尝试直接从 FLUTTER 进行调用：MissingPluginException（未找到方法 callNumber 的实现

Question

我希望我的应用程序在出现特定情况时自动呼叫特定号码。两个流行的插件是 flutter_phone_direct_caller 和 url_launcher。 Url 启动器的问题是该方法会将号码推送到您的 phone 的拨号器，但不会启动呼叫，但 flutter_phone_direct_caller 声称它会启动。这是他们文档中的示例。

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

void main() {
  runApp(Scaffold(
    body: Center(
      child: RaisedButton(
        onPressed: _callNumber,
        child: Text('Call Number'),
      ),
    ),
  ));
}

_callNumber() async{
  const number = '08592119XXXX'; //set the number here
  bool res = await FlutterPhoneDirectCaller.callNumber(number);
}

这是我页面的代码。当按下按钮时，呼叫应该启动，但对我来说，它 returns 是一个错误。（我的 phone 号码是 XXXd，当我运行它是我输入的实际编号）。

import 'package:flutter/material.dart';
import 'package:url_launcher/url_launcher.dart';
import 'package:vitality/components/bottomAppBar.dart';
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:firebase_auth/firebase_auth.dart';
import 'package:vitality/components/biom.dart';
import 'package:flutter_phone_direct_caller/flutter_phone_direct_caller.dart';

class HomeScreen extends StatefulWidget {
  static const String id = 'home_screen';
  final String docid;
  final bool isCaretaker;
  HomeScreen({@required this.docid, @required this.isCaretaker});
  @override
  _HomeScreenState createState() => _HomeScreenState();
}

_callNumber() async {
  const number = '86065XXXXX'; //set the number here
  bool res = await FlutterPhoneDirectCaller.callNumber(number);
}

class _HomeScreenState extends State<HomeScreen> {
  final auth = FirebaseAuth.instance;
  var pulse;
  var temp;
  @override
  Widget build(BuildContext context) {
    print('got here');
    print(auth.currentUser.uid);
    String id = ModalRoute.of(context).settings.arguments;

    CollectionReference main = FirebaseFirestore.instance.collection('maindb');
    main.doc(id).get().then((DocumentSnapshot documentSnapshot) {
      if (documentSnapshot.exists) {
        print('Document exists on the database');
        pulse = documentSnapshot['pulse'];
        temp = documentSnapshot['temperature'];
      }
    });
    return Scaffold(
      backgroundColor: Colors.white,
      appBar: AppBar(
          backgroundColor: Color(0xFF602247),
          toolbarHeight: 50.0,
          centerTitle: true,
          title: Text(
            'HEALTH TRACKER',
            style: Theme.of(context).textTheme.headline4,
          )),
      body: Container(
        decoration: BoxDecoration(
            image: DecorationImage(
          image:
              NetworkImage('https://cdn.wallpapersafari.com/12/24/GiZRfh.jpg'),
          fit: BoxFit.cover,
          colorFilter: new ColorFilter.mode(
              Colors.black.withOpacity(.7), BlendMode.dstATop),
        )),
        child: Column(
            crossAxisAlignment: CrossAxisAlignment.center,
            mainAxisAlignment: MainAxisAlignment.spaceEvenly,
            children: <Widget>[
              Text(widget.docid),
              Text({widget.isCaretaker}.toString()),
              biom(which: 'pulse', image: 'pulse', docid: widget.docid),
              RoundBorderText(text: 'PULSE'),
              biom(which: 'temperature', image: 'temper', docid: widget.docid),
              RoundBorderText(text: 'TEMPERATURE'),
              SizedBox(height: 30.0),
              FlatButton(
                  child: Text('test call'),
                  onPressed: () async {
                    FlutterPhoneDirectCaller.callNumber('5');
                  })
            ]),
      ),
      bottomNavigationBar: bottomAppBar(id: widget.docid),
    );
  }
}

class RoundBorderText extends StatelessWidget {
  final String text;
  RoundBorderText({this.text});
  @override
  Widget build(BuildContext context) {
    return Container(
        padding: const EdgeInsets.only(
            left: 40.0, right: 40.0, top: 8.0, bottom: 8.0),
        decoration: BoxDecoration(
            // border: Border.all(
            //   color: Colors.black,
            //   width: 1.0,
            // ),
            borderRadius: BorderRadius.all(Radius.circular(20))),
        child: Text(text, style: Theme.of(context).textTheme.headline1));
  }
}

E/flutter (23210): [错误:flutter/lib/ui/ui_dart_state.cc(186)] 未处理的异常：MissingPluginException（未在通道 flutter_phone_direct_caller 上找到方法 callNumber 的实现）

这个插件有 94% 的流行度，所以它适用于大多数人。有谁知道问题出在哪里？

Answer 1

flutter 与本机功能集成的方式是创建所谓的 MethodChannels，使用它们可以调用在 dart 的本机 java 代码中注册的函数。

所以出现此错误的原因之一是您的 flutter 代码无法与本机 java 代码通信，这意味着它没有找到任何 channel 或者它没有找到method通过包注册了channel那里。

我怀疑这可能是构建问题。

步骤

从您的设备上卸载该应用程序。
再次重建应用。

这应该可以解决问题。

尝试直接从 FLUTTER 进行调用：MissingPluginException（未找到方法 callNumber 的实现

TRYING TO PLACE CALL DIRECTLY FROM FLUTTER: MissingPluginException(No implementation found for method callNumber

plugins

phone-call

dart

flutter