Maybe. But probably not. While hiking, playing with your pet, exercising, painting and so on CAN be an exercise in mindfulness, in reality it very rarely is. While many activities can be relaxing or diverting, to successfully bring the skills of mindfulness (concentration power, sensory clarity, and equanimity) to such activities usually requires a great deal of prior training meditating in stillness.
Indeed most experienced meditators consider meditation in motion to be an advanced practice. So by all means continue to exercise, practice martial arts, play with your pets, and so on, but it is very likely not giving you the same benefits as a mindfulness meditation practice in stillness. Consider the answer to the next FAQ and decide for yourself.