Flutter文档扫描插件 document_scanner_flutter 的使用

document_scanner_flutter 是一个用于Flutter的插件，它不仅支持文档扫描功能，还可以生成PDF文件。以下是该插件的详细使用方法和示例代码。

安装

在你的 pubspec.yaml 文件中添加以下依赖：

dependencies:
  document_scanner_flutter: ^0.2.3

然后运行 flutter pub get 来安装插件。

基本用法

扫描文档并获取图像文件

import 'dart:io';
import 'package:document_scanner_flutter/document_scanner_flutter.dart';

void scanDocument() async {
  try {
    File scannedDoc = await DocumentScannerFlutter.launch();
    // `scannedDoc` 将是从扫描仪获取的图像文件
    print('Scanned Document Path: ${scannedDoc.path}');
  } on PlatformException catch (e) {
    print('Failed to get document path or operation cancelled: $e');
  }
}

指定来源（相册或相机）

void scanDocumentFromSource(ScannerFileSource source) async {
  try {
    File scannedDoc = await DocumentScannerFlutter.launch(source: source);
    // `scannedDoc` 将是从指定来源获取的图像文件
    print('Scanned Document Path: ${scannedDoc.path}');
  } on PlatformException catch (e) {
    print('Failed to get document path or operation cancelled: $e');
  }
}

新功能

PDF生成

可以将扫描的图像生成为PDF文件：

void generatePdfFromScannedImages() async {
  try {
    File pdfFile = await DocumentScannerFlutter.launchForPdf(
      source: ScannerFileSource.CAMERA,
    );
    // `pdfFile` 将是从扫描仪生成的PDF文件
    print('Generated PDF Path: ${pdfFile.path}');
  } on PlatformException catch (e) {
    print('Failed to generate PDF or operation cancelled: $e');
  }
}

Android扫描器标签自定义

可以自定义Android扫描器中的按钮标签：

void customizeAndroidLabels() async {
  var androidLabelsConfigs = {
    ScannerConfigsAndroid.ANDROID_NEXT_BUTTON_TITLE: "Next Step",
    ScannerConfigsAndroid.ANDROID_SAVE_BUTTON_TITLE: "Save It",
    ScannerConfigsAndroid.ANDROID_ROTATE_LEFT_TITLE: "Turn it left",
    ScannerConfigsAndroid.ANDROID_ROTATE_RIGHT_TITLE: "Turn it right",
    ScannerConfigsAndroid.ANDROID_ORIGINAL_TITLE: "Original",
    ScannerConfigsAndroid.ANDROID_BMW_TITLE: "B & W"
  };

  try {
    File pdfFile = await DocumentScannerFlutter.launchForPdf(
      source: ScannerFileSource.CAMERA,
      androidConfigs: androidLabelsConfigs,
    );
    print('Generated PDF Path with customized labels: ${pdfFile.path}');
  } on PlatformException catch (e) {
    print('Failed to generate PDF or operation cancelled: $e');
  }
}

示例 Demo

以下是一个完整的示例应用，展示了如何使用 document_scanner_flutter 插件进行文档和图像扫描，并生成PDF文件。

import 'dart:io';
import 'package:document_scanner_flutter/document_scanner_flutter.dart';
import 'package:document_scanner_flutter/configs/configs.dart';
import 'package:flutter/material.dart';
import 'package:advance_pdf_viewer/advance_pdf_viewer.dart';

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

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  PDFDocument? _scannedDocument;
  File? _scannedDocumentFile;
  File? _scannedImage;

  openPdfScanner(BuildContext context) async {
    var doc = await DocumentScannerFlutter.launchForPdf(
      context,
      labelsConfig: {
        ScannerLabelsConfig.ANDROID_NEXT_BUTTON_LABEL: "Next Steps",
        ScannerLabelsConfig.PDF_GALLERY_FILLED_TITLE_SINGLE: "Only 1 Page",
        ScannerLabelsConfig.PDF_GALLERY_FILLED_TITLE_MULTIPLE: "Only {PAGES_COUNT} Page"
      },
    );
    if (doc != null) {
      _scannedDocument = null;
      setState(() {});
      await Future.delayed(Duration(milliseconds: 100));
      _scannedDocumentFile = doc;
      _scannedDocument = await PDFDocument.fromFile(doc);
      setState(() {});
    }
  }

  openImageScanner(BuildContext context) async {
    var image = await DocumentScannerFlutter.launch(context, 
      labelsConfig: {
        ScannerLabelsConfig.ANDROID_NEXT_BUTTON_LABEL: "Next Step",
        ScannerLabelsConfig.ANDROID_OK_LABEL: "OK"
      });
    if (image != null) {
      _scannedImage = image;
      setState(() {});
    }
  }

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Document Scanner Demo'),
        ),
        body: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            if (_scannedDocument != null || _scannedImage != null) ...[
              if (_scannedImage != null)
                Image.file(_scannedImage!,
                    width: 300, height: 300, fit: BoxFit.contain),
              if (_scannedDocument != null)
                Expanded(
                    child: PDFViewer(
                  document: _scannedDocument!,
                )),
              Padding(
                padding: const EdgeInsets.all(8.0),
                child: Text(
                    _scannedDocumentFile?.path ?? _scannedImage?.path ?? ''),
              ),
            ],
            Center(
              child: Builder(builder: (context) {
                return ElevatedButton(
                    onPressed: () => openPdfScanner(context),
                    child: Text("PDF Scan"));
              }),
            ),
            Center(
              child: Builder(builder: (context) {
                return ElevatedButton(
                    onPressed: () => openImageScanner(context),
                    child: Text("Image Scan"));
              }),
            )
          ],
        ),
      ),
    );
  }
}

以上示例展示了如何使用 document_scanner_flutter 插件进行文档和图像扫描，并生成PDF文件。你可以根据需要自定义扫描器标签和选择扫描源。