[Solved] RangeError (index): Invalid value: Valid value range is empty: 0

Hello Guys How are you all? Hope You all are fine. When I was trying to run my flutter app and suddenly I get the following error in my stack track. RangeError (index): Invalid value: Valid value range is empty: 0 in a flutter. So today Here I come with all possible solutions for this error.

We are providing you all possible solutions to solve this error. let’s start this article without wasting your time.

How RangeError (index): Invalid value: Valid value range is empty: 0 Error Occurs ?

I have two methods one for fetchUserData and the second for fetchUserPost. the first time it is showing a red screen error and then after 2 seconds automatically it is loading the list. I got this error in my stack track.

RangeError (index): Invalid value: Valid value range is empty: 0

Here is my code

userData = await fetchUserData();
userPost = await fetchUserPost();

Text(userData[0]['userName']); // RangeError (index): Invalid value: Valid value range is empty: 0

How to Solve RangeError (index): Invalid value: Valid value range is empty: 0 Error?

Solution 1: Give Default Value

The problem can be that you are trying to access a variable/array that is not ready yet (maybe because the future/api call is not finished)

A quick workaround could be to check the length of the array or check for null, example:

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

Solution 2: Null safe

This error occurs on retrieving the value for an index that doesn’t exist in the List. For example:

List userData = [];
userData[0]; // <-- Error since there's no element at index 0 in the list

Check if the the List is not null and has the element at index:

var userData = nullableList;
var name = '';

if (userData != null && userData.length != 0) {
  name = userData [0]['userName']; // You can safely access the element here. 
}

Solution 3: User asynchronous

you getting data from fetchUserData method, If you are getting data in fetchUserData metod. then you should follow this

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

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

Summery

So, It’s All About This Error. I hope this tutorial helps you to Solve your error. Please Comment Below if You stucks anywhere with my code. And please comment below on which solution worked for you. Thank You.

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