[muhammadkamel]

This is the framework/services-only split of #185140, per Piinks' decoupling guidance and the Material/Cupertino freeze in this repository (#188444).

On some Android 14+ devices, the platform sends swipeEdge: 2 (BackEvent.EDGE_NONE) for button-triggered predictive back events. PredictiveBackEvent.fromMap previously indexed SwipeEdge.values[2], which threw a RangeError because the enum only has left and right.

This PR:

• Maps platform swipeEdge values explicitly (0 → left, 1 → right, 2 and unknown → left) so fromMap never throws
• Leaves SwipeEdge unchanged (no new none value), because adding an enum case would require an exhaustive-switch update in frozen Material code
• Continues to treat button events via isButtonEvent (touchOffset == null or Offset.zero with zero progress), which matches the crash payload from the issue

Material widget tests and transition behavior for EDGE_NONE belong in material_ui in flutter/packages. A dedicated SwipeEdge.none value can be added later if Material is no longer frozen here, or ported with that follow-up.

Fixes #186168

Pre-launch Checklist

• I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
• I read the [AI contribution guidelines] and understand my responsibilities, or I am not using AI tools.
• I read the [Tree Hygiene] wiki page, which explains my responsibilities.
• I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement].
• I signed the [CLA].
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is [test-exempt].
• I followed the [breaking change policy] and added [Data Driven Fixes] where supported.
• All existing and new tests are passing.

[gemini-code-assist]

Code Review

This pull request introduces a new SwipeEdge.none enum value to represent button-triggered back events (corresponding to Android's BackEvent.EDGE_NONE). It updates PredictiveBackEvent parsing, isButtonEvent detection, and page transitions to handle this new state, and adds comprehensive unit tests. Feedback suggests explicitly casting map['swipeEdge'] to int and asserting it is non-null during deserialization to maintain type safety and prevent silently ignoring malformed values.

[gemini-code-assist]

To maintain type safety and consistency with how other fields (like progress and touchOffset) are extracted from the map, we should explicitly cast map['swipeEdge'] to int and assert that it is non-null. This prevents silently ignoring null or malformed values, which would otherwise be incorrectly treated as SwipeEdge.none and could mask integration bugs.

Suggested change

	swipeEdge: switch (map['swipeEdge']) {
	0 => SwipeEdge.left,
	1 => SwipeEdge.right,
	2 || _ => SwipeEdge.none,
	},
	swipeEdge: switch (map['swipeEdge']! as int) {
	0 => SwipeEdge.left,
	1 => SwipeEdge.right,
	_ => SwipeEdge.none,
	},

[github-actions]

This pull request contains changes to Material or Cupertino, which are currently frozen in this repository.

Changes should be made in material_ui and/or cupertino_ui in the flutter/packages repository.

Please refer to #188444 for instructions.