如何在 Flutter 中显示对话框而不在 HookWidget 中显示构建上下文

问题描述

如何在下面给出的示例代码中显示没有 Buildcontext 的 HookWidget，该代码包含在扩展 Undefined name 'context'. 的类中？

目前，我收到了 flutter_hooks: ^0.10.0 hooks_riverpod: ^0.3.0

我正在使用以下包来管理我的应用程序：

class HomeScreen extends HookWidget {
  static String routeName = "/home";

  PageController _pageController = PageController(initialPage: 1);

  dynamic balanceAvailable = 0.0;
  List<TransactionModel> transactionList = [];

  _onRefresh(DragEndDetails details) async {
    showDialog(
        context: context,builder: (BuildContext context) {
          return Center(
            child: SizedBox(
              height: MediaQuery.of(context).size.height / 4,width: MediaQuery.of(context).size.width / 2,child: CircularProgressIndicator(
                valueColor: new AlwaysStoppedAnimation<Color>(Colors.blue),),);
        });
    await Future.delayed(const Duration(seconds: 2));

    Navigator.pop(context);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: GestureDetector(
        onVerticalDragEnd: _onRefresh,child: PageView(
          controller: _pageController,children: [
            MenuScreen(),HomeBody(
              value: balanceAvailable,TransactionScreen(
              transactionList: transactionList,value: balanceAvailable,],);
  }
}

示例代码：

Sub load_form(c As Control,Optional parent_id As Integer = 0)
    i = i + 1
    Dim frmid As Integer
    If Request("formid") Is Nothing Then
        frmid = 1
    Else
        frmid = Request("formid")
    End If


    Dim dt As DataTable
    Dim sql As String = ""
    If parent_id = 0 Then
        sql = "SELECT * from form_fields where form_id=" & frmid & " order by parentid,order_number"
        dt = GetData(sql)
    Else
        sql = "SELECT * from form_fields where form_id=" & frmid & " and parentid=" & parent_id & "  order by parentid,order_number"
        dt = GetData(sql)
    End If

    If dt.Rows.Count > 0 Then
        For Each row As DataRow In dt.Rows
            ' MsgBox(sql)
            Dim p As New Panel()
            If row(2).ToString.Trim(" ") = "panel" Then
                '  MsgBox(dt.Rows(0)(0))
                Dim pnl As New Panel()
                pnl.ID = "pnl" & row(0)
                pnl.GroupingText = row(9)
                p = pnl
                load_form(p,row(0))
            End If
            If row(2).ToString.Trim() = "textbox" Then
                Dim t As New TextBox With {
                    .CssClass = "form-control"}
                t.Attributes.Add("showto","true")
                t.Attributes.Add("dbdata","true")
                t.Attributes.Add("placeholder","Enter O2 Level...")
                t.ID = "Txt" & i
                p.Controls.Add(t)
            End If
            If row(2).ToString.Trim() = "checkbox" Then
                Dim cb As New CheckBox With {
                    .CssClass = "cb form-control"}
                cb.Attributes.Add("showto","All")
                cb.Attributes.Add("dbdata","true")
                cb.Attributes.Add("title",row("title").ToString.Trim())
                cb.Attributes.Add("altValue",row("altvalue").ToString.Trim())
                cb.Text = row(7).ToString.Trim()
                cb.ID = "cb" & i
                p.Controls.Add(cb)
            End If
            c.Controls.Add(p)
   
        Next
   End If
End Sub

解决方法

您可以在下面复制粘贴运行完整代码
您可以将 context 传递给 _onRefresh
第 1 步：_onRefresh(DragEndDetails details,BuildContext context)
第 2 步：onVerticalDragEnd: (details) => {_onRefresh(details,context)},

工作演示

完整代码

import 'package:flutter/material.dart';
import 'package:flutter_hooks/flutter_hooks.dart';

class TransactionModel {}

class HomeScreen extends HookWidget {
  static String routeName = "/home";

  PageController _pageController = PageController(initialPage: 1);

  dynamic balanceAvailable = 0.0;
  List<TransactionModel> transactionList = [];

  _onRefresh(DragEndDetails details,BuildContext context) async {
    showDialog(
        context: context,builder: (BuildContext context) {
          return Center(
            child: SizedBox(
              height: MediaQuery.of(context).size.height / 4,width: MediaQuery.of(context).size.width / 2,child: CircularProgressIndicator(
                valueColor: new AlwaysStoppedAnimation<Color>(Colors.blue),),);
        });
    await Future.delayed(const Duration(seconds: 2));

    Navigator.pop(context);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: GestureDetector(
        onVerticalDragEnd: (details) => {_onRefresh(details,child: PageView(
          controller: _pageController,children: [
            MenuScreen(),HomeBody(),TransactionScreen(),],);
  }
}

class MenuScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("MenuScreen"),body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,children: <Widget>[
              Text(
                'MenuScreen',));
  }
}

class HomeBody extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("HomeBody"),children: <Widget>[
              Text(
                'HomeBody',));
  }
}

class TransactionScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
        appBar: AppBar(
          title: Text("TransactionScreen"),children: <Widget>[
              Text(
                'TransactionScreen',));
  }
}

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',theme: ThemeData(
        primarySwatch: Colors.blue,home: HomeScreen(),);
  }
}

,

您是否尝试过钩子的 useContext() 例程？