Tab navigation in Flutter - UI Render Trace

Component - Tab navigation

This UI component shows how to switch between different pages using tabs at the bottom of the screen. Each tab displays a different content area when selected, making it easy to organize app sections.

Widget Tree

Scaffold
├── AppBar
├── body: TabBarView
│   └── children: [HomePage, SearchPage, ProfilePage]
└── bottomNavigationBar: TabBar

The Scaffold provides the basic app layout with a top AppBar. The body contains a TabBarView that shows the content for the selected tab. The bottomNavigationBar holds the TabBar with three tabs: Home, Search, and Profile.

Render Trace - 3 Steps

Step 1: Scaffold

Step 2: TabBar

Step 3: TabBarView

State Change - Re-render

Trigger:User taps on the 'Search' tab in the bottom TabBar.

Before

Selected tab is 'Home', so HomePage content is visible.

→

After

Selected tab changes to 'Search', so SearchPage content is visible.

Re-renders:The TabBarView updates to show SearchPage. The TabBar updates to highlight the 'Search' tab.

UI Quiz - 3 Questions

What happens when the user taps a different tab in the TabBar?

A The AppBar title changes automatically.

B The app closes and restarts.

C The content in the TabBarView changes to match the selected tab.

D Nothing happens; tabs are not interactive.

Key Insight

Tab navigation helps users switch between different app sections quickly. Using TabBar and TabBarView together keeps the UI organized and responsive. Always place TabBar in the bottomNavigationBar for easy access and use TabBarView to show the matching content.