I\'m toying with Android Studio making a very simple very stupid app to learn about saving key preferences and I ran into a weird obstacle. I\'ll try to provide as much as I can
It appears that you have two onCreate methods. Try removing the second one and running it again.
In Android Studio you need create a Run Configuration in your project.
Go to this link to left run icon
And click on Edit Configuration, after in the windows configure like this:
And save it, for test click run icon.