title: Android Studio - Facebook Login button render error
body: <p>I have a problem regarding the Facebook SDK and the Login Button. When I tried to put the Login Button, I receive this message</p>
  
  <pre><code>Rendering Problems
  
  The following classes could not be found:
  
  com.facebook.widget.LoginButton (Fix Build Path, Create Class) Tip: Try to build the project
  </code></pre>
  
  <p>I don't know why Android Studio is not rendering the button. I added the module successfully, I can use Facebook SDK classes like Session and so...</p>
  
  <p>Do you know what might be the problem?</p>