it is because all the android developers prefer to use java . most of the mobile software is developed using an android studio or kotlin which uses java. it is more portable and has more functionalities than kivy which is based on python. note that kivy doesn’t support python 3.8.
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It is worth learning . It can help you to create apps more quickly, if your making mobile apps all you need is one code to target all platforms (android and iOS) and if your into android development it is easier than the android studio (I don’t know about iOS and xcode).
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