I just don't get it. I am following a tutorial and in the project that he opened the component tree is not empty, it has a constraint layout and a button and he also can add buttons, but in my fresh project there isn't any layout or button please help.(The layout that I chose is "Basic Activity".) photo
PS:I can't add anything.
I had the same issue. Re-installing or resetting Android Studio alone didn't help. I finally solved it by also re-installing the whole Android SDK. The directories for resetting the IDE are:
%USERPROFILE%\AppData\Roaming\Google\AndroidStudioPreview4.2
%USERPROFILE%\AppData\Local\Google\AndroidStudioPreview4.2
(or whatever version of Android Studio you're currently on)