preguntar acerca de surfaceholder

J'obtiens ces erreurs de LogCat: 10-30 00:31:51.494: D/CameraHal(1205): CameraHal setOverlay/1/00000000/00000000 10-30 00:31:51.494: E/CameraHal(1205): Trying to set overlay, but overlay is null!, line:3472 10-30 00:31:51.494: W/CameraService( …