XML : Android Image Button not wrapping correctly?

I set Image Button to wrap content an its layout to do the same, but the buttons still showing something like a padding on the top and the bottom.

I already tried setting padding and margin to 0dp, didn't worked.

Image of the layout (Please, ignore the two Image Buttons without image source)

Code:

  <?xml version="1.0" encoding="utf-8"?>  <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"      xmlns:tools="http://schemas.android.com/tools"      android:layout_width="match_parent"      android:layout_height="match_parent"      android:paddingBottom="@dimen/activity_vertical_margin"      android:paddingLeft="@dimen/activity_horizontal_margin"      android:paddingRight="@dimen/activity_horizontal_margin"      android:paddingTop="@dimen/activity_vertical_margin"      tools:context="arensis.grumpyworld.game">        <ImageView          android:layout_width="match_parent"          android:layout_height="match_parent"          android:id="@+id/fondo"          android:scaleType="fitCenter"          android:src="@drawable/fondo1"          android:layout_above="@+id/linearLayout2"          android:layout_centerHorizontal="true" />        <ImageView          android:layout_width="match_parent"          android:layout_height="match_parent"          android:id="@+id/gato"          android:scaleType="fitCenter"          android:src="@drawable/grumpymodel"          android:layout_above="@+id/linearLayout2"          android:layout_centerHorizontal="true" />        <LinearLayout          android:orientation="horizontal"          android:layout_width="match_parent"          android:layout_height="wrap_content"          android:weightSum="3"          android:layout_gravity="center_vertical"          android:layout_alignParentBottom="true"          android:layout_centerHorizontal="true"          android:layout_marginBottom="0dp"          android:id="@+id/linearLayout">            <ImageButton              android:scaleType="fitCenter"              android:id="@+id/mapaico"              android:layout_height="wrap_content"              android:layout_weight="1"              android:layout_width="0dp" />            <ImageButton              android:scaleType="fitCenter"              android:layout_height="wrap_content"              android:layout_weight="1"              android:layout_width="0dp"              android:id="@+id/cazaico"              android:src="@drawable/cazaico" />            <ImageButton              android:scaleType="fitCenter"              android:layout_height="wrap_content"              android:layout_weight="1"              android:layout_width="0dp"              android:id="@+id/dueloico"              />      </LinearLayout>        <LinearLayout          android:orientation="horizontal"          android:layout_width="match_parent"          android:layout_height="wrap_content"          android:weightSum="3"          android:layout_above="@+id/linearLayout"          android:layout_centerHorizontal="true"          android:layout_marginBottom="0dp"          android:id="@+id/linearLayout2">            <ImageButton              android:scaleType="fitCenter"              android:id="@+id/gcico"              android:layout_height="wrap_content"              android:layout_weight="1"              android:layout_width="0dp"              android:src="@drawable/gcico" />            <ImageButton              android:scaleType="fitCenter"              android:layout_height="wrap_content"              android:layout_weight="1"              android:layout_width="0dp"              android:id="@+id/dojoico"              android:src="@drawable/dojoico" />            <ImageButton              android:scaleType="fitCenter"              android:id="@+id/alquimiaico"              android:layout_height="wrap_content"              android:layout_weight="1"              android:layout_width="0dp"              android:src="@drawable/alquimiaico" />        </LinearLayout>    </RelativeLayout>