cannot reslove symbol XXX
Implementation has been carried out in the build.gradle file, but the import in java still reports red.
Solution (clear the cache and restart): File --> Invalidate Caches / Restart
Package android.support.* does not exist error
The solution is very simple, modify gradle.properties, change
1. android.useAndroidX = true to false
2. android.enableJetifier = true to false
3. Resynchronize and it will be OK