Disable Camera option on ProcessAndRenderPage on Android when there are 0 cameras.

Emgu.CV.Runtime/Maui/UI/ButtonTextImagePage.cs

@@ -247,11 +247,10 @@ namespace Emgu.CV.Platform.Maui.UI
         {
             Mat[] mats = new Mat[imageNames.Length];
 
-            for (int i = 0; i < mats.Length; i++)
-            {
-                String pickImgString = "Use Image from";
-                if (labels != null && labels.Length > i)
-                    pickImgString = labels[i];
+            SetMessage("Checking if camera option is available, please wait...");
+            //Run it once in case it need to check if camera is available, which could take a long time to run
+            await Task.Run(() => { bool cameraOption = this.HasCameraOption; });
+            SetMessage(null);
 
             bool captureSupported;
 
@@ -264,8 +263,22 @@ namespace Emgu.CV.Platform.Maui.UI
             else
             {
                 captureSupported = MediaPicker.IsCaptureSupported;
+                if (Microsoft.Maui.Devices.DeviceInfo.Platform == DevicePlatform.Android)
+                {
+                    //Overwrite MediaPicker if there is no camera on this Android device.
+                    if (!this.HasCameraOption)
+                    {
+                        captureSupported = false;
+                    }
+                }
             }
 
+            for (int i = 0; i < mats.Length; i++)
+            {
+                String pickImgString = "Use Image from";
+                if (labels != null && labels.Length > i)
+                    pickImgString = labels[i];
+
                 String action;
                 List<String> options = new List<string>();
                 options.Add("Default");
@@ -275,11 +288,6 @@ namespace Emgu.CV.Platform.Maui.UI
                 if (captureSupported)
                     options.Add("Photo from Camera");
 
-                SetMessage("Checking if camera option is available, please wait...");
-                //Run it once in case it need to check if camera is available, which could take a long time to run
-                await Task.Run(() => { bool cameraOption = this.HasCameraOption; });
-                SetMessage(null);
-
                 if (this.HasCameraOption)
                 {
                     if (Microsoft.Maui.Devices.DeviceInfo.Platform == DevicePlatform.Android)

Emgu.CV.Runtime/Maui/UI/ProcessAndRenderPage.cs

@@ -89,7 +89,12 @@ namespace Emgu.CV.Platform.Maui.UI
             {
 #if __ANDROID__
                 if (CameraBackend == AndroidCameraBackend.AndroidCamera2)
-                    return true;
+                {
+                    var context = Android.App.Application.Context;
+                    var cameraManager =  (Android.Hardware.Camera2.CameraManager) context.GetSystemService(Android.Content.Context.CameraService);
+                    var cameraCount = cameraManager?.GetCameraIdList()?.Length;
+                    return cameraCount > 0;
+                }
 #endif
 
                 if (CvInvoke.Backends.Length > 0)