Theme is not accessible after navigation to next page about flutter-neumorphic

[florent37]

I tried your code and saw the crash. It can be explain by the fact you use Navigator.pushReplacement

The NeumorphicTheme in you project is the direct child of thee MaterialApp

return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Flutter Demo',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: NeumorphicTheme(
usedTheme: UsedTheme.LIGHT,
theme: NeumorphicThemeData(
baseColor: Color(0xFFFFFFFF),
intensity: 0.5,
lightSource: LightSource.topLeft,
depth: 10,
),
darkTheme: NeumorphicThemeData(
baseColor: Color(0xFF3E3E3E),
intensity: 0.5,
lightSource: LightSource.topLeft,
depth: 6,
),
child: MyHomePage()),
);
}

A MaterialApp contains a Navigator Widget, knowing this, if you use PushReplacement, the child of this MaterialApp is "replaced" by your new page.

The NeumorphicTheme cannot be found seearching on your widget tree, because he is not above your widget !

I can send you two solutions :

1. Add a navigator below the NeumorphicTheme :

Complex to add inside a tree, and useless just for this usecase

2. Move the NeumorphicTheme above your MaterialApp (so above the Navigator)

return NeumorphicTheme(
      usedTheme: UsedTheme.LIGHT,
      theme: NeumorphicThemeData(
        baseColor: Color(0xFFFFFFFF),
        intensity: 0.5,
        lightSource: LightSource.topLeft,
        depth: 10,
      ),
      darkTheme: NeumorphicThemeData(
        baseColor: Color(0xFF3E3E3E),
        intensity: 0.5,
        lightSource: LightSource.topLeft,
        depth: 6,
      ),
      child: MaterialApp(
        debugShowCheckedModeBanner: false,
        title: 'Flutter Demo',
        theme: ThemeData(
          primarySwatch: Colors.blue,
        ),
        home: MyHomePage(),
      ),
    );

I tested the 2. And it works perfectly !

[florent37]

https://stackoverflow.com/questions/56413575/inheritedwidget-giving-data-as-null-down-the-widget-tree-flutter