Can I learn hacking in my Android mobile?

Yes you can. Android is based on a Linux Kernel so by downloading a terminal emulator from the Google Play Store, you can run Linux commands. The problem is mobile phones have different processor architectures and some important libraries may be missing but this problem may be solved if you are good enough in programming. It recommended to use the app called 'Termux'. You can learn the basics of hacking through this terminal emulator. But if you seriously want to learn some advanced hacking skills, consider getting yourself a PC.