Flutter Tutorial: List View and List View Builder

Introduction

• Today's focus: List View and List View Builder in Flutter.
• Contexts for using each widget.

Basic Structure

• Start with a blank scaffold.
• Create a column to hold widgets.
• Introduce a basic container with height 200 and a color.

Column Overflow Error

• Problem: Columns can lead to overflow errors when they become full.
• Solution: Use a List View as it is scrollable.
  • Default behavior: scrollable.
  • Can set physics to neverScrollable if needed.

Coding Best Practices

• Encapsulation: Create separate file for reusable components.
  • Example: Create my_square widget in square.dart file.
  • Reduces code repetition for clarity.

List View Basics

• Basic List View: Suitable when you know the number of items.
• Dynamic Lists: Use List View Builder for unknown item counts.
  • Example: Instagram feed (dynamic posts).

Example Implementation

1. Create a list called posts with strings: post 1, post 2, post 3, etc.
2. Use ListView.builder to build dynamically based on posts length.
3. Specify itemCount as posts.length.
4. Pass a string to my_square for display.

Object-Oriented Programming

• Philosophy: Encapsulation and reusability of code (OOP principles).

Instagram UI Layout

Structure

• Use Column to wrap ListView for stories and posts.
• Handle potential layout errors (e.g., render box not laid out).

Solutions

• Fixed Height: Wrap ListView in a container with specific height.
• Expanded Widget: Automatically fills available space.

Stories Implementation

• Create a horizontal scrolling ListView for stories.
  • Set scrollDirection to horizontal.
  • Encapsulate story circles in a separate widget.
• Use item count from a stories list.

Flexibility in Layout

• Set the first ListView (for stories) to a fixed height.
• Allow the second ListView (for posts) to expand and fill the rest of the screen.

Conclusion

• List Views are an extension of Rows and Columns but enable scrolling.
• When to use List View vs. List View Builder.
• Reference to full Instagram UI video for further learning.