If you were using the default auto settings to take that photo you should try disabling some of them to see if you get a shot more to your liking, but that starburst lens flare effect will be hard to eliminate completely in a night shot like that, the lenses in our smartphones are great for most shots but once you're trying something more challenging than we just have to accept or work around their limitations.
-- Try changing the 'Metering' from Center-weighted to Matrix so the camera's light meter is targeting the whole frame and not just the center.
-- You might also want to enable the camera's flash, although if you want that darkened room contrast to highlight your wonderful tree that might be too lit up overall. You could take small piece of paper and hold it directly against the flash LED -- that will allow some light to come through but as much.
-- Also try playing with the ISO, higher is more light sensitive but this will have a big effect on overall contrast, but this is harder manipulate so it could make the shot all blown out or just dark and muddy. With a typical DSLR camera there's an adjustable aperture but with out smartphone cameras we just need to compensate in other ways.
