Page transition builders reorganization

CupertinoPageTransitionsBuilder has been relocated from package:flutter/material.dart to package:flutter/cupertino.dart.

Flutter provides several page transition builders that control how routes animate when navigating between pages. These builders are used with PageTransitionsTheme to customize transitions per platform.

The available page transition builders are:

Previously, CupertinoPageTransitionsBuilder was defined in the Material library alongside the other builders. However, this class is semantically a Cupertino component—its implementation uses Cupertino transition mixins and provides iOS-style navigation animations.

This move improves code organization and allows Cupertino apps to use this builder without depending on the Material library.

If you use CupertinoPageTransitionsBuilder and only import package:flutter/material.dart, add an import for package:flutter/cupertino.dart.

Code before migration:

import 'package:flutter/material.dart';
​
final pageTransitionsTheme = PageTransitionsTheme(
  builders: {
    TargetPlatform.android: ZoomPageTransitionsBuilder(),
    TargetPlatform.iOS: CupertinoPageTransitionsBuilder(),
  },
);

Code after migration:

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';
​
final pageTransitionsTheme = PageTransitionsTheme(
  builders: {
    TargetPlatform.android: ZoomPageTransitionsBuilder(),
    TargetPlatform.iOS: CupertinoPageTransitionsBuilder(),
  },
);

If your app already imports both packages, no changes are needed.

Landed in version: Not yet released
In stable release: Not yet released

Relevant PRs:

• Decouple CupertinoPageTransitionsBuilder from Material