display a progress ring or bar during the process of pdf generation

Question

hello all. i created an app with a collection view and a button. the button allows the user to generate a pdf with the collection view data. the pdf generation worked. but it takes a while like a few seconds because the data is big. this is why i wanted to show a progress bar or ring that appears during the pdf generation process. i used a content view with ActivityIndicator. the thing is that the content view doesn't appear until the pdf is already generated. i alse figured out that the collection view stops scrolling when the pdf is being created. what should i do? this is my code:xaml: xaml.cs: var shareTap = new TapGestureRecognizer(); shareTap.Tapped += (sender, e) => { popupLoadingView.IsVisible = true; activityIndicator.IsRunning = true; requestPermission();};stckshare.GestureRecognizers.Add(shareTap); async public void requestPermission() { var newstatus= Plugin.Permissions.Abstractions.PermissionStatus.Unknown; var status = Plugin.Permissions.Abstractions.PermissionStatus.Unknown; status = await CrossPermissions.Current.CheckPermissionStatusAsync(); if (status != Plugin.Permissions.Abstractions.PermissionStatus.Granted) { newstatus = await CrossPermissions.Current.RequestPermissionAsync(); if (newstatus == Plugin.Permissions.Abstractions.PermissionStatus.Granted) { generatePdf(); } } else { generatePdf(); } } private void generatePdf() { try { PdfDocument document = new PdfDocument(); //Add a new PDF page. PdfPage page = document.Pages.Add(); //Get the font file as stream. Stream fontStream = typeof(MainPage).GetTypeInfo().Assembly.GetManifestResourceStream("isc_alphaApp.Assets.arial.ttf"); //Create a new PdfTrueTypeFont instance. PdfTrueTypeFont font = new PdfTrueTypeFont(fontStream, 14); //Create a new bold stylePdfTrueTypeFont instance. PdfTrueTypeFont boldFont = new PdfTrueTypeFont(fontStream, 14, PdfFontStyle.Bold); page.Graphics.DrawString("Items", boldFont, PdfBrushes.Black, PointF.Empty); //Create PdfGrid. PdfGrid pdfGrid = new PdfGrid(); List list_pdf = new List(); for (int i = 0; i < list_total.Count; i++) { list_pdf.Add(new items_display { Code = list_total[i].itemcode, Description = list_total[i].name, Unit = list_total[i].itemsunitcode, Qty = list_total[i].currentQuantity, Price = list_total[i].CostPrice }); } //Add values to list List data = list_pdf; //Add list to IEnumerable. IEnumerable dataTable = data; PdfStringFormat format_eng = new PdfStringFormat(); format_eng.TextDirection = PdfTextDirection.LeftToRight; format_eng.Alignment = PdfTextAlignment.Center; //Assign data source. pdfGrid.DataSource = dataTable; pdfGrid.Headers[0].Cells[0].StringFormat = format_eng; pdfGrid.Headers[0].Cells[1].StringFormat = format_eng; pdfGrid.Headers[0].Cells[2].StringFormat = format_eng; pdfGrid.Headers[0].Cells[3].StringFormat = format_eng; pdfGrid.Headers[0].Cells[4].StringFormat = format_eng; //Assign bold font to pdfGrid header. pdfGrid.Headers[0].Style.Font = boldFont; //Assign font to PdfGrid. pdfGrid.Style.Font = font; Regex regex = new Regex("[\u0600-\u06ff]|[\u0750-\u077f]|[\ufb50-\ufc3f]|[\ufe70-\ufefc]"); //Create String format with RTL text direction and center text alignment. PdfStringFormat format = new PdfStringFormat(); format.TextDirection = PdfTextDirection.RightToLeft; format.Alignment = PdfTextAlignment.Center; for (int i = 0; i < data.Count; i++) { if (regex.IsMatch(data[i].Code)) { pdfGrid.Rows[i].Cells[0].StringFormat = format; } else { pdfGrid.Rows[i].Cells[0].StringFormat = format_eng; } if (regex.IsMatch(data[i].Description)) { pdfGrid.Rows[i].Cells[1].StringFormat = format; } else { pdfGrid.Rows[i].Cells[1].StringFormat = format_eng; } if (regex.IsMatch(data[i].Unit)) { pdfGrid.Rows[i].Cells[2].StringFormat = format; } else { pdfGrid.Rows[i].Cells[2].StringFormat = format_eng; } pdfGrid.Rows[i].Cells[3].StringFormat = format_eng; pdfGrid.Rows[i].Cells[4].StringFormat = format_eng; } //Assign string format to draw RTL text with center alsignment //pdfGrid.Rows[0].Cells[1].StringFormat = format; //pdfGrid.Rows[1].Cells[1].StringFormat = format; //Draw grid to the page of PDF document. pdfGrid.Draw(page, new Syncfusion.Drawing.PointF(0, 20)); String file_Path; string path = DependencyService.Get().path(); file_Path = System.IO.Path.Combine(path.ToString(), "items.pdf"); FileStream stream = new FileStream(file_Path, FileMode.Create); document.Save(stream); //Close the document document.Close(true); Share.RequestAsync(new ShareFileRequest { Title = "Share PDF", File = new ShareFile(file_Path) }); } catch(Exception exp) { DisplayAlert("No Space", "Not Enough Storage!", "Okay"); } }thanks in advance.

Surya Venkatesan · Answer

Hi rana hodro, 

Thank you for contacting Syncfusion support. 
 
Currently, we are analysing your requirement of displaying a progress ring or bar during the process of PDF generation on our end and we will update the further details on October 28th 2021. 
 
Regards, 
Surya V

Surya Venkatesan · Answer

Hi rana hodro, 
 
Thank you for your patience. 
 
On further analysis, we found PDF generation was happening in the UI thread. We request you to generate the PDF document in separate thread. Once PDF document gets generated, move that PDF to UI thread and need to hide the progress bar. Because, Mobile devices are optimized to run complex tasks on multiple threads. While running with the large PDF file on the UI thread (the main thread) will cause the UI of your application to hang (or at least seem to anyway) until the operation is complete. The fix is to run the task on another thread and return a result back to the UI thread. 
 
Please refer the below link to get more details, 
https://devblogs.microsoft.com/xamarin/getting-started-with-async-await/ 
 
Please let us know if you need any further assistance with this. 
   
Regards,     
Surya V