Hello there,
Can you help me how to fix this problem?
Im already import all libs related to androidx.core, but none of the libs can solve it.
Androidx.core Error
Afaik aide does not support Android X yet. (Not officially) as there are some tricks to make AIDE support it, but it is not recommend because it can lead to more problems .
Ok thanks, but im still curious, can you tell me the trick? 
No Problem if i got more problems.
Gotta change .jar core
Ok, the trick is to use AIDE mate, create an empty project, and make sure “use androidx artifacts” is enabled. Then openness t with aide, 3 errors will appear, click on each one and rename the tag that is repeated
Example : fontIcon to “fontIcon2”
Save the fixed libraries and there you go