I already tried several answers I could find but none of them worked with the latest Facebook Android SDK version 4.0.
How can I change the layout height with the latest SDK?
Just set paddingTop and paddingBottom. It works for me.
<com.facebook.login.widget.LoginButton
android:id="@+id/login_facebook_button"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="15dp"
android:paddingBottom="15dp"
android:layout_marginRight="30dp"
android:layout_marginLeft="30dp"/>