Flutter 采集

通过 platform channel 从 Flutter 应用中打开采集。

Markdown

您的后端使用 Journey 流程和一个采用您应用 URL scheme 的 callbackUri 在 Human Plugin 中创建流程。MethodChannel 会在 iOS 的 ASWebAuthenticationSession 和 Android 的 Custom Tabs 中打开响应里的 link。无需任何外部包。

请保留创建响应中的 Human Plugin id。您的后端用它来读取结果。

前提条件

• Flutter 3 或更高版本
• iOS 需要 Xcode 14 或更高版本
• Android 需要 Android Studio
• 您应用独有的 URL scheme，例如 myapp

1. 使用您的 scheme 创建流程

您的后端将该 scheme 作为 callbackUri 发送：

{
  "flow": "humantoken",
  "clientId": "client-a",
  "correlationId": "order-1001",
  "credential": { "type": "DUI_TYPE_NG_BVN", "value": "<document number>" },
  "callbackUri": "myapp://callback"
}

并将 id 和 link 返回给应用。

2. 创建 Dart 服务

// lib/services/capture_service.dart
import 'package:flutter/services.dart';

class CaptureService {
  static const _channel = MethodChannel('capture_plugin');

  /// Returns true when the capture ended, false when the person closed it.
  Future<bool> open(String link) async {
    try {
      final result = await _channel.invokeMethod<String>('openSession', {'url': link});
      return result != null;
    } on PlatformException {
      return false;
    }
  }
}

3. 实现 iOS 插件

// ios/Runner/CapturePlugin.swift
import Flutter
import AuthenticationServices

class CapturePlugin: NSObject, FlutterPlugin, ASWebAuthenticationPresentationContextProviding {
    private var session: ASWebAuthenticationSession?

    static func register(with registrar: FlutterPluginRegistrar) {
        let channel = FlutterMethodChannel(name: "capture_plugin", binaryMessenger: registrar.messenger())
        let instance = CapturePlugin()
        registrar.addMethodCallDelegate(instance, channel: channel)
    }

    func handle(_ call: FlutterMethodCall, result: @escaping FlutterResult) {
        guard call.method == "openSession",
              let args = call.arguments as? [String: Any],
              let urlString = args["url"] as? String,
              let url = URL(string: urlString) else {
            result(FlutterMethodNotImplemented)
            return
        }

        let newSession = ASWebAuthenticationSession(
            url: url,
            callbackURLScheme: "myapp"
        ) { callbackURL, error in
            self.session = nil
            if let callbackURL = callbackURL {
                result(callbackURL.absoluteString)
            } else {
                result(FlutterError(code: "SESSION_ERROR",
                                    message: error?.localizedDescription ?? "Session cancelled",
                                    details: nil))
            }
        }
        newSession.presentationContextProvider = self
        newSession.prefersEphemeralWebBrowserSession = true
        newSession.start()
        session = newSession
    }

    func presentationAnchor(for session: ASWebAuthenticationSession) -> ASPresentationAnchor {
        guard let windowScene = UIApplication.shared.connectedScenes.first as? UIWindowScene,
              let window = windowScene.windows.first else {
            return ASPresentationAnchor()
        }
        return window
    }
}

在 AppDelegate.swift 中注册：

CapturePlugin.register(with: self.registrar(forPlugin: "CapturePlugin")!)

4. 实现 Android 插件

将依赖添加到 android/app/build.gradle：

implementation("androidx.browser:browser:1.5.0")

// android/app/src/main/kotlin/<your.package>/CapturePlugin.kt
package com.yourapp

import android.net.Uri
import androidx.browser.customtabs.CustomTabsIntent
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

class CapturePlugin : FlutterPlugin, MethodChannel.MethodCallHandler, ActivityAware {
    private var channel: MethodChannel? = null
    private var binding: ActivityPluginBinding? = null
    private var pendingResult: MethodChannel.Result? = null

    override fun onAttachedToEngine(flutterBinding: FlutterPlugin.FlutterPluginBinding) {
        channel = MethodChannel(flutterBinding.binaryMessenger, "capture_plugin")
        channel?.setMethodCallHandler(this)
    }

    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
        if (call.method == "openSession") {
            val url = call.argument<String>("url") ?: return result.error("MISSING_URL", "URL is required", null)
            pendingResult = result
            val activity = binding?.activity ?: return result.error("NO_ACTIVITY", "No activity", null)
            CustomTabsIntent.Builder().build().launchUrl(activity, Uri.parse(url))
        } else {
            result.notImplemented()
        }
    }

    fun handleRedirect(uri: Uri) {
        if (uri.scheme == "myapp") {
            pendingResult?.success(uri.toString())
            pendingResult = null
        }
    }

    override fun onAttachedToActivity(binding: ActivityPluginBinding) { this.binding = binding }
    override fun onDetachedFromActivity() { binding = null }
    override fun onReattachedToActivityForConfigChanges(binding: ActivityPluginBinding) { this.binding = binding }
    override fun onDetachedFromActivityForConfigChanges() { binding = null }
    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) { channel = null }
}

在 MainActivity.kt 中注册并处理返回：

override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
    super.configureFlutterEngine(flutterEngine)
    flutterEngine.plugins.add(CapturePlugin())
}

override fun onNewIntent(intent: Intent) {
    super.onNewIntent(intent)
    intent.data?.let { uri ->
        if (uri.scheme == "myapp") {
            val plugin = flutterEngine?.plugins?.get(CapturePlugin::class.java) as? CapturePlugin
            plugin?.handleRedirect(uri)
        }
    }
}

5. 注册您的 scheme

iOS

在 Info.plist 中：

<key>CFBundleURLTypes</key>
<array>
    <dict>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>myapp</string>
        </array>
    </dict>
</array>

Android

在 AndroidManifest.xml 中，位于您的主 <activity> 内：

<intent-filter>
    <action android:name="android.intent.action.VIEW" />
    <category android:name="android.intent.category.DEFAULT" />
    <category android:name="android.intent.category.BROWSABLE" />
    <data android:scheme="myapp" android:host="callback" />
</intent-filter>

6. 启动采集

final ended = await CaptureService().open(link);

if (ended) {
  // The capture ended. Ask your back-end to read the outcome
  // with GET /v1/processes/{id}, using the Human Plugin id.
} else {
  // The person closed the session.
}

总结

文件	用途
lib/services/capture_service.dart	Dart MethodChannel 服务
ios/Runner/CapturePlugin.swift	iOS：ASWebAuthenticationSession
ios/Runner/AppDelegate.swift	插件注册
android/.../CapturePlugin.kt	Android：Custom Tabs
android/.../MainActivity.kt	插件注册与返回处理
Info.plist	iOS URL scheme
AndroidManifest.xml	Android intent filter