Flutter rangeerror (index): invalid value: valid value range is empty: 0

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Flutter RangeError (index)

A ‘RangeError (index)’ in Flutter occurs when you are trying to access an index value that is out of the valid range.

The error message itself provides useful information such as ‘valid value range is empty’ and the actual value you provided.

Let’s look at an example to understand this error better:

    
      List colors = ['red', 'green', 'blue'];
      print(colors[3]);

In this example, we have a list of colors with three elements. However, when we try to access the fourth element using index 3, it exceeds the valid range of indices (0 to 2). Hence, it throws a RangeError with the message ‘valid value range is empty’.

To fix this error, you need to ensure that the index value you provide is within the valid range of indices.

    
      List colors = ['red', 'green', 'blue'];
      if (index >= 0 && index < colors.length) {
        print(colors[index]);
      } else {
        print('Invalid index!');
      }

In the corrected example, we first check if the index is within the valid range using conditional statements. If it is, we can safely access the element at that index. Otherwise, we handle the 'Invalid index!' case separately.

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