未处理的异常：将对象转换为可编码对象失败：“SendMessage”实例答案

【问题标题】：Unhandled Exception: Converting object to an encodable object failed: Instance of 'SendMessage'未处理的异常：将对象转换为可编码对象失败：“SendMessage”实例
【发布时间】：2021-10-05 02:40:36
【问题描述】：

我在使用来自 TDLib 的 Flutter 端口的 SendMessage 函数时遇到问题，可以在此处找到：https://pub.dev/packages/tdlib。尽管我以类似的方式从该插件执行其他功能，但它们工作得很好，我不完全了解导致此问题的原因。这是我的函数使用示例：

sendMessage() async {
    TdApi.FormattedText messageText = TdApi.FormattedText(text: messageGetter.text,);

    TdApi.MessageSendOptions messageSendOptions = TdApi.MessageSendOptions(disableNotification: false) ;
    
    TdApi.InputMessageText message = TdApi.InputMessageText(text: messageText);

    final result = await context.read<TelegramService>().send(
      TdApi.SendMessage(chatId: contact_id, inputMessageContent: message, options: messageSendOptions),
    );

    print(result);
  }

来自 Android Studio 的堆栈跟踪：

E/flutter (13086): #0      _JsonStringifier.writeObject (dart:convert/json.dart:688:7)
E/flutter (13086): #1      _JsonStringStringifier.printOn (dart:convert/json.dart:877:17)
E/flutter (13086): #2      _JsonStringStringifier.stringify (dart:convert/json.dart:862:5)
E/flutter (13086): #3      JsonEncoder.convert (dart:convert/json.dart:262:30)
E/flutter (13086): #4      JsonCodec.encode (dart:convert/json.dart:172:45)
E/flutter (13086): #5      TdClient.clientSend (package:tdlib/src/tdclient/tdclient.dart:32:63)
E/flutter (13086): #6      TelegramService.send (package:fima/services/telegram_service.dart:195:22)
E/flutter (13086): #7      _ChatScreenState.sendMessage (package:fima/screens/main/chat.dart:210:58)
E/flutter (13086): #8      _ChatScreenState.build.<anonymous closure>.<anonymous closure> (package:fima/screens/main/chat.dart:94:50)
E/flutter (13086): #9      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:989:21)
E/flutter (13086): #10     GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (13086): #11     TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:607:11)
E/flutter (13086): #12     BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:296:5)
E/flutter (13086): #13     BaseTapGestureRecognizer.handlePrimaryPointer (package:flutter/src/gestures/tap.dart:230:7)
E/flutter (13086): #14     PrimaryPointerGestureRecognizer.handleEvent (package:flutter/src/gestures/recognizer.dart:475:9)
E/flutter (13086): #15     PointerRouter._dispatch (package:flutter/src/gestures/pointer_router.dart:93:12)
E/flutter (13086): #16     PointerRouter._dispatchEventToRoutes.<anonymous closure> (package:flutter/src/gestures/pointer_router.dart:138:9)
E/flutter (13086): #17     _LinkedHashMapMixin.forEach (dart:collection-patch/compact_hash.dart:397:8)
E/flutter (13086): #18     PointerRouter._dispatchEventToRoutes (package:flutter/src/gestures/pointer_router.dart:136:18)
E/flutter (13086): #19     PointerRouter.route (package:flutter/src/gestures/pointer_router.dart:122:7)
E/flutter (13086): #20     GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:439:19)
E/flutter (13086): #21     GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:419:22)
E/flutter (13086): #22     RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:287:11)
E/flutter (13086): #23     GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:374:7)
E/flutter (13086): #24     GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:338:5)
E/flutter (13086): #25     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:296:7)
E/flutter (13086): #26     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:279:7)
E/flutter (13086): #27     _rootRunUnary (dart:async/zone.dart:1370:13)
E/flutter (13086): #28     _CustomZone.runUnary (dart:async/zone.dart:1265:19)
E/flutter (13086): #29     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1170:7)
E/flutter (13086): #30     _invoke1 (dart:ui/hooks.dart:182:10)
E/flutter (13086): #31     PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:282:7)
E/flutter (13086): #32     _dispatchPointerDataPacket (dart:ui/hooks.dart:96:31)

【问题讨论】：

嘿@Onionus！两个选项：首先，使用调试器，查看堆栈跟踪以确定 json 编码到底在哪里失败。二、在仓库中提出问题：github.com/i-Naji/tdlib/issues
嘿，谢谢你的帮助，这是堆栈跟踪，虽然不知道是什么意思哈哈。
你在我上传的stacktrace中看到问题了吗？
对这个包有经验的人/开发它的人会很快理解堆栈跟踪。这就是为什么我建议在 github 中也打开一个问题。

标签： android flutter dart telegram tdlib

【解决方案1】：

对于曾经遇到同样问题的任何人，我想我已经解决了。 TdApi 中的函数 SendMessage() 需要“options:”参数有一个值。这可以通过对象 MessageSendOptions() 来完成。使用此文档作为参考：https://pub.dev/documentation/tdlib/latest/td_api/SendMessage-class.html

【讨论】：