private void InitBar(SeekBar bar, Android.Media.Stream stream)
 {
     bar.Max      = mgr.GetStreamMaxVolume(stream);
     bar.Progress = mgr.GetStreamVolume(stream);
     bar.SetOnSeekBarChangeListener(new VolumeListener(mgr, stream));
     bar.ProgressChanged += VolumeSeekBar_ProgressChanged;
 }
 public VolumeListener(AudioManager mgr, Android.Media.Stream stream)
 {
     // /!\ is it a correct way to pass information in the constructor ?
     theStream = stream;
     audio     = mgr;
 }