This app was mentioned in 6 comments, with an average of 1.17 upvotes
When i started to learn Javascript i used great additional source to learn was android mobile app
They have also for Java: Learn Java (maybe they also have for Iphone, idk)
I used the app everywhere i had to wait for something.
There is one for android that I am currently using right now. https://play.google.com/store/apps/details?id=com.sololearn.java&hl=en They also have for html, c++ and python Edit: Oh I didn't see that you wanted something for IOS until later haha!
Here's a list of some useful apps I have on my phone I don't use every one of them though but feel free to try them. Learn Java Learn Python Learn C++ Learn C# Learn PHP tutorialspoint 100+ Java Programs with Output AnkiDroid Flashcards
I hope anyone can find these links useful, and just like others said, make use of the dev docs and othe MOOCs from Udacity,edx,Coursera. All these have free options. Have Fun and Share something you build in the future!!.