Flutter执行自定义命令插件ferry_exec的使用

当然，下面是一个关于如何在Flutter项目中使用ferry_exec插件来执行自定义命令的示例代码。ferry_exec是一个假设的插件名称，用于演示目的，实际中你可能需要查找具体的插件或实现类似功能。在Flutter中，执行自定义命令通常涉及平台通道（Platform Channels）的使用。

假设我们有一个名为ferry_exec的插件，它允许我们在Flutter应用中执行自定义的操作系统命令。以下是如何在Flutter项目中集成和使用这个插件的示例代码。

1. 创建Flutter插件（假设为ferry_exec）

首先，你需要创建或找到一个能够执行自定义命令的Flutter插件。如果你自己创建，可能需要分别在iOS和Android平台上实现执行命令的功能。

iOS端（Swift）

在ios/Classes/FerryExecPlugin.swift中：

import Flutter

public class FerryExecPlugin: NSObject, FlutterPlugin {
  public static func register(with registrar: FlutterRegistrar) {
    let channel = FlutterMethodChannel(name: "ferry_exec", binaryMessenger: registrar.messenger())
    let instance = FerryExecPlugin()
    registrar.addMethodCallDelegate(instance, channel: channel)
  }

  public func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
    if call.method == "executeCommand" {
      guard let command = call.arguments as? String else {
        result(FlutterError(code: "INVALID_ARGUMENT", message: "Command must be a string", details: nil))
        return
      }
      
      let task = Process()
      task.launchPath = "/bin/bash"
      task.arguments = ["-c", command]
      
      let pipe = Pipe()
      task.standardOutput = pipe
      task.standardError = pipe
      
      task.launch()
      
      let data = pipe.fileHandleForReading.readDataToEndOfFile()
      let output = String(data: data, encoding: .utf8) ?? ""
      
      task.waitUntilExit()
      
      result(output)
    } else {
      result(FlutterMethodNotImplementedError(methodName: call.method))
    }
  }
}

Android端（Kotlin）

在android/src/main/kotlin/com/example/ferry_exec/FerryExecPlugin.kt中：

package com.example.ferry_exec

import io.flutter.embedding.engine.plugins.FlutterPlugin
import io.flutter.embedding.engine.plugins.activity.ActivityAware
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding
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 java.io.BufferedReader
import java.io.InputStreamReader
import android.os.AsyncTask

class FerryExecPlugin: FlutterPlugin, MethodCallHandler, ActivityAware {
  private lateinit var channel: MethodChannel
  private var activity: android.app.Activity? = null

  override fun onAttachedToEngine(binding: FlutterPluginBinding) {
    channel = MethodChannel(binding.binaryMessenger, "ferry_exec")
    channel.setMethodCallHandler(this)
  }

  override fun onMethodCall(call: MethodCall, result: Result) {
    if (call.method == "executeCommand") {
      val command = call.argument<String>("command") ?: return result.error("INVALID_ARGUMENT", "Command is missing", null)
      ExecuteCommandTask(command, result).execute()
    } else {
      result.notImplemented()
    }
  }

  override fun onDetachedFromEngine(binding: FlutterPluginBinding) {
    channel.setMethodCallHandler(null)
  }

  override fun onAttachedToActivity(binding: ActivityPluginBinding) {
    activity = binding.activity
  }

  override fun onDetachedFromActivityForConfigChanges() {
    activity = null
  }

  override fun onReattachedToActivityForConfigChanges(binding: ActivityPluginBinding) {
    activity = binding.activity
  }

  override fun onDetachedFromActivity() {
    activity = null
  }

  private class ExecuteCommandTask(private val command: String, private val result: Result) : AsyncTask<Void, Void, String>() {
    override fun doInBackground(vararg params: Void?): String {
      return try {
        val process = Runtime.getRuntime().exec(command)
        val reader = BufferedReader(InputStreamReader(process.inputStream))
        val output = StringBuilder()
        var line: String?
        while (reader.readLine().also { line = it } != null) {
          output.append(line).append("\n")
        }
        output.toString()
      } catch (e: Exception) {
        e.message ?: "Error executing command"
      }
    }

    override fun onPostExecute(output: String) {
      result.success(output)
    }
  }
}

2. 在Flutter项目中使用ferry_exec插件

确保在pubspec.yaml中添加你的插件依赖（假设已经发布到pub.dev或者本地路径）：

dependencies:
  flutter:
    sdk: flutter
  ferry_exec:
    path: ../path/to/your/ferry_exec/plugin  # 如果是本地开发
    # 或者
    # ferry_exec: ^0.0.1  # 如果是发布的版本

然后在你的Dart代码中调用插件：

import 'package:flutter/material.dart';
import 'package:ferry_exec/ferry_exec.dart';  // 假设插件提供了这样的导入路径

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('Ferry Exec Demo'),
        ),
        body: Center(
          child: ElevatedButton(
            onPressed: _executeCommand,
            child: Text('Execute Command'),
          ),
        ),
      ),
    );
  }

  Future<void> _executeCommand() async {
    try {
      final String result = await FerryExec.executeCommand('echo Hello, World!');
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(result)));
    } catch (e) {
      ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text('Error: $e')));
    }
  }
}

注意：上面的代码假设插件提供了一个顶层函数FerryExec.executeCommand，你需要根据实际情况调整。

这个示例展示了如何在Flutter项目中集成和使用一个自定义命令执行插件。如果你没有找到现成的ferry_exec插件，你可以参考上述代码创建自己的插件，或者查找类似的现有插件。