最近打算研究一下Flutter，做一个可以浏览Samba的共享的文件浏览器。发现Flutter没有现成的插件可以用（libdsm不好用）。

于是就打算自己写一个插件。

Flutter的扩展分为2中，package和plugin。package是用纯dart实现，plugin可以调用平台原生代码。我打算封装一下smbj这个java实现的smb库。所以这里选择plugin。

参考这篇官方的文档：

首先，我们创建一个项目：

flutter create --org com.example --template=plugin --platforms=android -a java smbj

然后使用Android Studio打开这个项目。

然后在project视图中，选择android[smbj_android]右键单击，选择flutter-->Open Android module in Android Studio，在新的窗口打开android项目。

接着我们在新的Android Studio窗口中添加项目依赖。

File --> Project Structure，打开Project Structure对话框。选择Dependencies页。

点击小+号，Add Dependency。

Add Library Dependency，选择smbj：

添加依赖：'com.hierynomus:smbj:0.11.5' 'org.slf4j:slf4j-simple:1.7.36'

将SmbjPlugin.java文件替换成：

package biz.bbfox.smbj;import androidx.annotation.NonNull;import io.flutter.embedding.engine.plugins.FlutterPlugin;import io.flutter.plugin.common.BinaryMessenger;import io.flutter.plugin.common.MethodCall;import io.flutter.plugin.common.MethodChannel;import io.flutter.plugin.common.MethodChannel.MethodCallHandler;import io.flutter.plugin.common.MethodChannel.Result;import io.flutter.plugin.common.StandardMethodCodec;import com.hierynomus.msfscc.fileinformation.FileIdBothDirectoryInformation;import com.hierynomus.smbj.SMBClient;import com.hierynomus.smbj.SmbConfig;import com.hierynomus.smbj.auth.AuthenticationContext;import com.hierynomus.smbj.connection.Connection;import com.hierynomus.smbj.session.Session;import com.hierynomus.smbj.share.DiskShare;import java.io.IOException;/** * SmbjPlugin */public class SmbjPlugin implements FlutterPlugin, MethodCallHandler {    /// The MethodChannel that will the communication between Flutter and native Android    ///    /// This local reference serves to register the plugin with the Flutter Engine and unregister it    /// when the Flutter Engine is detached from the Activity    private MethodChannel channel;    @Override    public void onAttachedToEngine(@NonNull FlutterPluginBinding flutterPluginBinding) {//        channel = new MethodChannel(flutterPluginBinding.getBinaryMessenger(), "smbj");//        channel.setMethodCallHandler(this);        BinaryMessenger messenger = flutterPluginBinding.getBinaryMessenger();        BinaryMessenger.TaskQueue taskQueue =                messenger.makeBackgroundTaskQueue();        channel =                new MethodChannel(                        messenger,                        "smbj",                        StandardMethodCodec.INSTANCE,                        taskQueue);        channel.setMethodCallHandler(this);    }    @Override    public void onMethodCall(@NonNull MethodCall call, @NonNull Result result) {        if (call.method.equals("getPlatformVersion")) {            result.success("Android " + android.os.Build.VERSION.RELEASE);        } else if (call.method.equals("connectSmb")) {            SmbConfig config = SmbConfig.builder().withMultiProtocolNegotiate(true).build();            SMBClient client = new SMBClient(config);            String serverName = "your-ip";            String user = "your name";            String password = "your password";            try (Connection connection = client.connect(serverName)) {                AuthenticationContext ac = new AuthenticationContext(user, password.toCharArray(), "DOMAIN");                Session session = connection.authenticate(ac);                // Connect to Share                try (DiskShare share = (DiskShare) session.connectShare("F")) {                    for (FileIdBothDirectoryInformation f : share.list("", "*")) {                        System.out.println("File : " + f.getFileName());                    }                }            } catch (IOException e) {                e.printStackTrace();            }        } else {            result.notImplemented();        }    }    @Override    public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {        channel.setMethodCallHandler(null);    }}

这样platform一侧就准备好了。

现在来做dart这一侧：

打开文件lib/smbj.dart，添加以下代码：

  static Future<void> connectSmb() async {    await _channel.invokeListMethod('connectSmb');  }

然后在main.dart中调用：

@override  Widget build(BuildContext context) {    return MaterialApp(      home: Scaffold(        appBar: AppBar(          title: const Text('Plugin example app'),        ),        body: Center(            child: Column(          children: <Widget>[            Text('Running on: $_platformVersion\n'),            IconButton(onPressed: () {Smbj.connectSmb();}, icon: const Icon(Icons.add)),          ],        )),      ),    );  }

这样一个简单的示例就做好了。下面是运行之后的输出，可以看到相应的文件夹已经被list出来：

W/System.err(19765): [flutter-worker-3] INFO com.hierynomus.smbj.connection.PacketEncryptor - Initialized PacketEncryptor with Cipher << AES_128_GCM >>W/System.err(19765): [flutter-worker-3] INFO com.hierynomus.smbj.connection.Connection - Successfully connected to: your-ipW/System.err(19765): [flutter-worker-3] INFO com.hierynomus.smbj.connection.SMBSessionBuilder - Successfully authenticated share on 192.168.3.12, session is 149534051139605W/System.err(19765): [flutter-worker-3] INFO com.hierynomus.smbj.session.Session - Connecting to \\your-ip\F on session 149534051139605I/System.out(19765): File : $RECYCLE.BINI/System.out(19765): File : $UGMI/System.out(19765): File : 资料

这只是一个示例，等后面有时间了，把这个plugin完善好。