如何从颤动中正确调用android本机代码（android/IOS）？

Posted 2023-02-23

【中文标题】如何从颤动中正确调用android本机代码（android/IOS）？

【英文标题】：how to call android native code(both android/IOS) properly from flutter?

【发布时间】：2020-05-10 17:48:42

【问题描述】：

我是 Flutter 的初学者。老实说不知道android Studio。 我的目标是实现本地（系统）身份验证。所以得到了local_auth 插件，它只给你一个指纹选项。如果用户没有指纹硬件怎么办？所以我打算通过从flutter调用原生代码（Android）来实现这个东西。 但问题是我无法正确验证用户身份。 例如，在进行身份验证时，响应来自本机代码。 在进行身份验证之前，我无法暂停函数的执行。尝试过同步方法 但仍然没有运气。

我的飞镖代码：

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

void main() => runApp(Container(
  child:   Row(
    children: <Widget>[
          Column(
        children: <Widget>[
              Padding(
            padding: const EdgeInsets.all(8.0),
            child:   Center(child: MyApp()),
          ),
        ],
      ),
    ],
  ),
));

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'),
    );
  


class MyHomePage extends StatefulWidget 
  MyHomePage(Key key, this.title) : super(key: key);
  final String title;

  @override
  _MyHomePageState createState() => _MyHomePageState();


class _MyHomePageState extends State<MyHomePage> 
  int _counter = 0;

  void _incrementCounter() 
//    setState(() 
//      // This call to setState tells the Flutter framework that something has
//      // changed in this State, which causes it to rerun the build method below
//      // so that the display can reflect the updated values. If we changed
//      // _counter without calling setState(), then the build method would not be
//      // called again, and so nothing would appear to happen.
//      _counter++;
//    );
//    my_count();
//  var cc = code().toString();
//  print(cc);
//    if(cc == "200") 
//      Navigator.push(
//        context,
//        MaterialPageRoute(builder: (context) => SecondRoute()),
//      );
//    else if( cc == "333") 
//      Navigator.push(context,
//      MaterialPageRoute(
//        builder: (context) => ThirdRoute()
//      ));
//    
  code();

  

  @override
  void initState() 
    // TODO: implement initState
    super.initState();
    my_count();
  

  @override
  Widget build(BuildContext context) 
    return Scaffold(
      appBar: AppBar(
        // Here we take the value from the MyHomePage object that was created by
        // the App.build method, and use it to set our appbar title.
        title: Text(widget.title),
      ),
      body: Center(
        // Center is a layout widget. It takes a single child and positions it
        // in the middle of the parent.
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: <Widget>[
            Text(
              'You have pushed the button this many times:',
            ),
            Text(
              '$_counter',
              style: Theme.of(context).textTheme.display1,
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: _incrementCounter,
        tooltip: 'Increment',
        child: Icon(Icons.add),
      ), // This trailing comma makes auto-formatting nicer for build methods.
    );
  
  static const paltform = const MethodChannel('lock');

  // ignore: missing_return
  void code() async 
    int ii;
    try 
      ii = await paltform.invokeMethod('value');
     catch (e)
      print(e);
    
//    print(ii);
//    return ii;
    if(ii == 200) 
      Navigator.push(
        context,
        MaterialPageRoute(builder: (context) => SecondRoute()),
      );
    else if( ii == 333) 
      Navigator.push(context,
          MaterialPageRoute(
              builder: (context) => ThirdRoute()
          ));
    
  

  // ignore: non_constant_identifier_names
  void my_count() async 
    try
      _counter = await paltform.invokeMethod('getCounter');
    catch(e)
      print(e);
    
  
   //if i call code() here it not executing
  code();




class SecondRoute extends StatelessWidget 
  @override
  Widget build(BuildContext context) 
    return Scaffold(
      appBar: AppBar(
        title: Text("Second Route"),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: () 
            // Navigate back to first route when tapped.
            Navigator.pop(context);
          ,
          child: Text('Go back!'),
        ),
      ),
    );
  


class ThirdRoute extends StatelessWidget 
  @override
  Widget build(BuildContext context) 
    return Scaffold(
      appBar: AppBar(
        title: Text("Third Route"),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: () 
            // Navigate back to first route when tapped.
            Navigator.pop(context);
          ,
          child: Text('Go back!'),
        ),
      ),
    );
  

我正在做的是从颤振调用本机代码并从本机端获取响应代码 基于该路由页面 这是我的 Android 代码：

package com.example.native_3;

import androidx.annotation.NonNull;
import androidx.annotation.RequiresApi;

import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugins.GeneratedPluginRegistrant;

import android.app.KeyguardManager;
import android.content.Intent;
import android.os.Build;

public class MainActivity extends FlutterActivity 

  private static final int LOCK_REQUEST_CODE = 221;
  private static final int SECURITY_SETTING_REQUEST_CODE = 233;
  int code = 0;
  private static final String CHANNEL = "lock";

  @Override
  public void configureFlutterEngine(@NonNull FlutterEngine flutterEngine) 
    GeneratedPluginRegistrant.registerWith(flutterEngine);
    new MethodChannel(flutterEngine.getDartExecutor().getBinaryMessenger(), CHANNEL)
            .setMethodCallHandler(
                    (call, result) -> 
                      // Note: this method is invoked on the main thread.
                      if (call.method.equals("getCounter")) 
                        synchronized (this) 
                          authenticateApp();
                        
                        int batteryLevel = 0;


                        if (batteryLevel >= 0) 
                          result.success(batteryLevel);
                         else 
                          result.error("UNAVAILABLE", "Battery level not available.", null);
                        
                       else if (call.method.equals("value")) 
                        result.success(get());
                      
                      else 
                        result.notImplemented();
                      
                    
            );
  

  private int get() 
    return code;
  

  private synchronized void authenticateApp() 
    //Get the instance of KeyGuardManager
    KeyguardManager keyguardManager = (KeyguardManager) getSystemService(KEYGUARD_SERVICE);

    //Check if the device version is greater than or equal to Lollipop(21)
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) 
      //Create an intent to open device screen lock screen to authenticate
      //Pass the Screen Lock screen Title and Description
      Intent i = keyguardManager.createConfirmDeviceCredentialIntent("unlock", "to unlock");
      try 
        //Start activity for result
        startActivityForResult(i, LOCK_REQUEST_CODE);

       catch (Exception e) 

//        //If some exception occurs means Screen lock is not set up please set screen lock
//        //Open Security screen directly to enable patter lock
//        Intent intent = new Intent(Settings.ACTION_SECURITY_SETTINGS);
//        try 
//
//          //Start activity for result
//          startActivityForResult(intent, SECURITY_SETTING_REQUEST_CODE);
//         catch (Exception ex) 
//
//          //If app is unable to find any Security settings then user has to set screen lock manually
//          textView.setText(getResources().getString(R.string.setting_label));
//        
      
    
  

  @Override
  protected void onActivityResult(int requestCode, int resultCode, Intent data) 
//    super.onActivityResult(requestCode, resultCode, data);
    synchronized (this) 
      switch (requestCode) 
        case LOCK_REQUEST_CODE:
          if (resultCode == RESULT_OK) 
            //If screen lock authentication is success update text
            code = 200;
           else 
            //If screen lock authentication is failed update text
            code = 333;
          
          break;
        case SECURITY_SETTING_REQUEST_CODE:
          //When user is enabled Security settings then we don't get any kind of RESULT_OK
          //So we need to check whether device has enabled screen lock or not
          if (isDeviceSecure()) 
            //If screen lock enabled show toast and start intent to authenticate user
            code = 444;
           else 
            //If screen lock is not enabled just update text

            code = 555;
          

          break;
      
    
  
  private boolean isDeviceSecure() 
    KeyguardManager keyguardManager = (KeyguardManager) getSystemService(KEYGUARD_SERVICE);

    //this method only work whose api level is greater than or equal to Jelly_Bean (16)
    return Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN && keyguardManager.isKeyguardSecure();

    //You can also use keyguardManager.isDeviceSecure(); but it requires API Level 23

  

  

运行它们后，我只有在按下按钮后才会得到成功的响应。 但我希望它应该根据本机代码的响应相应地路由自己

【参考方案1】：

local_auth 还允许进行 pin、模式或密码验证。您可以通过auth.getAvailableBiometrics()获取设备可用的生物特征认证列表。