When do you use ListView.builder instead of building a whole list?

Short answer

A builder creates children on demand, reducing memory and initial work for large or unbounded lists.

Explanation

Use itemBuilder and itemCount with stable keys when needed, and avoid loading all items into a Column or ListView children at once. Do not use a lazy builder if the list is small and fixed with no measured problem.

Common mistakes

• Performing network or parsing inside itemBuilder on every build.
• Using the index as identity for items that can be reordered.

Follow-up questions

• How do you show loading, success, and error for a network request?

Sources

• Flutter cookbook — Place items on demand