development/flutter
development/flutter
1
0
Fork 0
mirror of https://github.com/flutter/flutter synced 2024-08-24 18:36:03 +00:00
Code Issues Packages Projects Releases Wiki Activity

"System back gesture" explanation (#142254)

Browse source 
Improve docs around PopScope and its interaction with back gestures on Android and iOS.
This commit is contained in:
Justin McCandless 2024-01-31 10:46:52 -08:00 committed by GitHub
parent 1d48b60d48
commit 9c2c487e02
No known key found for this signature in database
GPG key ID: B5690EEEBB952194
1 changed files with 17 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

25
packages/flutter/lib/src/widgets/pop_scope.dart
View file

@ -8,22 +8,31 @@ import 'framework.dart';
import 'navigator.dart';
import 'routes.dart';
/// Manages system back gestures.
/// Manages back navigation gestures.
///
/// The [canPop] parameter can be used to disable system back gestures. Defaults
/// to true, meaning that back gestures happen as usual.
/// The [canPop] parameter disables back gestures when set to `false`.
///
/// The [onPopInvoked] parameter reports when system back gestures occur,
/// regardless of whether or not they were successful.
/// The [onPopInvoked] parameter reports when pop navigation was attempted, and
/// `didPop` indicates whether or not the navigation was successful.
///
/// Android has a system back gesture that is a swipe inward from near the edge
/// of the screen. It is recognized by Android before being passed to Flutter.
/// iOS has a similar gesture that is recognized in Flutter by
/// [CupertinoRouteTransitionMixin], not by iOS, and is therefore not a system
/// back gesture.
///
/// If [canPop] is false, then a system back gesture will not pop the route off
/// of the enclosing [Navigator]. [onPopInvoked] will still be called, and
/// `didPop` will be `false`.
/// `didPop` will be `false`. On iOS when using [CupertinoRouteTransitionMixin]
/// with [canPop] set to false, no gesture will be detected at all, so
/// [onPopInvoked] will not be called. Programmatically attempting pop
/// navigation will also result in a call to [onPopInvoked], with `didPop`
/// indicating success or failure.
///
/// If [canPop] is true, then a system back gesture will cause the enclosing
/// [Navigator] to receive a pop as usual. [onPopInvoked] will be called with
/// `didPop` as `true`, unless the pop failed for reasons unrelated to
/// [PopScope], in which case it will be `false`.
/// `didPop` as true, unless the pop failed for reasons unrelated to
/// [PopScope], in which case it will be false.
///
/// {@tool dartpad}
/// This sample demonstrates showing a confirmation dialog before navigating