flutter - How to show bloc state in AlertDialog

I have very simple app which use switch and bloc state management. Switch state management work, but I would like to show state of switch to user via AlertDialog.

Here is switch widget:

  @override
  Widget build(BuildContext context) {
    return BlocProvider(
      create: (_) => SwitchCubit(),
      child: BlocBuilder<SwitchCubit, bool>(
        builder: (context, state) {
          return Switch(
            value: state,
            activeColor: Colors.green,
            onChanged: (bool value) {
              // This is called when the user toggles the switch.
              BlocProvider.of<SwitchCubit>(context).toggle();
            },
          );
        },
      ),
    );
  }

and here is way I'm trying to show state of switch to user (true or false).

appBar: AppBar(
  title: const Text('Switch bloc test'),
  actions: [
    IconButton(
      icon: const Icon(Icons.info),
      tooltip: 'Switch bloc test',
      onPressed: () {
        showDialog(
          context: context,
          builder: (context) {
            return Material(
              child: BlocBuilder<SwitchCubit, bool>(
                builder: (context, state) => AlertDialog(
                  content: Text(state.toString()),
                ),
              ),
            );
          },
        );
      },
    ),
  ],
),

How should I continue and avoid getting this ?

Source code of project: https://github.com/Kalyxt/switchbloc_flutter

You have to provide the Bloc/Cubit to the AlertDialog. That's because it is a different BuildContext in the dialog.

Wrap the Material widget in the showDialog method with a BlocProvider and provide the SwitchCubit there.

Kind of the same solution as I described here:

https://stackoverflow.com/questions/75774451/handle-blocprovider-with-modal-bottom-sheet/75775051#75775051

Edit:

1. Don't create a new SwitchCubit. Provide an already existing one.

2. Make sure that the existing SwitchCubit is created above this in the widget tree.

3. Rename the inner build context so that the correct BuildContext is used when providing the Bloc/Cubit to the dialog.

    showDialog(
      context: context,
      builder: (innerContext) {
        return BlocProvider.value(
          value: context.watch<SwitchCubit>(),
          child: Material(
            child: BlocBuilder<SwitchCubit, bool>(
              builder: (context, state) => AlertDialog(
                content: Text(state.toString()),
              ),
            ),
          ),
        );
      },
    );
   

Note: If you get the same fault now, then you haven't done bullet 2) above.

Try to add an extra builder, to get a new context with the created SwitchCubit

    return BlocProvider(
      create: (_) => SwitchCubit(),
      child: Builder(
        builder: (context) {
          return BlocBuilder<SwitchCubit, bool>(
            builder: (context, state) {
              return Switch(
                value: state,
                activeColor: Colors.green,
                onChanged: (bool value) {
                  // This is called when the user toggles the switch.
                  BlocProvider.of<SwitchCubit>(context).toggle();
                },
              );
            },
          );
        },
      ),
    );
    ```

</details>



# 答案3
**得分**: 0

You used bloc provider in different route, so that state can't find provider, use provider in main then all widget in the tree can access it.

<details>
<summary>英文:</summary>

You used bloc provider in different route, so that state can&#39;t find provider, use provider in main then all widget in the tree can access it

</details>