need to change default ringtone with xamarin

Question

need to change default ringtone with xamarin i use android.net.parse with path string and return null, then i use the bellow code where i find online and again return null anybody can help?

var ring1 = ("file:////storage/emulated/0/Ringtones/" + item.ringtone);
     ContentValues values = new ContentValues();

                            values.Put(MediaStore.IMediaColumns.Data, ring1);
                            values.Put(MediaStore.Audio.Media.InterfaceConsts.IsRingtone, true);
                            values.Put(MediaStore.IMediaColumns.MimeType, "audio/mp3");



                            var uri = MediaStore.Audio.Media.GetContentUriForPath(path: ring1);


                            Android.Net.Uri newUri = this.ContentResolver.Insert(uri, values);

    RingtoneManager.SetActualDefaultRingtoneUri(Android.App.Application.Context,RingtoneType.Ringtone, newUri);

"uri" and "values" in debugging have values but parameter newUri is null

Answer 1

The problem was in write permisions i use the code below to check if the file exist ask for permision and change the ringtone and work

var newuri3 = Android.Net.Uri.Parse("file:///storage/emulated/0/Ringtones/" + item.ringtone);

                    var newuri = newuri3;
                    bool b = false;
                    if (null != newuri)
                    {
                        try
                        {
                            var inputStream = Android.App.Application.Context.ContentResolver.OpenInputStream(newuri);
                            inputStream.Close();
                            Console.WriteLine("file exist");
                            b = true;
                        }
                        catch (Exception e)
                        {
                            Console.WriteLine("File corresponding to the uri does not exist " + newuri.ToString());
                        }
                    }

                    var bi = Settings.System.CanWrite(Android.App.Application.Context);
                    if (bi)
                    {
                        Console.WriteLine("it haw write permision");
                    }
                    else
                    {
                        Console.WriteLine("doenst have permision");



                        Intent intent = new Intent(Settings.ActionManageWriteSettings);
                        intent.SetData(Android.Net.Uri.Parse($"package:{Android.App.Application.Context.PackageName}"));
                        intent.AddFlags(ActivityFlags.NewTask);
                        Android.App.Application.Context.StartActivity(intent);

                    }



                    RingtoneManager.SetActualDefaultRingtoneUri(Android.App.Application.Context, RingtoneType.Ringtone, newuri);

where item.ringtone is the file name for example music.mp3