flutter优雅实现扫码枪获取数据源示例详解

mixin TextInputBindingMixin on WidgetsFlutterBinding {
  @override
  BinaryMessenger createBinaryMessenger() {
    return TextInputBinaryMessenger(super.createBinaryMessenger());
  }
}

class TextInputBinding extends WidgetsFlutterBinding with TextInputBindingMixin {}
 void main() {
   TextInputBinding();
   runApp(const MyApp());
 }

class TextInputBinaryMessenger extends BinaryMessenger {
  TextInputBinaryMessenger(this.origin);
  final BinaryMessenger origin;
  // Flutter 的 Framework 层发送信息到 Flutter 引擎，会走这个方法
  @override
  Future<ByteData?>? send(
    String channel,
    ByteData? message,
  ) {
    //TODO  拦截处理
  }
  // Flutter 引擎 发送信息到 Flutter 的 Framework 层的回调，无需处理
  @override
  void setMessageHandler(
    String channel,
    MessageHandler? handler,
  ) {
    ... 省略
  }
  //无需处理
  @override
  Future<void> handlePlatformMessage(
    String channel,
    ByteData? data,
    PlatformMessageResponseCallback? callback,
  ) {
    ... 省略
  }
}

import 'package:flutter/material.dart';
class TextInputFocusNode extends FocusNode {
  bool ignoreSystemKeyboardShow = true;
}

@override
  Future<ByteData?>? send(
    String channel,
    ByteData? message,
  ) {
    if (channel == SystemChannels.textInput.name) {
      final methodCall = SystemChannels.textInput.codec.decodeMethodCall(
        message,
      );
      switch (methodCall.method) {
        case 'TextInput.show':
          final FocusNode? focus = FocusManager.instance.primaryFocus;
          if (focus != null &&
              focus is TextInputFocusNode &&
              focus.ignoreSystemKeyboardShow) {
            return Future.value(
              SystemChannels.textInput.codec.encodeSuccessEnvelope(null),
            );
          }
          break;
        default:
          break;
      }
    }
    return origin.send(channel, message);
  }

dependencies:
  scan_gun: ^2.0.0

  ScanMonitorWidget({
    Key? key,
    required ChildBuilder childBuilder,
    TextInputFocusNode? scanNode,
    FocusNode? textFiledNode,
    required void Function(String) onSubmit,
  })

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