Xamarin.Forms save file (pdf) in local storage and open with the default viewer

Question

Edited to fine the question

In Android, I need to download a pdf file to \"Documents\" folder and open it with the default program. I downloaded the

Answer 1

I found a way to save and open the file:

    /// 

    /// Save data bytes on "My documents" folder and open
    /// 
    /// Filename, for example: "Test.pdf"
    /// Array of bytes to save
    /// True if success or false if error
    public bool SaveAndOpen(string fileName, byte[] data)
    {
        try
        {
            // Get my downloads path
            string filePath = Path.Combine(Android.OS.Environment.ExternalStorageDirectory.AbsolutePath, Android.OS.Environment.DirectoryDownloads);

            // Combine with filename
            string fullName = Path.Combine(filePath, fileName);

            // If the file exist on device delete it
            if (File.Exists(fullName))
            {
                // Note: In the second run of this method, the file exists
                File.Delete(fullName);
            }

            // Write bytes on "My documents"
            File.WriteAllBytes(fullName, data);

            // Get the uri for the saved file
            Android.Net.Uri file = Android.Support.V4.Content.FileProvider.GetUriForFile(
                this,
                this.PackageName + ".fileprovider",
                new Java.IO.File(fileName));
            Intent intent = new Intent(Intent.ActionView);
            intent.SetDataAndType(file, "application/pdf");
            intent.SetFlags(ActivityFlags.ClearWhenTaskReset | ActivityFlags.NewTask | ActivityFlags.GrantReadUriPermission | ActivityFlags.NewTask);
            this.ApplicationContext.StartActivity(intent);

            return true;
        }
        catch (Exception ex)
        {
            Console.WriteLine("ERROR: " + ex.Message + ex.StackTrace);
            return false;
        }
    }

It's needed to request the permissions at runtime. I used Plugin.Permisions available on Nuget:

    Plugin.Permissions.PermissionsImplementation.Current.RequestPermissionsAsync(
         new Plugin.Permissions.Abstractions.Permission[]
         {
             Plugin.Permissions.Abstractions.Permission.Storage,
             Plugin.Permissions.Abstractions.Permission.MediaLibrary
         });

Also add a provider in the AndroidManifest.xml file:

In the same AndroidManifest add permisions for:

And add an external path in Resources/xml/file_paths.xml

Don't know if I have not needed permissions, but with this way works.