如何在flutter中使用文本识别？

import 'package:flutter/material.dart';
import 'package:firebase_ml_vision/firebase_ml_vision.dart';

class TextRecognitionScreen extends StatefulWidget {
  @override
  _TextRecognitionScreenState createState() => _TextRecognitionScreenState();
}

class _TextRecognitionScreenState extends State<TextRecognitionScreen> {
  FirebaseVisionTextRecognizer _textRecognizer;

  @override
  void initState() {
    super.initState();
    _textRecognizer = FirebaseVision.instance.textRecognizer();
  }

  @override
  void dispose() {
    _textRecognizer.close();
    super.dispose();
  }

  Future<void> _recognizeText() async {
    // 选择图像并将其转换为Firebase ML Kit可以处理的格式
    // 这里使用了一个假设的图像路径，实际情况中需要根据具体需求来获取图像
    final image = FirebaseVisionImage.fromFilePath('path_to_image');

    // 对图像进行文本识别
    final visionText = await _textRecognizer.processImage(image);

    // 处理识别结果
    for (TextBlock block in visionText.blocks) {
      for (TextLine line in block.lines) {
        for (TextElement element in line.elements) {
          print(element.text);
        }
      }
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Text Recognition'),
      ),
      body: Center(
        child: RaisedButton(
          onPressed: _recognizeText,
          child: Text('Recognize Text'),
        ),
      ),
    );
  }
}