on tv clikced");
                      widget.fetchApI.fetchSubCategories(context, 6);
                    }),
                new InkResponse(
                  child: new Column(
                    children: <Widget>[
                      Padding(
                        padding: EdgeInsets.all(10.0),
                        child: new Image.asset(
                          catimages?.elementAt(1) ?? "",
                          width: 60.0,
                          height: 60.0,
                        ),
                      ),
                      new Text(
                        categoriesText?.elementAt(1) ?? "",
                        style: TextStyle(color: Colors.white),
                      ),
                    ],
                  ),
                  onTap: () {
                    debugPrint("on moview clicked");
                    widget. fetchApI.fetchSubCategories(context, 7);
                  },
                ),
                new InkResponse(
                  child: new Column(
                    children: <Widget>[
                      Padding(
                        padding: EdgeInsets.all(10.0),
                        child: new Image.asset(
                          catimages?.elementAt(2) ?? "",
                          width: 60.0,
                          height: 60.0,
                        ),
                      ),
                      new Text(
                       categoriesText?.elementAt(2) ?? "",
                        style: TextStyle(color: Colors.white),
                      ),
                    ],
                  ),
                  onTap: () {
                    debugPrint("on news clicked");
                    widget.fetchApI.fetchSubCategories(context, 10);
                  },
                ),
                new InkResponse(
                  child: new Column(
                    children: <Widget>[
                      Padding(
                        padding: EdgeInsets.all(10.0),
                        child: new Image.asset(catimages?.elementAt(3) ?? "",
                            width: 60.0, height: 60.0),
                      ),
                      new Text(
                        categoriesText?.elementAt(3) ?? "",
                        style: TextStyle(color: Colors.white),
                      ),
                    ],
                  ),
                  onTap: () {
                    debugPrint('on shows clicked');
                    widget.fetchApI.fetchSubCategories(context, 8);
                  },
                ),
                new InkResponse(
                  child: new Column(
                    children: <Widget>[
                      Padding(
                        padding: EdgeInsets.all(10.0),
                        child: new Image.asset('assets/live_icon.png',
                            width: 60.0, height: 60.0),
                      ),
                      new Text(
                        'Live',
                        style: TextStyle(color: Colors.white),
                      ),
                    ],
                  ),
                  onTap: () {
                    debugPrint('on live clicked');
                  },
                ),
              ],
            ),
            ImageList(images,widget.fetchApI),
          ],
        ),
      ),
    );
  }
}

A quick workaround could be check for the length of the array or length of a widget.

Text( (myArray?.length > 0 ? myArray[0] : '') );

FetchAPI and is an asynchronous method so it takes time to get data from JSON and in the begging FetchAPI is empty, so it gives an error of range. you can make FetchAPI method asynchronous using await and async* and while calling that method use .then method and then access values.

fetchApI().then((){ // access fetchApI over here });

Conclusion:

In this article, We have been through Resolve Invalid value Valid Value Range is Empty In Flutter?

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