Japanese on mobile phone

Hi (Sorry for the strange user name)

I want to study Japanese, And I’m looking for tools to learn the Japanese writing on my mobile phone. It’s the perfect way to practice during school breaks or when I need to sit long in the bus/train

I hope someone know some program(s) to learn how to read and write Kana (Kanji is optional)

(I have a Samsung pixon,(Touchscreen) in case it is important (I realized to late the Iphone could offer me more programs)