Hi. I am using some apps and they are very good.
˝Ja Sensei˝ helped me to learn Hiragana. Using it you can also learn Katakana, Kanji and there are also many other useful lessons about Japanese culture, grammar and vocabulary.
Then there is ˝Speak Japanese˝ app where you can find the most important phrases from everyday life.
Hope this helps you. On Google play market you can also find many other applications for learning Japanese. :)