App navigation

App Flow

The app follows this general flow:

Launch → Scanner Screen → [Connect via BLE/USB/TCP] → Channels Screen

After connecting, the three main screens (Contacts, Channels, Map) are accessible via a persistent bottom navigation bar called the QuickSwitchBar.

Quick Switch Bar

The QuickSwitchBar is a Material 3 NavigationBar with a frosted-glass visual treatment (blur backdrop, transparent theme, rounded corners). It appears at the bottom of all three main screens.

Index	Icon	Label	Screen
0	People	Contacts	ContactsScreen
1	Tag	Channels	ChannelsScreen
2	Map	Map	MapScreen

Tapping a tab replaces the current screen with a subtle fade + slight horizontal nudge transition (220ms forward, 200ms reverse). The back button is suppressed on all three main screens — navigation between them is flat, not stacked. All icons use outline variants (people_outline, tag, map_outlined) following Material 3 conventions.

Disconnection

• The disconnect button (available in the overflow menu of each main screen) shows a confirmation dialog before disconnecting
• If the device disconnects unexpectedly, the app automatically navigates back to the Scanner screen (fires after the current frame completes via a post-frame callback)
• This auto-navigation behavior (DisconnectNavigationMixin) is shared across all main screens

Theme and Locale

• Theme mode is user-configurable in App Settings (System / Light / Dark) — not locked to system
• Language can be overridden to one of 18 supported languages, or follow the system locale
• On web, if a non-Chromium browser is detected, the app shows a ChromeRequiredScreen instead of the Scanner (Web Bluetooth requires Chromium)

Full Navigation Graph

ScannerScreen (root, always on stack)
  ├─ [BLE connect] → push → ChannelsScreen
  ├─ [TCP icon button] → push → TcpScreen
  │     └─ [TCP connected] → pushReplacement → ChannelsScreen
  └─ [USB icon button] → push → UsbScreen
        └─ [USB connected] → pushReplacement → ChannelsScreen

ContactsScreen (selected=0)
  ├─ [quick-switch 1] → pushReplacement → ChannelsScreen
  ├─ [quick-switch 2] → pushReplacement → MapScreen
  ├─ [tap contact] → push → ChatScreen
  ├─ [overflow > Settings] → push → SettingsScreen
  └─ [overflow > Discovered] → push → DiscoveryScreen

ChannelsScreen (selected=1)
  ├─ [quick-switch 0] → pushReplacement → ContactsScreen
  ├─ [quick-switch 2] → pushReplacement → MapScreen
  ├─ [tap channel] → push → ChannelChatScreen
  └─ [overflow > Settings] → push → SettingsScreen

MapScreen (selected=2)
  ├─ [quick-switch 0] → pushReplacement → ContactsScreen
  ├─ [quick-switch 1] → pushReplacement → ChannelsScreen
  ├─ [radar menu item] → enters in-map path trace mode (push → PathTraceMapScreen after path is built)
  ├─ [terrain menu item] → push → LineOfSightMapScreen
  └─ [long-press] → share marker sheet

Settings (push from any main screen)
  └─ [App Settings] → push → AppSettingsScreen
        └─ [Offline Map Cache] → push → MapCacheScreen

Any disconnection from any screen triggers popUntil(route.isFirst), returning to the Scanner.