TheNavigator page APIs are refactored so that they can integrate with Flutter's other pop mechanisms.

TheonPopPage property was added for cleaning up pages after a page is about to be popped. To veto pop, you'd returnfalse in the callback. This did not work well with other popping mechanisms in the framework, such asPopScope and iOS back gestures.

To integrate the framework's pop mechanisms together, the page APIs needed to be refactored.

TheonDidRemovePage property replaces theonPopPage property. You can no longer veto a pop in theonDidRemovePage property. Instead, you are only responsible for updating thepages.

The veto mechanism is now managed with thePage.canPop andPage.onPopInvoked properties. These function similar to how you use thePopScope widget.

Code before migration:

import'package:flutter/material.dart';​finalMaterialPage<void>page1=MaterialPage<void>(child:Placeholder());finalMaterialPage<void>page2=MaterialPage<void>(child:Placeholder());finalMaterialPage<void>page3=MaterialPage<void>(child:Placeholder());​voidmain(){finalList<Page<void>>pages=<Page<void>>[page1,page2,page3];runApp(MaterialApp(home:Navigator(pages:pages,onPopPage:(Route<Object?>route,Object?result){if(route.settings==page2){returnfalse;}if(route.didPop){pages.remove(route.settings);returntrue;}returnfalse;},),),);}

Code after migration:

import'package:flutter/material.dart';​finalMaterialPage<void>page1=MaterialPage<void>(child:Placeholder());finalMaterialPage<void>page2=MaterialPage<void>(canPop:false,child:Placeholder());finalMaterialPage<void>page3=MaterialPage<void>(child:Placeholder());​voidmain(){finalList<Page<void>>pages=<Page<void>>[page1,page2,page3];runApp(MaterialApp(home:Navigator(pages:pages,onDidRemovePage:(Page<Object?>page){pages.remove(page);},),),);}

Landed in version: 3.22.0-32.0.pre
In stable release: 3.24.0

API documentation:

• Navigator
• PopScope

Relevant issue:

• Issue 137458

Relevant PR:

• Refactors page API