dual_screen_hinge #

iPhone Duo-first foldable support for Flutter: continuous hinge angles, posture, reserved regions, screen role, and Android display modes.

Use it alongside MediaQuery #

On Android, prefer MediaQuery.displayFeatures for adaptive layout and the basic opened/half-opened state Flutter already exposes. Use this plugin when you need continuous angles for animation, richer fold/hinge metadata, supported postures, rear/dual-screen display sessions, or iOS support.

Install #

dependencies:
  dual_screen_hinge: ^0.2.1

Requires Flutter 3.38+, Dart 3.10+, Android API 21+, or iOS 13+. iPhone Duo hinge telemetry requires a UIKit SDK that declares UIHingeInteraction. Reserved-region geometry requires an SDK that declares reservedRegions. CocoaPods and Swift Package Manager detect these APIs automatically; Xcode 27.0 SDKs without them keep the safe, unsupported fallback. No Podfile workaround is needed. Runtime support still depends on the iOS version and hardware.

Read state and animate #

final subscription = DualScreenHinge.instance.events.listen((state) {
  print('${state.posture} ${state.hingeAngle}°');
});

StreamBuilder<double>(
  stream: DualScreenHinge.instance.hingeAngleEvents,
  builder: (context, snapshot) {
    final angle = snapshot.data ?? 180;
    return Transform.rotate(
      angle: (180 - angle) * math.pi / 180,
      child: const MyFoldEffect(),
    );
  },
);

The native event stream is shared by all Dart listeners, sends a snapshot on listen, deduplicates state, and coalesces sensor updates to approximately one per display frame.

Read regions for custom layout #

final state = await DualScreenHinge.instance.currentState();
final activeRegionBounds = state.reservedRegions
    .where((region) => region.isActive)
    .map((region) => region.bounds)
    .toList(growable: false);

On iOS 27.1, reservedRegions contains the folding region (division) and camera regions (occlusion) in Flutter logical coordinates. Inactive regions are included so a grid can, for example, prefer an even number of columns before the fold becomes active. Active division regions are also exposed in displayFeatures for cross-platform layout code.

Use MediaQuery.sizeOf(context), MediaQuery.paddingOf(context), and flexible constraints for the overall layout. Use reserved regions only to displace important custom-positioned elements using activeRegionBounds; don't drive layout from the hinge angle or fixed iPhone Duo dimensions. See Apple's iPhone Duo HIG.

Display modes (Android) #

final capabilities = await DualScreenHinge.instance.capabilities();

if (capabilities.rearDisplay) {
  await DualScreenHinge.instance.startRearDisplay();
}

if (capabilities.dualScreenPresentation) {
  await DualScreenHinge.instance.startDualScreen(
    entrypoint: 'dualScreenSecondaryMain',
    arguments: ['initial payload'],
  );
}

@pragma('vm:entry-point')
void dualScreenSecondaryMain(List<String> arguments) {
  runApp(SecondaryDisplayApp(arguments: arguments));
}

Only one display session can be pending or active. V1 deliberately supports startup arguments, not a cross-engine message bus. On iOS, display-mode methods return DualScreenException(code: 'unsupported') because there is no equivalent app-controlled public session API.

Platform behavior #

No device allowlist, OEM reflection, or private API is used. Unsupported data is nullable or reported through runtime capabilities.

Flutter-rendered toolbars don't automatically become UIKit's iPhone Duo vertical bars. Keep controls inside each independent safe-area edge, preserve their relative order across sizes, and let decorative backgrounds extend edge-to-edge separately from interactive content.

Documentation #

See the documentation site, the complete wire contract, device matrix, the deployment guide, and testing guide. The example/ app includes a live fold animation and compares plugin output with MediaQuery.displayFeatures.

License #

MIT. See LICENSE.