Android - The following classes could not be instantiated

Question

I'm a total beginner I just started learning android development and i'm trying to print "Hello World" with the "material light theme" but I have this problem

the following classes could not be instantiated 
 - android.support.design.widget.coordinatorLayout
 - android.support.design.widget.AppBarLayout
 - android.support.design.widget.FloatingActionButton

Answer 1

Did you add theese lines in your build.gradle :

compile 'com.android.support:appcompat-v7:23.4.0'
compile 'com.android.support:support-v4:23.4.0'
compile 'com.android.support:design:23.4.0'

And then sync , rebuild your project. Also update Android Sdk Tools in Sdk Manager to latest version.

@Edit , for @Maza :

First of all open build.gradle like, If you can't see this page in left side of Android Studio try to press Ctrl + 1 keys:

Then you should see a window like that :

Thats it. Now you can add any dependencies in your build.gradle !