flutter - 在 flutter 中重新启动(关闭并再次打开)后对话框状态不会改变

Question

我在一个 StatelessWidget 中定义了一个按钮(这将具有 bloc 创建逻辑并使用 bloc 提供程序注入(inject)，)，单击该按钮时我会显示一个对话框并将 bloc 实例传递给它，如代码所示.

//EsignBloc is defined here in parent statelessWidget. Defined i.e. creating the bloc instance and passing through the BlocProvider. Removed the code for simplicity


//This listener will be called when Button defined inside statelessWidget will be clicked. this is responsible for showing the dialog.
void _onClickHere(
    BuildContext context,
  ) {
    final dialog = Dialog(
      shape: RoundedRectangleBorder(
        borderRadius: BorderRadius.circular(AppConstants.borderRadius),
      ),
      elevation: 0.0,
      backgroundColor: Colors.transparent,
      child: _GetSignUsingOtpView(),
    );

    showDialog(
      context: context,
      builder: (_) => BlocProvider<EsignBloc>(
        create: (_) => BlocProvider.of<EsignBloc>(context), // passing already created bloc to dialog
        child: WillPopScope(
          onWillPop: () => Future.value(false),
          child: dialog,
        ),
      ),
      barrierDismissible: false,
    );
  }

粘贴 _GetSignUsingOtpView() 的一些代码

class _GetSignUsingOtpView extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BlocBuilder<EsignBloc, EsignState>(builder: (context, state) {
      return Container(
        decoration: BoxDecoration(
          color: AppColor.white,
          borderRadius: BorderRadius.circular(
            AppConstants.borderRadius,
          ),
        ),
        child: Column(
              mainAxisSize: MainAxisSize.min,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: [
                Align(
                  alignment: Alignment.centerRight,
                  child: InkWell(
                    onTap: () => _closeDialog(context),
                    child: Padding(
                      padding: const EdgeInsets.only(top: 8.0, right: 8),
                      child: Icon(
                        Icons.cancel,
                        color: AppColor.primaryDark,
                        size: SizeConfig.safeBlockVertical * 2,
                      ),
                    ),
                  ),
                ),
                Padding(
                  padding: const EdgeInsets.all(24),
                  child: Column(
                    mainAxisSize: MainAxisSize.min,
                    crossAxisAlignment: CrossAxisAlignment.stretch,
                    children: [
                      PrimaryText(text: state.otp), // data does not change after closing and opeing dialog again 
                      PrimaryText(text: state.remainingTime), // data does not change after closing and opeing dialog again 
                    ],
                  ),
                ),
              ],
            ),
      );
    });
  }

  void _closeDialog(BuildContext context) {
    Navigator.pop(context);
  }
}

我面临的问题是每当对话框在关闭后再次打开时，它不会显示来自 Bloc 的最新数据。该对话框仅显示该 Bloc 中以前的任何数据。有人可以指出我在哪里犯了错误吗？

Answer 1

你的对话框没有显示新数据的原因是你正在创建一个新的 bloc 实例。即使你说你不是。

BlocProvider<EsignBloc>(
  create: (_) => BlocProvider.of<EsignBloc>(context), // passing already created bloc to dialog
  child: ...

In some cases, BlocProvider can be used to provide an existing cubit to a new portion of the widget tree. This will be most commonly used when an existing cubit needs to be made available to a new route. In this case, BlocProvider will not automatically close the cubit since it did not create it.

要不创建新实例，您需要使用BlocProvider.value。您可以阅读更多相关信息 here

BlocProvider.value(
  value: BlocProvider.of<EsignBloc>(context),
  child: ...,
);

这将使用先前的实例并将其提供给子小部件，而不是创建新实例，并且在使用完后不会关闭 bloc。这对于对话框和导航很方便。