自定义 Facebook 登录以与 MethodChannel 一起使用

Question

我正在尝试使用一些本机代码为Flutter创建一个Facebook身份验证插件。我已经让代码在一个完全原生的测试项目上运行，但无法让它在 android 插件项目中工作。我不是Android人，所以我对此的了解非常有限。但这就是我得到的：

public class FacebookSignInPlugin implements MethodCallHandler {
  CallbackManager callbackManager;
  AccessToken token;
  /**
   * Plugin registration.
   */
  public static void registerWith(Registrar registrar) {
    final MethodChannel channel = new MethodChannel(registrar.messenger(), "facebook_sign_in");
    channel.setMethodCallHandler(new FacebookSignInPlugin());
  }

  @Override
  public void onMethodCall(MethodCall call, Result result) {
    if (call.method.equals("signInUser")) {
      callbackManager = CallbackManager.Factory.create();
      LoginManager.getInstance().registerCallback(callbackManager, new     FacebookCallback<LoginResult>() {
        @Override
        public void onSuccess(LoginResult loginResult) {
          token = loginResult.getAccessToken();
          Log.d("Facebook", token.toString());
        }
        @Override
        public void onCancel() {
          System.out.println("cancel");
          Log.d("Facebook", "Cancel");
        }
        @Override
        public void onError(FacebookException error) {
        }
      });
      login();
      result.success("It works on Android");
    } else {
      result.notImplemented();
    }
  }
  @Override
  protected void onActivityResult(final int requestCode, final int resultCode, final Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    callbackManager.onActivityResult(requestCode, resultCode, data);
  }
  public void login() {
    LoginManager.getInstance().logInWithReadPermissions(this, Arrays.asList("public_profile", "user_friends"));
  }
  public void logout() {
    LoginManager.getInstance().logOut();
  }
}

我想使用最后两个功能：登录，注销。但是在方法"onActivityResult"中，我遇到了一个无法解决onActivityResult的问题，而在"登录"中，我遇到了与loginWithReadPermissions相同的问题。一切都应该正确导入。任何有机器人经验的人都可以提供帮助吗？

Answer 1

为了在 Flutter 插件中使用 onActivityResult，您必须做两件事：

1. 实现PluginRegistry.ActivityResultListener接口
2. 将插件添加到 registerWith 静态方法中的 ActivityResultListeners 列表中。

去除MethodCall位的简化示例：

public class FacebookSignInPlugin implements MethodCallHandler,
      // Implement PluginRegistry.ActivityResultListener
      PluginRegistry.ActivityResultListener {
  public static void registerWith(Registrar registrar) {
      final MethodChannel channel = new MethodChannel(registrar.messenger(), "my_plugin");
      final FacebookSignInPlugin instance = new MyPlugin();
      // Register your plugin as an ActivityResultListener
      registrar.addActivityResultListener(instance);
      channel.setMethodCallHandler(instance);
  }
  private CallbackManager callbackManager = CallbackManager.Factory.create();
  @Override
  public void onMethodCall(MethodCall call, final Result result) {
  }
  @Override
  public boolean onActivityResult(int i, int i1, Intent intent) {
      // Forward the activity result to the Facebook CallbackManager
      callbackManager.onActivityResult(i, i1, intent);
      return false;
  }
}

<</div> div class="one_answers">

如果您在 2020 年编写自己的 Flutter 插件并尝试实现调用 onActivitResult 试试这个。与此同时，插件 API 发生了变化，除了仅在registerWith中注册侦听器外，您还必须实现 ActivityAware 接口并在 onAttachedToActivity 方法中注册ActivityResultListner：

class PayFlutterPlugin() : FlutterPlugin, MethodCallHandler, ActivityAware,
    ActivityResultListener {
   
    private var activityPluginBinding: ActivityPluginBinding? = null
    private var result: Result? = null
    override fun onAttachedToActivity(binding: ActivityPluginBinding) {
        activityPluginBinding = binding
        binding.addActivityResultListener(this)
    }
    override fun onReattachedToActivityForConfigChanges(binding: ActivityPluginBinding) {}
    override fun onDetachedFromActivityForConfigChanges() {}
    override fun onDetachedFromActivity() {
        activityPluginBinding?.removeActivityResultListener(this)
        activityPluginBinding = null
    }
    override fun onActivityResult(
        requestCode: Int,
        resultCode: Int,
        data: Intent
    ): Boolean {
        // React to activity result and if request code == ResultActivity.REQUEST_CODE
        return when (resultCode) {
            Activity.RESULT_OK -> {
                result?.success("success") // pass your result data
                true
            }
            else -> false
        }
    }
    override fun onMethodCall(@NonNull call: MethodCall, @NonNull result: Result) {
        this.result = result
        val activity = activityPluginBinding?.activity ?: return
        when (call.method) {
            "yourMethod" -> {
                val intent = Intent(activity, ResultActivity::class.java)
                activity.startActivityForResult(
                    intent,
                    ResultActivity.REQUEST_CODE
                )
            }
            else -> result.notImplemented()
        }
    }
}