Tag: dart

For a long list, never use shrinkWrap. Use Expanded when the list is the only scrollable, and slivers (CustomScrollView) when it shares a scroll with other sections. Here is why, with a build-count benchmark.

Riverpod 3.0 wraps errors thrown while reading a provider in a ProviderException. Catch that type and read e.exception to get your original error back, or use AsyncValue.error which is unwrapped.

Dot shorthands went stable in Dart 3.12.2. Write .center or .new and let the compiler infer the type from context. Here is how they work across enums, static members, and constructors.

Move the color inside the decoration: use decoration: BoxDecoration(color: ...) instead of passing both color and decoration to the same Container.

This error means an Expanded or Flexible is not a direct child of a Row, Column, or Flex. Move it directly under the flex widget, or drop Expanded if the parent is not a flex.

The slivers list of a CustomScrollView only accepts slivers. Wrap box widgets in SliverToBoxAdapter, or swap ListView/Padding/Column for SliverList and SliverPadding.

In a Notifier, resolve dependencies before the await, then guard the state write with if (!ref.mounted) return. This is the Riverpod 3.0 replacement for the old onDispose mixin, and it stops UnmountedRefException when a provider is disposed mid-await. Tested on flutter_riverpod 3.x, Flutter 3.44, Dart 3.x.

Put a list and a grid in a single continuous scroll without nested scrollables. Use CustomScrollView with SliverList and SliverGrid, and skip the shrinkWrap trap that quietly kills performance.

Why a ListView in a Column throws 'Vertical viewport was given unbounded height', and the four fixes (Expanded, Flexible, shrinkWrap, SizedBox) with the performance trade-offs that decide which one you want.

This crash means you read a late field before anything assigned it. Initialize it synchronously in initState, or stop using late and model the async value as nullable state.