Flutter绘图App中如何禁用Apple Pencil的Scribble及检测笔身点击？

一、自动禁用Apple Pencil Scribble功能 #

Flutter本身没有直接控制Scribble的API，需通过iOS原生代码实现App启动时自动禁用：

1. 打开iOS项目的AppDelegate.swift文件
2. 在didFinishLaunchingWithOptions方法中添加代码，禁用Flutter视图的Scribble交互：

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
    
    // 禁用Apple Pencil Scribble功能
    if let flutterView = window?.rootViewController?.view as? FlutterView {
      flutterView.scribbleInteraction?.isEnabled = false
    }
    
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}

App启动后会自动关闭Scribble，无需用户手动在系统设置中操作。

二、检测Apple Pencil笔身点击操作 #

Flutter无法直接捕获笔身按键事件，需通过iOS原生监听远程控制事件，再通过MethodChannel传递到Flutter层：

iOS端代码（AppDelegate.swift） #

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  private let pencilChannel = FlutterMethodChannel(name: "pencil_control", binaryMessenger: UIApplication.shared.delegate as! FlutterBinaryMessenger)
  
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
    
    // 开启远程控制事件监听
    application.beginReceivingRemoteControlEvents()
    
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
  
  override func remoteControlReceived(with event: UIEvent?) {
    guard let event = event, event.type == .remoteControl else { return }
    
    // Apple Pencil单次点击对应远程控制的播放/暂停事件
    if event.subtype == .remoteControlPlayPause {
      pencilChannel.invokeMethod("pencil_button_tapped", arguments: nil)
    }
  }
}

Flutter端代码 #

import 'package:flutter/services.dart';

void main() {
  runApp(const MyApp());
  // 初始化Apple Pencil按键监听
  _initPencilButtonListener();
}

void _initPencilButtonListener() {
  const MethodChannel _pencilChannel = MethodChannel('pencil_control');
  _pencilChannel.setMethodCallHandler((MethodCall call) async {
    if (call.method == 'pencil_button_tapped') {
      // 在这里实现工具切换逻辑，比如切换到橡皮擦
      print("Apple Pencil按键被点击，切换至橡皮擦");
      // 你的工具切换代码
    }
  });
}

注意：Apple Pencil的按键事件会被识别为系统远程控制的播放/暂停事件，如果App内有音频播放功能，需额外处理避免冲突。

内容的提问来源于stack exchange，提问作者Kevin Yang