颤动电子邮件发件人作为后台进程答案

【问题标题】：flutter email sender as a background process颤动电子邮件发件人作为后台进程
【发布时间】：2022-07-28 03:55:34
【问题描述】：

所以我尝试在 Flutter 中发送电子邮件作为后台进程，而无需浏览 gmail 应用程序，我按照本教程进行操作 https://www.youtube.com/watch?v=RDwst9icjAY 并且除了图标按钮上的“onpressed（）{}”功能外，所有东西都在工作，它显示在声明之前无法引用“局部变量”sendEmail”的错误。尝试将声明移至第一次使用之前，或重命名局部变量，使其不会在封闭范围内隐藏名称。没有快速修复，所以似乎是什么问题？，我尝试在多个地方初始化它，但我想我是这些类型的功能的新手。这是我的代码

    import 'package:flutter/material.dart';
    import 'package:mailer/mailer.dart';
    import 'package:mailer/smtp_server.dart';
    import 'package:google_sign_in/google_sign_in.dart';

    import 'google_auth_api.dart';

    class emailsend extends StatefulWidget {
    const emailsend({Key? key}) : super(key: key);

    @override
    State<emailsend> createState() => _MainPageState();
    }
    class _MainPageState extends State<emailsend> {

    @override
      Widget build(BuildContext context) {
      return Scaffold(
      appBar: AppBar(
        title: Text('email'),
        centerTitle: true,
      ),
      body: Center(
        child: IconButton(
          icon: Icon(Icons.circle_rounded),
          splashColor: Colors.red,
          color: Colors.red,
          iconSize: 250,
          onPressed:(){ sendEmail},
        ),
      ),
    );

    Future sendEmail() async {
      final user = await GoogleAuthApi.signIn();
      if (user == null) return;
      final email = 'khaledkandli55@gmail.com';
      final auth = await user.authentication;
      final accessToken = '';
      final smptServer = gmailSaslXoauth2(email, accessToken);
      final message = Message()
        ..from = Address(email, 'Khaled')
        ..recipients = ['khaledkandli55@gmail.com']
        ..subject = 'Hello'
        ..text = 'this is atext email';
      try {
        await send(message, smptServer);
        showSnackBar('sent successfully');
      } on MailerException catch (erorr) {
        print(erorr);
      }
    }
  }
    void showSnackBar(String text) {
    final snackBar = SnackBar(
      content: Text(
        text,
        style: TextStyle(fontSize: 20),
      ),
      backgroundColor: Colors.green,
    );
    ScaffoldMessenger.of(context)
      ..removeCurrentSnackBar()
      ..showSnackBar(snackBar);
  }
}

//第二页

import 'package:google_sign_in/google_sign_in.dart';
 class GoogleAuthApi {
 static final _googleSignIn =
  GoogleSignIn(scopes: ['https://mail.google.com/']);
 static Future<GoogleSignInAccount?> signIn() async {
  if (await _googleSignIn.isSignedIn()) {
  return _googleSignIn.currentUser;
   } else {
   return await _googleSignIn.signIn();
 }
} 
}

【问题讨论】：

标签： flutter email sms flutter-futurebuilder

【解决方案1】：

您缺少对函数的实际调用。

onPressed: () { sendEmail(); }

或者如果你想使用参考。

onPressed: sendEmail

【讨论】：

还是同样的错误

【解决方案2】：

尝试在构建之前创建 sendEmail 函数并在 onPressed 中调用它喜欢这段代码


import 'package:flutter/material.dart';
import 'package:mailer/mailer.dart';
import 'package:mailer/smtp_server.dart';
import 'package:google_sign_in/google_sign_in.dart';

class EmailSend extends StatefulWidget {
 const EmailSend({Key? key}) : super(key: key);

 @override
 State<EmailSend> createState() => _MainPageState();
}

class _MainPageState extends State<EmailSend> {
 Future sendEmail() async {
   final user = await GoogleAuthApi.signIn();
   if (user == null) return;
   final email = 'khaledkandli55@gmail.com';
   final auth = await user.authentication;
   final accessToken = '';
   final smptServer = gmailSaslXoauth2(email, accessToken);
   final message = Message()
     ..from = Address(email, 'Khaled')
     ..recipients = ['khaledkandli55@gmail.com']
     ..subject = 'Hello'
     ..text = 'this is atext email';
   try {
     await send(message, smptServer);
     showSnackBar('sent successfully');
   } on MailerException catch (erorr) {
     print(erorr);
   }
 }

 @override
 Widget build(BuildContext context) {
   return Scaffold(
     appBar: AppBar(
       title: Text('email'),
       centerTitle: true,
     ),
     body: Center(
       child: ElevatedButton(
         child: Text("Send Email"),
         onPressed: () {
           sendEmail();
         },
       ),
     ),
   );
 }

 void showSnackBar(String text) {
   final snackBar = SnackBar(
     content: Text(
       text,
       style: TextStyle(fontSize: 20),
     ),
     backgroundColor: Colors.green,
   );
   ScaffoldMessenger.of(context)
     ..removeCurrentSnackBar()
     ..showSnackBar(snackBar);
 }
}

class GoogleAuthApi {
 static final _googleSignIn =
     GoogleSignIn(scopes: ['https://mail.google.com/']);
 static Future<GoogleSignInAccount?> signIn() async {
   if (await _googleSignIn.isSignedIn()) {
     return _googleSignIn.currentUser;
   } else {
     return await _googleSignIn.signIn();
   }
 }
}

【讨论】：