Vertical viewport was given unbounded height

Why This Happens

In Flutter, ListView has infinite height by default and Column gives its children unbounded vertical space. Placing a ListView directly inside a Column without constraints causes this error because both try to be infinitely tall. Wrap the ListView in Expanded or give it a fixed height.

The Problem

Column(
  children: [
    Text('Header'),
    ListView(
      children: items.map((e) => ListTile(title: Text(e))).toList(),
    ),
  ],
)

The Fix

Column(
  children: [
    Text('Header'),
    Expanded(
      child: ListView(
        children: items.map((e) => ListTile(title: Text(e))).toList(),
      ),
    ),
  ],
)

Step-by-Step Fix

1. 1

   Identify the error

   Look at the error message: Vertical viewport was given unbounded height. This means a scrollable widget has no height constraint.

2. 2

   Find the cause

   Check if a ListView, GridView, or CustomScrollView is placed inside a Column, Row, or another unconstrained parent.

3. 3

   Apply the fix

   Wrap the scrollable widget in Expanded or SizedBox to provide a bounded height, or set shrinkWrap: true on the ListView.