Fix camera package fails to build with latest Maui version (#2916)

* Improve null safety and update dependencies

Enhanced null safety across CameraManager.android.cs by adding null-conditional operators (`?`) to prevent potential null reference exceptions. Updated `CameraViewPage.xaml` to bind `Picker` to `SelectedCamera.Name` for accurate UI display.

Upgraded `Xamarin.AndroidX.Camera` dependencies to version 1.5.0 and added `Xamarin.AndroidX.Activity.Ktx` for improved functionality and compatibility. Adjusted `CameraProvider.android.cs` to handle null values and ensure robust camera initialization.

* Improve camera binding, resolution, and recording quality

Updated CameraViewPage.xaml to fix data binding issues by modifying the `ItemDisplayBinding` property of the `Picker`.

Enhanced CameraManager.android.cs with the following changes:
- Improved resolution selection logic in `UpdateCaptureResolution` by prioritizing higher resolution over capture rate.
- Enhanced image capture quality in `StartUseCase` by setting capture mode to maximize quality and applying the resolution selector.
- Added audio support and proper initialization for video recording in `PlatformStartVideoRecording`.

These changes improve the overall functionality and quality of the camera features.

* Update src/CommunityToolkit.Maui.Camera/CameraManager.android.cs

Co-authored-by: Copilot <[email protected]>

* Ignore the camera if `Camera2CameraInfo.From` returns `null`

* Update Builder Patterns

* Update CameraProvider.android.cs

---------

Co-authored-by: Copilot <[email protected]>
Co-authored-by: Brandon Minnick <[email protected]>

Author: 3 people

samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/CameraViewPage.xaml

@@ -64,7 +64,7 @@
                 <Picker 
                     Title="Cameras" 
                     ItemsSource="{Binding Cameras}"
-                    ItemDisplayBinding="{Binding Name}" 
+                    ItemDisplayBinding="{Binding Name, x:DataType={x:Null}}" 
                     SelectedItem="{Binding SelectedCamera}" />
 
                 <Picker 

src/CommunityToolkit.Maui.Camera/CameraManager.android.cs

@@ -124,9 +124,13 @@ public async partial ValueTask UpdateCaptureResolution(Size resolution, Cancella
 		resolutionSelector?.Dispose();
 
 		resolutionSelector = new ResolutionSelector.Builder()
-			.SetAllowedResolutionMode(ResolutionSelector.PreferHigherResolutionOverCaptureRate)
+			.SetAllowedResolutionMode(ResolutionSelector.PreferHigherResolutionOverCaptureRate)?
 			.SetResolutionFilter(resolutionFilter)
-			.Build();
+			?.Build() ?? throw new InvalidOperationException("Unable to Set Resolution Filter");
+		
+		// `.SetResolutionFilter()` should never return null
+		// According to the Android docs, `ResolutionSelector.Builder.setResolutionFilter(ResolutionFilter)` returns a `NonNull` object
+		// `ResolutionSelector.Builder.SetResolutionFilter(ResolutionFilter)` returning a nullable object in .NET for Android is likely a C# Binding mistake
 
 		if (IsInitialized)
 		{
@@ -229,23 +233,33 @@ protected async Task StartUseCase(CancellationToken token)
 		videoCapture?.Dispose();
 		videoRecorder?.Dispose();
 
-		cameraPreview = new Preview.Builder().SetResolutionSelector(resolutionSelector).Build();
-		cameraPreview.SetSurfaceProvider(cameraExecutor, previewView?.SurfaceProvider);
+		cameraPreview = new Preview.Builder().SetResolutionSelector(resolutionSelector)?.Build();
+		cameraPreview?.SetSurfaceProvider(cameraExecutor, previewView?.SurfaceProvider);
 
 		imageCapture = new ImageCapture.Builder()
-			.SetCaptureMode(ImageCapture.CaptureModeMaximizeQuality)
+			.SetCaptureMode(ImageCapture.CaptureModeMaximizeQuality)?
 			.SetResolutionSelector(resolutionSelector)
-			.Build();
+			?.Build() ?? throw new InvalidOperationException("Unable to set resolution selector");
+		
+		// `.SetResolutionFilter()` should never return null
+		// According to the Android docs, `ResolutionSelector.Builder.SetResolutionFilter(ResolutionFilter)` returns a `NonNull` object
+		// `ResolutionSelector.Builder.SetResolutionFilter(ResolutionFilter)` returning a nullable object in .NET for Android is likely a C# Binding mistake
+		// https://developer.android.com/reference/androidx/camera/core/resolutionselector/ResolutionSelector.Builder#setResolutionFilter(androidx.camera.core.resolutionselector.ResolutionFilter)
 
 		var videoRecorderBuilder = new Recorder.Builder()
-			.SetExecutor(cameraExecutor);
+			.SetExecutor(cameraExecutor) ?? throw new InvalidOperationException("Unable to set video recorder executor");
+		
+		// `.SetExecutor()` should never return null
+		// According to the Android docs, `ResolutionSelector.Builder.setExecutor(ResolutionFilter)` returns a `NonNull` object
+		// `ResolutionSelector.Builder.SetExecutor(ResolutionFilter)` returning a nullable object in .NET for Android is likely a C# Binding mistake
+		// https://developer.android.com/reference/androidx/camera/video/Recorder.Builder#setExecutor(java.util.concurrent.Executor)
 
 		if (Quality.Highest is not null)
 		{
-			videoRecorderBuilder = videoRecorderBuilder.SetQualitySelector(QualitySelector.From(Quality.Highest));
+			videoRecorderBuilder = videoRecorderBuilder?.SetQualitySelector(QualitySelector.From(Quality.Highest));
 		}
 
-		videoRecorder = videoRecorderBuilder.Build();
+		videoRecorder = videoRecorderBuilder?.Build();
 		videoCapture = VideoCapture.WithOutput(videoRecorder);
 
 		await StartCameraPreview(token);
@@ -271,9 +285,9 @@ protected virtual async partial Task PlatformStartCameraPreview(CancellationToke
 		camera = await RebindCamera(processCameraProvider, cameraView.SelectedCamera, token, cameraPreview, imageCapture, videoCapture);
 		cameraControl = camera.CameraControl;
 
-		var point = previewView.MeteringPointFactory.CreatePoint(previewView.Width / 2.0f, previewView.Height / 2.0f, 0.1f);
+		var point = previewView.MeteringPointFactory?.CreatePoint(previewView.Width / 2.0f, previewView.Height / 2.0f, 0.1f);
 		var action = new FocusMeteringAction.Builder(point).Build();
-		camera.CameraControl.StartFocusAndMetering(action);
+		camera.CameraControl?.StartFocusAndMetering(action);
 
 		IsInitialized = true;
 		OnLoaded.Invoke();
@@ -344,8 +358,13 @@ protected virtual async partial Task PlatformStartVideoRecording(Stream stream,
 		var executor = ContextCompat.GetMainExecutor(context) ?? throw new CameraException($"Unable to retrieve {nameof(IExecutorService)}");
 		videoRecording = videoRecorder
 			.PrepareRecording(context, outputOptions)
-			.WithAudioEnabled()
-			.Start(executor, captureListener);
+			?.WithAudioEnabled()
+			.Start(executor, captureListener) ?? throw new InvalidOperationException("Unable to prepare recording");
+		
+		// `.PrepareRecording()` should never return null
+		// According to the Android docs, `Recorder.prepareRecording(Context, eMediaSoreOutputOptions)` returns a `NonNull` object
+		// `Recorder.PrepareRecording(Context, eMediaSoreOutputOptions)` returning a nullable object in .NET for Android is likely a C# Binding mistake
+		// https://developer.android.com/reference/androidx/camera/video/Recorder#prepareRecording(android.content.Context,androidx.camera.video.MediaStoreOutputOptions)
 	}
 
 	protected virtual async partial Task<Stream> PlatformStopVideoRecording(CancellationToken token)
@@ -415,7 +434,9 @@ async Task<CameraSelector> EnableModes(CameraInfo selectedCamera, CancellationTo
 				return;
 			}
 
-			var extensionsManagerFuture = ExtensionsManager.GetInstanceAsync(context, cameraProviderInstance);
+			var extensionsManagerFuture = ExtensionsManager.GetInstanceAsync(context, cameraProviderInstance) 
+			                              ?? throw new InvalidOperationException("Unable to get listenable future for camera provider");;
+			
 			extensionsManagerFuture.AddListener(new Runnable(() =>
 			{
 				var extensionsManager = (ExtensionsManager?)extensionsManagerFuture.Get();
@@ -455,10 +476,10 @@ void SetImageCaptureTargetRotation(int rotation)
 
 	sealed class ImageCallBack(ICameraView cameraView) : ImageCapture.OnImageCapturedCallback
 	{
-		public override void OnCaptureSuccess(IImageProxy image)
+		public override void OnCaptureSuccess(IImageProxy? image)
 		{
 			base.OnCaptureSuccess(image);
-			var img = image.Image;
+			var img = image?.Image;
 
 			if (img is null)
 			{
@@ -471,7 +492,7 @@ public override void OnCaptureSuccess(IImageProxy image)
 			if (buffer is null)
 			{
 				cameraView.OnMediaCapturedFailed("Unable to obtain a buffer for the image plane.");
-				image.Close();
+				image?.Close();
 				return;
 			}
 
@@ -489,7 +510,7 @@ public override void OnCaptureSuccess(IImageProxy image)
 			}
 			finally
 			{
-				image.Close();
+				image?.Close();
 			}
 
 			static Image.Plane? GetFirstPlane(Image.Plane[]? planes)
@@ -503,24 +524,26 @@ public override void OnCaptureSuccess(IImageProxy image)
 			}
 		}
 
-		public override void OnError(ImageCaptureException exception)
+		public override void OnError(ImageCaptureException? exception)
 		{
 			base.OnError(exception);
-			cameraView.OnMediaCapturedFailed(exception.Message ?? "An unknown error occurred.");
+			cameraView.OnMediaCapturedFailed(exception?.Message ?? "An unknown error occurred.");
 		}
 	}
 
 	sealed class ResolutionFilter(Android.Util.Size size) : Object, IResolutionFilter
 	{
 		public Android.Util.Size TargetSize { get; set; } = size;
 
-		public IList<Android.Util.Size> Filter(IList<Android.Util.Size> supportedSizes, int rotationDegrees)
+		public IList<Android.Util.Size> Filter(IList<Android.Util.Size>? supportedSizes, int rotationDegrees)
 		{
-			var filteredList = supportedSizes
+			var filteredList = supportedSizes?
 				.Where(size => size.Width <= TargetSize.Width && size.Height <= TargetSize.Height)
 				.OrderByDescending(size => size.Width * size.Height).ToList();
 
-			return filteredList.Count is 0 ? supportedSizes : filteredList;
+			return filteredList is null || filteredList.Count is 0 
+				? supportedSizes ?? [] 
+				: filteredList;
 		}
 	}
 

src/CommunityToolkit.Maui.Camera/CommunityToolkit.Maui.Camera.csproj

@@ -52,10 +52,12 @@
 
   <ItemGroup Condition="$([MSBuild]::GetTargetPlatformIdentifier('$(TargetFramework)')) == 'android'">
     <!-- Required NuGet Packages -->
-    <PackageReference Include="Xamarin.AndroidX.Camera.Camera2" Version="1.4.2.2" />
-    <PackageReference Include="Xamarin.AndroidX.Camera.View" Version="1.4.2.2" />
-    <PackageReference Include="Xamarin.AndroidX.Camera.Extensions" Version="1.4.2.2" />
+    <PackageReference Include="Xamarin.AndroidX.Camera.Camera2" Version="1.5.0" />
+    <PackageReference Include="Xamarin.AndroidX.Camera.View" Version="1.5.0" />
+    <PackageReference Include="Xamarin.AndroidX.Camera.Extensions" Version="1.5.0" />
 
+    <PackageReference Include="Xamarin.AndroidX.Activity.Ktx" Version="1.11.0" />
+    
     <!--  Ensure Linker does not remove required libraries -->
     <None Include="linker.xml" Pack="true" PackagePath="build\$(PackageId).LinkerConfigurationFile.xml" />
   </ItemGroup>

src/CommunityToolkit.Maui.Camera/Providers/CameraProvider.android.cs

@@ -30,6 +30,14 @@ public async partial ValueTask RefreshAvailableCameras(CancellationToken token)
 			foreach (var cameraXInfo in processCameraProvider.AvailableCameraInfos)
 			{
 				var camera2Info = Camera2CameraInfo.From(cameraXInfo);
+				if (camera2Info is null)
+				{
+					// `Camera2CameraInfo.From` should never return `null`
+					// According to the Android Docs, `Camera2CameraInfo.From` returns a `NonNull`
+					// `Camera2CameraInfo.From` returning a nullable `Camera2CameraInfo` object is likely a C# binding mistake
+					// https://developer.android.com/reference/androidx/camera/camera2/interop/Camera2CameraInfo
+					continue;
+				}
 
 				var (name, position) = cameraXInfo.LensFacing switch
 				{
@@ -68,13 +76,13 @@ public async partial ValueTask RefreshAvailableCameras(CancellationToken token)
 				}
 
 				var cameraInfo = new CameraInfo(name,
-					camera2Info.CameraId,
+					camera2Info.CameraId ?? throw new InvalidOperationException("Unable to retrieve Camera ID"),
 					position,
 					cameraXInfo.HasFlashUnit,
-					(cameraXInfo.ZoomState.Value as IZoomState)?.MinZoomRatio ?? 1.0f,
-					(cameraXInfo.ZoomState.Value as IZoomState)?.MaxZoomRatio ?? 1.0f,
+					(cameraXInfo.ZoomState?.Value as IZoomState)?.MinZoomRatio ?? 1.0f,
+					(cameraXInfo.ZoomState?.Value as IZoomState)?.MaxZoomRatio ?? 1.0f,
 					supportedResolutions,
-					cameraXInfo.CameraSelector);
+					cameraXInfo.CameraSelector ?? throw new InvalidOperationException($"Unable to retrieve {nameof(ICameraInfo.CameraSelector)}"));
 
 				availableCameras.Add(cameraInfo);
 			}