ScrollExtent is negative in flutter

Question

Getting a very pesky error on this segment of my Flutter app and no clue why:

child: GridView.builder(
    gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: 1,
        childAspectRatio: 4 / 3,
        mainAxisSpacing: 30.0,
        crossAxisSpacing: 20.0),
    padding: EdgeInsets.only(left: 20),
    scrollDirection: Axis.horizontal,
    itemCount: products.length,
    itemBuilder: (context, i) => ChangeNotifierProvider.value(
      value: products[i],
      child: Consumer<Product>(
        builder: (context, product, _) {
          return ProductCard(
              product: product,
              onSelected: (prod) {
                setState(() {
                  products.forEach(
                    (item) {
                      item.isSelected = false;
                    },
                  );
                  prod.isSelected = true;
                });
here's the error: SliverGeometry is not valid: The "scrollExtent" is negative.geometry: SliverGeometry(scrollExtent: -10.0, paintExtent: 20.0, maxPaintExtent: -10.0, cacheExtent: 20.0)
scrollExtent: -10.0
paintExtent: 20.0
maxPaintExtent: -10.0
cacheExtent: 20.0

padding: EdgeInsets(20.0, 0.0, 0.0, 0.0)

This error is preventing emulation on Android even though the apk is installed but it just won't run. It runs on iOS but the error remains.

score 5 · Answer 1 · answered Feb 19 '22 at 19:00

Pretty sure you've sorted it out already but as I don't see any accepted answer I'll leave mine to be useful to others.

I was in the same situation and I had the same problem, dough in the cross axis. The problem is that you're providing both mainAxisSpacing: 30.0 and crossAxisSpacing: 20.0 values. With a crossAxisCount: 1 you're not using the main axis so mainAxisSpacing throws the infamous SliverGeometry is not valid: The "scrollExtent" is negative.error. Independently from your scrollingDirection you should only pass the crossAxisSpacing value.

child: GridView.builder(
    gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisCount: 1,
        childAspectRatio: 4 / 3,
        crossAxisSpacing: 20.0),
    padding: EdgeInsets.only(left: 20),
    scrollDirection: Axis.horizontal,
    itemCount: products.length,
    itemBuilder: (context, i) => ChangeNotifierProvider.value(
      value: products[i],
      child: Consumer<Product>(
        builder: (context, product, _) {
          return ProductCard(
              product: product,
              onSelected: (prod) {
                setState(() {
                  products.forEach(
                    (item) {
                      item.isSelected = false;
                    },
                  );
                  prod.isSelected = true;
                });

Satyam · Answer 2 · 2022-06-20T16:30:30.487

3

It is my code that was causing the same, Exception before exception

I searched a lot, in short, it is how i solve it

What i did to fix it

In my case, changing gridDelegate, my exception is fixed!

Note: Don't use any Mathematical operation like (/,*) that may produce a double value!!!

Give a like if you find it Useful! :)

edited Jun 20 '22 at 16:30

answered Mar 23 '21 at 10:25

Satyam

131
9

score 0 · Answer 3 · answered Jan 21 '22 at 18:21

I found the issue,

I was using empty list in gridview builder

    List<int> myList = [];

    GridView.builder(
      gridDelegate: SliverGridDelegateWithFixedCrossAxisCount(
        crossAxisSpacing: Dimensions.PADDING_SIZE_LARGE,
        mainAxisSpacing: ResponsiveHelper.isDesktop(context)
            ? Dimensions.PADDING_SIZE_LARGE
            : 0.01,
        childAspectRatio:
            ResponsiveHelper.isDesktop(context) ? 4 : 4,
        crossAxisCount:
            ResponsiveHelper.isMobile(context) ? 1 : 2,
      ),
      physics: BouncingScrollPhysics(),
      shrinkWrap: true,
      itemCount: myList.length,
      itemBuilder: (context, index) {
        return Text("");
      },
    )

myList was not having any values

ScrollExtent is negative in flutter

3 Answers3

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