Handling Images from the Camera and Photo Gallery in Xamarin Android

MainActivity.cs

protected override void OnActivityResult(int requestCode, Result resultCode, Intent data)
{
	base.OnActivityResult(requestCode, resultCode, data);

	//Camera Request
	if (requestCode == 0)
	{
		if (resultCode == Result.Ok)
		{
                    Task.Run(() =>
                    {
                        if (App.selectedImageId != null)
			{
				var documentsDirectry = Forms.Context.GetExternalFilesDir(Android.OS.Environment.DirectoryPictures);
                            	string pngFilename = System.IO.Path.Combine(documentsDirectry.AbsolutePath, App.selectedPetForPhoto.PetId + "." + CoreBag.Models.FileFormatEnum.JPEG.ToString());

				if (File.Exists(pngFilename))
				{
					Java.IO.File file = new Java.IO.File(documentsDirectry, App.selectedImageId + "." + FileFormatEnum.JPEG.ToString());
					Android.Net.Uri uri = Android.Net.Uri.FromFile(file);

					//Read the meta data of the image to determine what orientation the image should be in
					var originalMetadata = new ExifInterface(pngFilename);
					int orientation = GetRotation(originalMetadata);

                                	var fileName = App.selectedPetForPhoto.PetId + "." + FileFormatEnum.JPEG.ToString();
                                	HandleBitmap(uri, orientation, fileName);
				}
			}
                    });
		}
	}
	else if(requestCode == 1)
        {
        	if(resultCode == Result.Ok)
                {
			if (data.Data != null)
			{
				//Grab the Uri which is holding the path to the image
				Android.Net.Uri uri = data.Data;

				string fileName = null;

                       	 	if (App.selectedPetForPhoto != null)
                        	{
                            		fileName = App.selectedImageId + "." + FileFormatEnum.JPEG.ToString();
                           	 	var pathToImage = GetPathToImage(uri);
                            		var originalMetadata = new ExifInterface(pathToImage);
                            		int orientation = GetRotation(originalMetadata);

					HandleBitmap(uri, orientation, fileName);
                        	}
			}
                }
            }
	}
    
    /*
     *  https://stackoverflow.com/questions/26597811/xamarin-choose-image-from-gallery-path-is-null
     */
     private string GetPathToImage(Android.Net.Uri uri)
     {
            string doc_id = "";
            using (var c1 = ContentResolver.Query(uri, null, null, null, null))
            {
                c1.MoveToFirst();
                String document_id = c1.GetString(0);
                doc_id = document_id.Substring(document_id.LastIndexOf(":") + 1);
            }

            string path = null;

            // The projection contains the columns we want to return in our query.
            string selection = Android.Provider.MediaStore.Images.Media.InterfaceConsts.Id + " =? ";
            using (var cursor = ManagedQuery(Android.Provider.MediaStore.Images.Media.ExternalContentUri, null, selection, new string[] { doc_id }, null))
            {
                if (cursor == null) return path;
                var columnIndex = cursor.GetColumnIndexOrThrow(Android.Provider.MediaStore.Images.Media.InterfaceConsts.Data);
                cursor.MoveToFirst();
                path = cursor.GetString(columnIndex);
            }
            return path;
        }

public int GetRotation(ExifInterface exif)
{
	try
	{
		var orientation = (Android.Media.Orientation)exif.GetAttributeInt(ExifInterface.TagOrientation, (int)Android.Media.Orientation.Normal);

		switch (orientation)
		{
			case Android.Media.Orientation.Rotate90:
				return 90;
			case Android.Media.Orientation.Rotate180:
				return 180;
			case Android.Media.Orientation.Rotate270:
				return 270;
			default:
				return 0;
		}
	}
	catch (Exception ex)
	{
        	App.WriteOutput(ex.ToString());
                return 0;
	}
}
    
public async Task HandleBitmap(Android.Net.Uri uri, int orientation, string imageId)
{
	try
        {
        	Bitmap mBitmap = Android.Provider.MediaStore.Images.Media.GetBitmap(this.ContentResolver, uri);
                Bitmap myBitmap = null;

                if (mBitmap != null)
                {
                    //In order to rotate the image we create a Matrix object, rotate if the image is not already in it's correct orientation
                    Matrix matrix = new Matrix();
                    if (orientation != 0)
                    {
                        matrix.PreRotate(orientation);
                    }
   
                    myBitmap = Bitmap.CreateBitmap(mBitmap, 0, 0, mBitmap.Width, mBitmap.Height, matrix, true);

                    MemoryStream stream = new MemoryStream();

                    //Compressing by 50%, feel free to change if file size is not a factor
                    myBitmap.Compress(Bitmap.CompressFormat.Jpeg, 50, stream);

                    byte[] bitmapData = stream.ToArray();

                    //Save the image if a file name was supplied. 
                    if (imageId != null && imageId != "")
                    {
                        SavePictureToDisk(myBitmap, imageId);
                    }
			
	 	    //Send image byte array back to UI
                    MessagingCenter.Send<byte[]>(bitmapData, "ImageSelected");
                }   
            }
            catch(Exception e)
            {
                App.WriteOutput(e.ToString());
            }
}
    
public void SavePictureToDisk(Bitmap source, string imageName)
{
	try
        {
        	Task.Run(() =>
                {
                    var documentsDirectry = Forms.Context.GetExternalFilesDir(Android.OS.Environment.DirectoryPictures);
                    string pngFilename = System.IO.Path.Combine(documentsDirectry.AbsolutePath, imageName);

                    //If the image already exists, delete, and make way for the updated one
                    if (File.Exists(pngFilename))
                    {
                        File.Delete(pngFilename);
                    }

                    using (FileStream fs = new FileStream(pngFilename, FileMode.OpenOrCreate))
                    {
                        source.Compress(Bitmap.CompressFormat.Jpeg, 50, fs);
                        fs.Close();
                    }

                    App.WriteOutput("Saved photo");
                });
            }
            catch(Exception e)
            {
                App.WriteOutput(e.ToString());
            }
}

does it work with xamarin or dropbox?