I have a 6 year old sweet boxer girl, and got my first yorkie ( 3 mo old) just last week. It took them half a day to fall in love with each other !!!
I also have 3 cats, who took longer ( 3 days) but are already taking my Pix into their playtime.
It's adorable to see them all getting along so well !
My only concern is about the boxer being so big and strong and she might unintentionally hurt Pix, but that hasn't happened so far. Bella, the boxer, thinks she is still a puppy and has those crazy times when she runs around the house in high speed , she could knock down an adult human ! Pix is getting aware of her own fragility, and is learning to stay at a distance from those moments and from our feet too.