Fixed null reference errors (#1916)

Added null checks

Author: pictos

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/CameraView/iOS/FormsCameraView.ios.cs

@@ -264,10 +264,13 @@ public void StartRecord()
 				captureSession.AddOutput(videoOutput);
 
 			var audioDevice = AVCaptureDevice.GetDefaultDevice(AVMediaTypes.Audio);
-			var audioInput = AVCaptureDeviceInput.FromDevice(audioDevice);
+			if (audioDevice != null)
+			{
+				var audioInput = AVCaptureDeviceInput.FromDevice(audioDevice);
 
-			if (captureSession.CanAddInput(audioInput))
-				captureSession.AddInput(audioInput);
+				if (audioInput != null && captureSession.CanAddInput(audioInput))
+					captureSession.AddInput(audioInput);
+			}
 
 			captureSession.CommitConfiguration();
 

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/MediaElement/iOS/MediaElementRenderer.ios.cs

@@ -85,7 +85,7 @@ protected virtual void UpdateSource()
 				}
 				else
 				{
-					if (Element.Source is XCT.FileMediaSource fileSource)
+					if (Element.Source is XCT.FileMediaSource fileSource && fileSource.File != null)
 						asset = AVAsset.FromUrl(NSUrl.FromFilename(fileSource.File));
 				}
 

src/CommunityToolkit/Xamarin.CommunityToolkit/Views/Popup/iOS/PopupRenderer.ios.cs

@@ -1,6 +1,7 @@
 using System;
 using System.ComponentModel;
 using CoreGraphics;
+using Intents;
 using UIKit;
 using Xamarin.CommunityToolkit.Helpers;
 using Xamarin.CommunityToolkit.PlatformConfiguration.iOSSpecific;
@@ -180,6 +181,9 @@ void SetSize()
 
 		void SetLayout()
 		{
+			if (PresentationController == null || PopoverPresentationController == null)
+				return;
+
 			((UIPopoverPresentationController)PresentationController).SourceRect = new CGRect(0, 0, PreferredContentSize.Width, PreferredContentSize.Height);
 
 			_ = Element ?? throw new InvalidOperationException($"{nameof(Element)} cannot be null");
@@ -199,6 +203,7 @@ void SetLayout()
 					_ => 0f
 				};
 
+
 				PopoverPresentationController.SourceRect = new CGRect(originX, originY, 0, 0);
 				PopoverPresentationController.PermittedArrowDirections = 0;
 			}
@@ -241,6 +246,10 @@ void SetView()
 
 		void SetPresentationController()
 		{
+
+			if (PresentationController == null)
+				return;
+
 			var popOverDelegate = new PopoverDelegate();
 			popOverDelegate.PopoverDismissed += HandlePopoverDelegateDismissed;
 
@@ -284,8 +293,7 @@ protected override void Dispose(bool disposing)
 					Element.PropertyChanged -= OnElementPropertyChanged;
 					Element = null;
 
-					var presentationController = (UIPopoverPresentationController)PresentationController;
-					if (presentationController != null)
+					if (PresentationController is UIPopoverPresentationController presentationController)
 						presentationController.Delegate = null;
 				}
 			}