Button's style is adding unknown attribute - Android -

i trying achieve of facebook's event page , having trouble copying 3 buttons if person going event.

i trying achieve this,

mine looks this,

this xml buttons

    <linearlayout         android:id="@+id/button_holder"         android:layout_alignparentbottom="true"         android:layout_width="fill_parent"         android:layout_height="wrap_content"         android:orientation="horizontal"         android:weightsum="3"         android:layout_marginleft="10dp"         android:layout_marginstart="10dp"         android:paddingbottom="10dp">          <button             android:id="@+id/button_going"             android:layout_width="0dp"             android:layout_weight="1"             android:layout_height="wrap_content"             android:layout_gravity="center"             android:textsize="14sp"             android:textcolor="@color/secondary_text"             android:text="going"             android:background="@drawable/item_left_button_background"/>          <button             android:id="@+id/button_maybe"             android:layout_width="0dp"             android:layout_weight="1"             android:layout_height="wrap_content"             android:layout_gravity="center"             android:textsize="14sp"             android:textcolor="@color/secondary_text"             android:text="maybe"             android:background="@drawable/item_middle_button_background"/>          <button             android:id="@+id/button_decline"             android:layout_width="0dp"             android:layout_weight="1"             android:layout_height="wrap_content"             android:layout_gravity="center"             android:textsize="14sp"             android:textcolor="@color/secondary_text"             android:text="decline"             android:background="@drawable/item_right_button_background"/>      </linearlayout> 

i not know padding or margin coming above , below buttons. have tried android:padding="0dp" , android:layout_margin="0dp" on buttons had no effect.

my best guess might have layout_weight attribute. may give buttons height based on width, if case how can make buttons shorter?

as applying background item_left_button_background must image or selector consists images images have specific height. when give button height wrap_content take default height of image per suggestion give specific height button or create background images per required sizes