如何将 CupertinoApp 包装在 Localizations 小部件中，以便我可以在其中使用 Material 小部件？

Question

我正在使用 CupertinoApp 小部件来包装我的应用，同时尝试在其中使用 Material TextFormField 小部件。

当我触发文本选择模式（双击文本字段）时，我收到以下错误（因为它试图打开需要材质本地化的覆盖小部件）：

错误信息

未找到 MaterialLocalization。 OverlayEntry 小部件需要由 Localizations 小部件祖先提供的 MaterialLocalizations。

本地化用于生成材料库使用的许多不同的消息、标签和缩写。

要引入 MaterialLocalizations，可以在应用程序的根目录中使用 MaterialApp 来：自动包含它们，或者添加一个带有 MaterialLocalizations 委托的 Localization 小部件。

---

问题是我不能使用 MaterialApp，因为我需要使用 Cupertino 风格的导航（CupertinoTabBar/CupertinoTabView 内的嵌套导航器），所以我需要使用本地化小部件方法。

但是下面的代码并不能解决问题：

void main() {
  runApp(
    Localizations(
      child: CupertinoApp(
        debugShowCheckedModeBanner: false,
        home: App(), // <-- Main Screen, a Cupertino Tab Scaffold with 3 CupertinoTabViews
      ),
      locale: Locale('en', 'US'),
      delegates: <LocalizationsDelegate>[

        // I assumed these were sufficient, but the runtime exception still persist.
        DefaultMaterialLocalizations.delegate,
        DefaultCupertinoLocalizations.delegate,
        DefaultWidgetsLocalizations.delegate,
      ],
    ),
  );
}

那么我的问题是，这样做的正确方法是什么，是否不能在 CupertinoApp 中使用 Material 小部件？

I/flutter ( 7631): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter ( 7631): The following assertion was thrown building
I/flutter ( 7631): _OverlayEntry-[LabeledGlobalKey<_OverlayEntryState>#1e5c6](dirty, dependencies:
I/flutter ( 7631): [_LocalizationsScope-[GlobalKey#d1cfa]], state: _OverlayEntryState#ba2a3):
I/flutter ( 7631): No MaterialLocalizations found.
I/flutter ( 7631): _OverlayEntry widgets require MaterialLocalizations to be provided by a Localizations widget
I/flutter ( 7631): ancestor.
I/flutter ( 7631): Localizations are used to generate many different messages, labels,and abbreviations which are used
I/flutter ( 7631): by the material library. 
I/flutter ( 7631): To introduce a MaterialLocalizations, either use a  MaterialApp at the root of your application to
I/flutter ( 7631): include them automatically, or add a Localization widget with a MaterialLocalizations delegate.
I/flutter ( 7631): The specific widget that could not find a MaterialLocalizations ancestor was:
I/flutter ( 7631):   _OverlayEntry-[LabeledGlobalKey<_OverlayEntryState>#1e5c6]
I/flutter ( 7631): The ancestors of this widget were:
I/flutter ( 7631):   Stack(alignment: AlignmentDirectional.topStart, fit: expand, overflow: clip)
I/flutter ( 7631):   _Theatre
I/flutter ( 7631):   Overlay-[LabeledGlobalKey<OverlayState>#362c7]
I/flutter ( 7631):   _FocusScopeMarker
I/flutter ( 7631):   Semantics(container: false, properties: SemanticsProperties, label: null, value: null, hint: null,
I/flutter ( 7631):   hintOverrides: null)
I/flutter ( 7631):   FocusScope
I/flutter ( 7631):   AbsorbPointer(absorbing: false)
I/flutter ( 7631):   Listener(listeners: [down, up, cancel], behavior: deferToChild)
I/flutter ( 7631):   Navigator-[GlobalObjectKey<NavigatorState> _WidgetsAppState#2397a]
I/flutter ( 7631):   DefaultTextStyle(inherit: false, color: Color(0xff000000), family: .SF Pro Text, size: 17.0,
I/flutter ( 7631):   letterSpacing: -0.4, decoration: TextDecoration.none, softWrap: wrapping at box width, overflow:
I/flutter ( 7631):   clip)
I/flutter ( 7631):   Title(color: Color(0xff007aff))
I/flutter ( 7631):   Directionality(textDirection: ltr)
I/flutter ( 7631):   _LocalizationsScope-[GlobalKey#d1cfa]
I/flutter ( 7631):   Semantics(container: false, properties: SemanticsProperties, label: null, value: null, hint: null,
I/flutter ( 7631):   textDirection: ltr, hintOverrides: null)
I/flutter ( 7631):   Localizations(locale: en_US, delegates: [DefaultCupertinoLocalizations.delegate(en_US),
I/flutter ( 7631):   DefaultWidgetsLocalizations.delegate(en_US)])
I/flutter ( 7631):   MediaQuery(MediaQueryData(size: Size(411.4, 683.4), devicePixelRatio: 2.6, textScaleFactor: 1.0,
I/flutter ( 7631):   platformBrightness: Brightness.light, padding: EdgeInsets(0.0, 24.0, 0.0, 0.0), viewInsets:
I/flutter ( 7631):   EdgeInsets.zero, alwaysUse24HourFormat: false, accessibleNavigation: falsedisableAnimations:
I/flutter ( 7631):   falseinvertColors: falseboldText: false))
I/flutter ( 7631):   WidgetsApp-[GlobalObjectKey _CupertinoAppState#5df27]
I/flutter ( 7631):   IconTheme(IconThemeData#33904(color: Color(0xff007aff)))
I/flutter ( 7631):   _InheritedCupertinoTheme
I/flutter ( 7631):   CupertinoTheme
I/flutter ( 7631):   ScrollConfiguration(behavior: _AlwaysCupertinoScrollBehavior)
I/flutter ( 7631):   CupertinoApp
I/flutter ( 7631):   Directionality(textDirection: ltr)
I/flutter ( 7631):   _LocalizationsScope-[GlobalKey#dfb7d]
I/flutter ( 7631):   Semantics(container: false, properties: SemanticsProperties, label: null, value: null, hint: null,
I/flutter ( 7631):   textDirection: ltr, hintOverrides: null)
I/flutter ( 7631):   Localizations(locale: en_US, delegates: [DefaultMaterialLocalizations.delegate(en_US),
I/flutter ( 7631):   DefaultCupertinoLocalizations.delegate(en_US), DefaultWidgetsLocalizations.delegate(en_US)])
I/flutter ( 7631):   _InheritedModel<AppModel>
I/flutter ( 7631):   AnimatedBuilder(animation: Instance of 'AppModel')
I/flutter ( 7631):   ScopedModel<AppModel>
I/flutter ( 7631):   [root]
I/flutter ( 7631): 
I/flutter ( 7631): When the exception was thrown, this was the stack:
I/flutter ( 7631): #0      debugCheckHasMaterialLocalizations.<anonymous closure> (package:flutter/src/material/debug.dart:124:7)
I/flutter ( 7631): #1      debugCheckHasMaterialLocalizations (package:flutter/src/material/debug.dart:127:4)
I/flutter ( 7631): #2      _MaterialTextSelectionControls.buildToolbar (package:flutter/src/material/text_selection.dart:135:12)
// ....

Answer 1

您不应将CupertinoApp 包装成Localization。

CupertinoApp 包括插入其自己的 Localization 小部件，因此您在 CupertinoApp 上方添加的任何内容都会被覆盖。

相反，将您的代表直接传递给localizationsDelegates 或CupertinoApp：

CupertinoApp(
  localizationsDelegates: [
    DefaultMaterialLocalizations.delegate,
    DefaultCupertinoLocalizations.delegate,
    DefaultWidgetsLocalizations.delegate,
  ],
),

Answer 2

只需将 GlobalCupertinoLocalizations.delegate 添加到 GlobalMaterialLocalizations.delegate 的底部

Answer 3

试试这些

localizationsDelegates: <LocalizationsDelegate<dynamic>>[
    GlobalWidgetsLocalizations.delegate,
    GlobalCupertinoLocalizations.delegate,
    GlobalMaterialLocalizations.delegate,
],

完整示例

return MaterialApp(
    title: 'MyAppName',
    debugShowCheckedModeBanner: false,
    home: MyHomeScreen(),
    localizationsDelegates: <LocalizationsDelegate<dynamic>>[
        GlobalWidgetsLocalizations.delegate,
        GlobalCupertinoLocalizations.delegate,
        GlobalMaterialLocalizations.delegate,
    ],
    supportedLocales: <Locale>[
        const Locale('pt', 'BR'),
    ],
  );
}

它也适用于 CupertinoApp