Flutter Textfield长按报错修复:NosuchMethodError: The getter 'pasterButtonLabel' was called on null.

1、问题现象

iOS端在长按Textfield唤起粘贴复制的时候会报错。
如图所示：

33.jpg

2、解决方案

主要原因是Cupertino缺少了对应的非英文版本的支持。

增加代码

import 'package:flutter/cupertino.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/material.dart';
import 'package:flutter_localizations/flutter_localizations.dart';

class ChineseCupertinoLocalizations implements CupertinoLocalizations {
  final materialDelegate = GlobalMaterialLocalizations.delegate;
  final widgetsDelegate = GlobalWidgetsLocalizations.delegate;
  final local = const Locale('zh');

  MaterialLocalizations ml;

  Future init() async {
    ml = await materialDelegate.load(local);
    print(ml.pasteButtonLabel);
  }

  @override
  String get alertDialogLabel => ml.alertDialogLabel;

  @override
  String get anteMeridiemAbbreviation => ml.anteMeridiemAbbreviation;

  @override
  String get copyButtonLabel => ml.copyButtonLabel;

  @override
  String get cutButtonLabel => ml.cutButtonLabel;

  @override
  DatePickerDateOrder get datePickerDateOrder => DatePickerDateOrder.mdy;

  @override
  DatePickerDateTimeOrder get datePickerDateTimeOrder =>
      DatePickerDateTimeOrder.date_time_dayPeriod;

  @override
  String datePickerDayOfMonth(int dayIndex) {
    return dayIndex.toString();
  }

  @override
  String datePickerHour(int hour) {
    return hour.toString().padLeft(2, "0");
  }

  @override
  String datePickerHourSemanticsLabel(int hour) {
    return "$hour" + "时";
  }

  @override
  String datePickerMediumDate(DateTime date) {
    return ml.formatMediumDate(date);
  }

  @override
  String datePickerMinute(int minute) {
    return minute.toString().padLeft(2, '0');
  }

  @override
  String datePickerMinuteSemanticsLabel(int minute) {
    return "$minute" + "分";
  }

  @override
  String datePickerMonth(int monthIndex) {
    return "$monthIndex";
  }

  @override
  String datePickerYear(int yearIndex) {
    return yearIndex.toString();
  }

  @override
  String get pasteButtonLabel => ml.pasteButtonLabel;

  @override
  String get postMeridiemAbbreviation => ml.postMeridiemAbbreviation;

  @override
  String get selectAllButtonLabel => ml.selectAllButtonLabel;

  @override
  String timerPickerHour(int hour) {
    return hour.toString().padLeft(2, "0");
  }

  @override
  String timerPickerHourLabel(int hour) {
    return "$hour".toString().padLeft(2, "0") + "时";
  }

  @override
  String timerPickerMinute(int minute) {
    return minute.toString().padLeft(2, "0");
  }

  @override
  String timerPickerMinuteLabel(int minute) {
    return minute.toString().padLeft(2, "0") + "分";
  }

  @override
  String timerPickerSecond(int second) {
    return second.toString().padLeft(2, "0");
  }

  @override
  String timerPickerSecondLabel(int second) {
    return second.toString().padLeft(2, "0") + "秒";
  }

  static const LocalizationsDelegate delegate =
      _ChineseDelegate();

  static Future load(Locale locale) async {
    var localizaltions = ChineseCupertinoLocalizations();
    await localizaltions.init();
    return SynchronousFuture(localizaltions);
  }
}

class _ChineseDelegate extends LocalizationsDelegate {
  const _ChineseDelegate();

  @override
  bool isSupported(Locale locale) {
    return locale.languageCode == 'zh';
  }

  @override
  Future load(Locale locale) {
    return ChineseCupertinoLocalizations.load(locale);
  }

  @override
  bool shouldReload(LocalizationsDelegate old) {
    return false;
  }
}

在 Application 里配置一下

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(title: 'Flutter Demo Home Page'),
      localizationsDelegates: >[
        ChineseCupertinoLocalizations.delegate, // 自定义的delegate

        DefaultCupertinoLocalizations.delegate, // 目前只包含英文

        // 下面两个是Material widgets的delegate, 包含中文
        GlobalMaterialLocalizations.delegate,
        GlobalWidgetsLocalizations.delegate,
      ],
      supportedLocales: [
        const Locale('en', 'US'), // English
        const Locale('zh', 'Hans'), // China
        const Locale('zh', ''), // China
        // ... other locales the app supports
      ],
    );
  }
}