I can't run any app on Android Studio (even a new app that I just have created).
I have tried using GenyMotion emulator and the native android emulator.. when I tried to use the native android emulator it just says "Waiting for device." for hours and nothing happens..
When I tried to use the GenyMotion emulator (which I personally prefer ) it shows me this message:
WARNING: linker: libdvm.so has text relocations. This is wasting memory and is a security risk. Please fix. pkg: /data/local/tmp/com.example.me.FirstApp Failure [INSTALL_FAILED_OLDER_SDK]
for this error I have found this answer, but I don't understand it.
What do I have to do in order to fix it?
According to your story I see that you updated your SDK and then the problem occurred.
I recommend you to redownload the SDK from here and then to replace the existing SDK on your Android Studio.