RangeError (index): Invalid value: Not in range 0..2, inclusive: 3

Question

I am getting a flutter Range error despite putting a child count on the widget. This is the initial call for getting the elements from the logic.

The logic works fine and it maps properly but it's showing a range error despite all the length's being finite. It works fine if I put it in a list view but I need the entire screen scrollable hence the need for a sliver List builder

I added it. Can you please help me work it out. The backend is fine and I have no problem mapping it. Still it's not displaying — Vedant Yogesh, Mar 28 '20 at 20:18

score 0 · Answer 1 · answered Mar 28 '20 at 20:32

0

change this

if (res == null) {
       return;
 }

to

 if (res == null) {
    // return empty list not null ( since null has no lenght) 
   return <MenuItem>[];
 }

answered Mar 28 '20 at 20:32

Loïc Fonkam

2,284
11
25

1

I found the solution. The number of items in menuCat and menuData is different. So according to the Sliver builder since the headings have a length of 4 and the count is 28 hence the issue. All I had to do was put menuCat.length in the child count – Vedant Yogesh Mar 29 '20 at 18:56

score 0 · Answer 2 · answered Mar 29 '20 at 19:00

0

The answer is that among the two different lengths in StickyHeader, we must pick the one less in number i.e. the menuCat.length(Header length) in the child count.

answered Mar 29 '20 at 19:00

Vedant Yogesh

19
3

RangeError (index): Invalid value: Not in range 0..2, inclusive: 3

2 Answers2