maui-sample-windows-camera-workaround

This repository contains a sample .NET MAUI camera app that illustrates a workaround to allow capturing photos and videos on Windows.

The problem

Currently, the CapturePhotoAsync and CaptureVideoAsync methods in the default IMediaPicker implementation (MediaPicker.Default) always return null when running on Windows.

The workaround consists of creating a custom IMediaPicker implementation, that uses the launcher to open the Windows Camera app. On the other platform, the default IMediaPicker implementation is used.

Workaround logic

The workaround logic is contained in the platform specific CustomMediaPicker class implementation for Windows:

// Based on code by https://github.com/GiampaoloGabba
// See https://github.com/dotnet/maui/issues/7660

using Windows.Foundation.Collections;
using Windows.Media.Capture;
using Windows.Storage;
using Windows.System;
using WinRT.Interop;

namespace MauiSampleCamera;

public partial class CustomMediaPicker : IMediaPicker
{
	public partial Task<FileResult> CapturePhotoAsync(MediaPickerOptions options = null)
		=> CaptureAsync(false);

	public partial Task<FileResult> CaptureVideoAsync(MediaPickerOptions options = null)
		=> CaptureAsync(true);

	private async Task<FileResult> CaptureAsync(bool isVideo)
	{
		var captureUi = new CustomCameraCaptureUI();

		StorageFile file = await captureUi.CaptureFileAsync(isVideo ? CameraCaptureUIMode.Video : CameraCaptureUIMode.Photo);

		if (file != null)
		{
			return new FileResult(file.Path, file.ContentType);
		}

		return null;
	}

	private class CustomCameraCaptureUI
	{
		private readonly LauncherOptions _launcherOptions;

		public CustomCameraCaptureUI()
		{
			var window = WindowStateManager.Default.GetActiveWindow();
			var handle = WindowNative.GetWindowHandle(window);

			_launcherOptions = new LauncherOptions();
			InitializeWithWindow.Initialize(_launcherOptions, handle);

			_launcherOptions.TreatAsUntrusted = false;
			_launcherOptions.DisplayApplicationPicker = false;
			_launcherOptions.TargetApplicationPackageFamilyName = "Microsoft.WindowsCamera_8wekyb3d8bbwe";
		}

		public async Task<StorageFile> CaptureFileAsync(CameraCaptureUIMode mode)
		{
			var extension = mode == CameraCaptureUIMode.Photo ? ".jpg" : ".mp4";

			var currentAppData = ApplicationData.Current;
			var tempLocation = currentAppData.LocalCacheFolder;
			var tempFileName = $"capture{extension}";
			var tempFile = await tempLocation.CreateFileAsync(tempFileName, CreationCollisionOption.GenerateUniqueName);
			var token = Windows.ApplicationModel.DataTransfer.SharedStorageAccessManager.AddFile(tempFile);

			var set = new ValueSet();
			if (mode == CameraCaptureUIMode.Photo)
			{
				set.Add("MediaType", "photo");
				set.Add("PhotoFileToken", token);
			}
			else
			{
				set.Add("MediaType", "video");
				set.Add("VideoFileToken", token);
			}

			var uri = new Uri("microsoft.windows.camera.picker:");
			var result = await Windows.System.Launcher.LaunchUriForResultsAsync(uri, _launcherOptions, set);
			if (result.Status == LaunchUriStatus.Success && result.Result != null)
			{
				return tempFile;
			}

			return null;
		}
	}
}