Android Print Service #

Flutter plugin to print documents on Android devices using native print service.
This plugin supports both sharing documents while the app is running and when the app is closed.

Features #

• Receive documents shared from other apps.
• Preview received files inside your Flutter app.
• Works on Android with proper system alert window permission.

Installation #

Add this to your pubspec.yaml:

dependencies:
  android_printer_service: ^0.0.3

Demo #

Usage #

Below is a concise example showing how to handle shared documents and preview them:

import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:android_printer_service/android_printer_service.dart';
import 'package:permission_handler/permission_handler.dart';

class MyHomePage extends StatefulWidget {
  const MyHomePage({super.key});

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
  late StreamSubscription _forwardPrintStreamSubs;
  String pathFile = '';

  @override
  void initState() {
    super.initState();

    // 1. Wait for the widget tree to finish building
    WidgetsBinding.instance.addPostFrameCallback((_) {
      // 2. Request System Alert Window permission
      _requestPermissionSystemAlert();

      // 3. Delay before starting to listen to document stream
      Future.delayed(const Duration(milliseconds: 320), () {
        _onForwardPrintStreamSubs();
      });
    });
  }

  // 4. Listen to shared documents
  void _onForwardPrintStreamSubs() {
    // Set the printer service name
    ForwardPrinter.setPrinterName("My_Printer_Service");

    // a) Listen for documents while the app is running
    _forwardPrintStreamSubs = ForwardPrinter.getDocumentStream().listen(
      _onForwardFile,
    );

    // b) Receive document if the app was just launched (previously closed)
    ForwardPrinter.getInitialDocument().then(_onForwardFile);
  }

  // 5. Handle received file
  void _onForwardFile(String? jsonStr) {
    if (jsonStr == null) return;

    final file = PrintFile.fromJson(jsonDecode(jsonStr));

    _onPreviewFiles([file.path]);
  }

  // 6. Display the file inside the app
  void _onPreviewFiles(List<String> paths) async {
    setState(() {
      pathFile = paths.first; // preview only the first file
    });
  }

  // 7. Request System Alert Window permission
  Future<void> _requestPermissionSystemAlert() async {
    if (Platform.isAndroid && context.mounted) {
      final status = await Permission.systemAlertWindow.status;
      if (status != PermissionStatus.granted) {
        final allow = await showDialog<bool>(
          context: context,
          builder: (context) => AlertDialog(
            title: const Text("Permission Required"),
            content: const Text(
              "This app needs permission to run the Printer Service properly. Do you want to allow it?",
            ),
            actions: [
              TextButton(
                onPressed: () => Navigator.of(context).pop(false),
                child: const Text("Deny"),
              ),
              TextButton(
                onPressed: () => Navigator.of(context).pop(true),
                child: const Text("Allow"),
              ),
            ],
          ),
        );

        if (allow == true) {
          await Future.delayed(
            const Duration(milliseconds: 150),
            () => Permission.systemAlertWindow.request(),
          );
        }
      }
    }
  }

  @override
  void dispose() {
    // 8. Cancel the stream when the widget is disposed
    _forwardPrintStreamSubs.cancel();
    super.dispose();
  }
}

Donate #

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