.NET MAUIでAndroid上のバーコードを読み書きする方法

<ItemGroup Condition="$(TargetFramework.Contains('android')) == true">
    <PackageReference Include="BarCode.Android" Version="2025.3.4" />
</ItemGroup>

<AndroidBundleConfigurationFile>BundleConfig.json</AndroidBundleConfigurationFile>

<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="IronBarcodeMauiAndroid.MainPage">

    <VerticalStackLayout Padding="20">
        <HorizontalStackLayout>
            <CheckBox x:Name="generatePdfCheckBox" IsChecked="{Binding IsGeneratePdfChecked}" />
            <Label Text="PDF (unchecked for PNG)" VerticalOptions="Center"/>
        </HorizontalStackLayout>

        <Entry x:Name="barcodeInput" Placeholder="Enter barcode value..." />
        <Button Text="Generate and save barcode" Clicked="WriteBarcode" />

        <Entry x:Name="qrInput" Placeholder="Enter QR code value..." />
        <Button Text="Generate and save QR code" Clicked="WriteQRcode" />

        <Button
        Text="Read Barcode"
        Clicked="ReadBarcode"
        Grid.Row="0"
        HorizontalOptions="Center"
        Margin="20, 20, 20, 10"/>
        <ScrollView
        Grid.Row="1"
        BackgroundColor="LightGray"
        Padding="10"
        Margin="10, 10, 10, 30">
            <Label x:Name="OutputText"/>
        </ScrollView>
    </VerticalStackLayout>

</ContentPage>

using IronBarCode;

namespace IronBarcodeMauiAndroid
{
    public partial class MainPage : ContentPage
    {
        public bool IsGeneratePdfChecked
        {
            get => generatePdfCheckBox.IsChecked;
            set
            {
                generatePdfCheckBox.IsChecked = value;
            }
        }

        public MainPage()
        {
            InitializeComponent();
            License.LicenseKey = "IRONBARCODE-MYLICENSE-KEY-1EF01";
        }

        private async void WriteBarcode(object sender, EventArgs e)
        {
            try
            {
                if (!string.IsNullOrEmpty(barcodeInput.Text))
                {
                    var barcode = BarcodeWriter.CreateBarcode(barcodeInput.Text, BarcodeEncoding.EAN13);

                    // Generate file name
                    string fileExtension = IsGeneratePdfChecked ? "pdf" : "png";
                    string fileName = $"Barcode_{DateTime.Now:yyyyMMddHHmmss}.{fileExtension}";
                    byte[] fileData = IsGeneratePdfChecked ? barcode.ToPdfBinaryData() : barcode.ToPngBinaryData();

                    // Get file saver instance and save the file to the Downloads folder (or Documents on iOS)
                    await SaveToDownloadsAsync(fileData, fileName);

                    await Application.Current.MainPage.DisplayAlert("Saved", "File saved to Downloads folder", "OK");
                }
            }
            catch (Exception ex)
            {
                // Handle exceptions
                System.Diagnostics.Debug.WriteLine(ex);
            }
        }

        private async void WriteQRcode(object sender, EventArgs e)
        {
            try
            {
                if (!string.IsNullOrEmpty(qrInput.Text))
                {
                    var barcode = QRCodeWriter.CreateQrCode(qrInput.Text);

                    // Generate file name
                    string fileExtension = IsGeneratePdfChecked ? "pdf" : "png";
                    string fileName = $"QRcode_{DateTime.Now:yyyyMMddHHmmss}.{fileExtension}";
                    byte[] fileData = IsGeneratePdfChecked ? barcode.ToPdfBinaryData() : barcode.ToPngBinaryData();

                    // Get file saver instance and save the file to the Downloads folder (or Documents on iOS)
                    await SaveToDownloadsAsync(fileData, fileName);

                    await Application.Current.MainPage.DisplayAlert("Saved", "File saved to Downloads folder", "OK");
                }
            }
            catch (Exception ex)
            {
                // Handle exceptions
                System.Diagnostics.Debug.WriteLine(ex);
            }
        }

        private async void ReadBarcode(object sender, EventArgs e)
        {
            try
            {
                var options = new PickOptions
                {
                    PickerTitle = "Please select a file"
                };
                var file = await FilePicker.PickAsync(options);

                OutputText.Text = "";

                if (file != null)
                {
                    using var stream = await file.OpenReadAsync();

                    BarcodeResults result;

                    if (file.ContentType.Contains("image"))
                    {
                        result = BarcodeReader.Read(stream);
                    }
                    else
                    {
                        result = BarcodeReader.ReadPdf(stream);
                    }

                    string barcodeResult = "";
                    int count = 1;

                    result.ForEach(x => { barcodeResult += $"barcode {count}: {x.Value}\n"; count++; });

                    OutputText.Text = barcodeResult;
                }
            }
            catch (Exception ex)
            {
                // Handle exceptions
                System.Diagnostics.Debug.WriteLine(ex);
            }
        }

        public async Task SaveToDownloadsAsync(byte[] fileData, string fileName)
        {
            // if ANDROID
            var downloadsPath = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads);
            var filePath = Path.Combine(downloadsPath.AbsolutePath, fileName);

            try
            {
                // Create the directory if it doesn't exist
                if (!Directory.Exists(downloadsPath.AbsolutePath))
                {
                    Directory.CreateDirectory(downloadsPath.AbsolutePath);
                }

                // Save the file to the Downloads folder
                await File.WriteAllBytesAsync(filePath, fileData);
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine("Error saving file: " + ex.Message);
            }
            // endif
        }
    }
}

Imports Microsoft.VisualBasic
Imports IronBarCode

Namespace IronBarcodeMauiAndroid
	Partial Public Class MainPage
		Inherits ContentPage

		Public Property IsGeneratePdfChecked() As Boolean
			Get
				Return generatePdfCheckBox.IsChecked
			End Get
			Set(ByVal value As Boolean)
				generatePdfCheckBox.IsChecked = value
			End Set
		End Property

		Public Sub New()
			InitializeComponent()
			License.LicenseKey = "IRONBARCODE-MYLICENSE-KEY-1EF01"
		End Sub

		Private Async Sub WriteBarcode(ByVal sender As Object, ByVal e As EventArgs)
			Try
				If Not String.IsNullOrEmpty(barcodeInput.Text) Then
					Dim barcode = BarcodeWriter.CreateBarcode(barcodeInput.Text, BarcodeEncoding.EAN13)

					' Generate file name
					Dim fileExtension As String = If(IsGeneratePdfChecked, "pdf", "png")
					Dim fileName As String = $"Barcode_{DateTime.Now:yyyyMMddHHmmss}.{fileExtension}"
					Dim fileData() As Byte = If(IsGeneratePdfChecked, barcode.ToPdfBinaryData(), barcode.ToPngBinaryData())

					' Get file saver instance and save the file to the Downloads folder (or Documents on iOS)
					Await SaveToDownloadsAsync(fileData, fileName)

					Await Application.Current.MainPage.DisplayAlert("Saved", "File saved to Downloads folder", "OK")
				End If
			Catch ex As Exception
				' Handle exceptions
				System.Diagnostics.Debug.WriteLine(ex)
			End Try
		End Sub

		Private Async Sub WriteQRcode(ByVal sender As Object, ByVal e As EventArgs)
			Try
				If Not String.IsNullOrEmpty(qrInput.Text) Then
					Dim barcode = QRCodeWriter.CreateQrCode(qrInput.Text)

					' Generate file name
					Dim fileExtension As String = If(IsGeneratePdfChecked, "pdf", "png")
					Dim fileName As String = $"QRcode_{DateTime.Now:yyyyMMddHHmmss}.{fileExtension}"
					Dim fileData() As Byte = If(IsGeneratePdfChecked, barcode.ToPdfBinaryData(), barcode.ToPngBinaryData())

					' Get file saver instance and save the file to the Downloads folder (or Documents on iOS)
					Await SaveToDownloadsAsync(fileData, fileName)

					Await Application.Current.MainPage.DisplayAlert("Saved", "File saved to Downloads folder", "OK")
				End If
			Catch ex As Exception
				' Handle exceptions
				System.Diagnostics.Debug.WriteLine(ex)
			End Try
		End Sub

		Private Async Sub ReadBarcode(ByVal sender As Object, ByVal e As EventArgs)
			Try
				Dim options = New PickOptions With {.PickerTitle = "Please select a file"}
				Dim file = Await FilePicker.PickAsync(options)

				OutputText.Text = ""

				If file IsNot Nothing Then
					Dim stream = Await file.OpenReadAsync()

					Dim result As BarcodeResults

					If file.ContentType.Contains("image") Then
						result = BarcodeReader.Read(stream)
					Else
						result = BarcodeReader.ReadPdf(stream)
					End If

					Dim barcodeResult As String = ""
					Dim count As Integer = 1

					result.ForEach(Sub(x)
						barcodeResult &= $"barcode {count}: {x.Value}" & vbLf
						count += 1
					End Sub)

					OutputText.Text = barcodeResult
				End If
			Catch ex As Exception
				' Handle exceptions
				System.Diagnostics.Debug.WriteLine(ex)
			End Try
		End Sub

		Public Async Function SaveToDownloadsAsync(ByVal fileData() As Byte, ByVal fileName As String) As Task
			' if ANDROID
			Dim downloadsPath = Android.OS.Environment.GetExternalStoragePublicDirectory(Android.OS.Environment.DirectoryDownloads)
			Dim filePath = Path.Combine(downloadsPath.AbsolutePath, fileName)

			Try
				' Create the directory if it doesn't exist
				If Not Directory.Exists(downloadsPath.AbsolutePath) Then
					Directory.CreateDirectory(downloadsPath.AbsolutePath)
				End If

				' Save the file to the Downloads folder
				Await File.WriteAllBytesAsync(filePath, fileData)
			Catch ex As Exception
				System.Diagnostics.Debug.WriteLine("Error saving file: " & ex.Message)
			End Try
			' endif
		End Function
	End Class
End Namespace